Shoulder & Elbow

ABSTRACT

Injuries to the distal biceps occur at the tendinous insertion at the radial tuberosity. Distal biceps injuries range from tendinosis to partial tears to non-retracted and retracted complete tears. Acute and chronic complete tears result from a tendinous avulsion at the radial tuberosity. Acute tears result from a strong force exerted on an eccentric biceps contraction, leading to tendon injury.

Distal biceps tendon injuries are uncommon (1.2 per 100,000 patients in one study).¹ An underlying degenerative component is involved in all distal biceps tendon tears and tendinosis.² Partial tears can be caused by the same mechanism or by no particular inciting event.³ Magnetic resonance imaging (MRI) is the optimal imaging modality for distal tendon tears because of its excellent specificity and sensitivity in the detection of complete tears.^4,5 Imaging also accurately diagnoses and characterizes partial tears and tendinosis.⁵ On MRI, fast spin-echo intermediate-weighted and T2-weighted or short tau inversion recovery (STIR) sequences are normally obtained to assess tendon integrity. Along with standard axial and sagittal views, the FABS (flexed elbow, abducted shoulder, supinated forearm) view is an important tool in the diagnosis of distal biceps tendon tears.⁶ The FABS view is obtained with the patient prone with the shoulder abducted 180° (above the head), with the elbow flexed to 90°, and the forearm supinated. This position allows a longitudinal view of along the entire length of the distal tendon.

Complete distal biceps tears can usually be diagnosed by history and physical examinations. However, imaging can be helpful when intact brachialis function can compensate for a completely torn tendon. MRI is also useful in the setting of a complete tear to locate the torn tendon stump, and assess the degree of retraction for tendon retrieval^7,8 and quality of the tendon stump for repair. For associated rupture of the lacertus, the degree of proximal tendon retraction can be significant (Figures 1A, 1B). 

Continue to: Partial distal bicep tears...

MRI is useful in assessing the distal biceps tendon in the postoperative setting to evaluate the integrity of a repaired tendon. Cortical fixation button technique for repair creates minimal susceptibility artifacts on MRI. Postoperative MRI typically demonstrates a transverse hole drilled through the proximal radius at the site of the tuberosity with a cortical fixation button flush against the posterior radial cortex (Figures 8A-8D). 

ABSTRACT

Injuries to the distal biceps occur at the tendinous insertion at the radial tuberosity. Distal biceps injuries range from tendinosis to partial tears to non-retracted and retracted complete tears. Acute and chronic complete tears result from a tendinous avulsion at the radial tuberosity. Acute tears result from a strong force exerted on an eccentric biceps contraction, leading to tendon injury.

Distal biceps tendon injuries are uncommon (1.2 per 100,000 patients in one study).¹ An underlying degenerative component is involved in all distal biceps tendon tears and tendinosis.² Partial tears can be caused by the same mechanism or by no particular inciting event.³ Magnetic resonance imaging (MRI) is the optimal imaging modality for distal tendon tears because of its excellent specificity and sensitivity in the detection of complete tears.^4,5 Imaging also accurately diagnoses and characterizes partial tears and tendinosis.⁵ On MRI, fast spin-echo intermediate-weighted and T2-weighted or short tau inversion recovery (STIR) sequences are normally obtained to assess tendon integrity. Along with standard axial and sagittal views, the FABS (flexed elbow, abducted shoulder, supinated forearm) view is an important tool in the diagnosis of distal biceps tendon tears.⁶ The FABS view is obtained with the patient prone with the shoulder abducted 180° (above the head), with the elbow flexed to 90°, and the forearm supinated. This position allows a longitudinal view of along the entire length of the distal tendon.

Complete distal biceps tears can usually be diagnosed by history and physical examinations. However, imaging can be helpful when intact brachialis function can compensate for a completely torn tendon. MRI is also useful in the setting of a complete tear to locate the torn tendon stump, and assess the degree of retraction for tendon retrieval^7,8 and quality of the tendon stump for repair. For associated rupture of the lacertus, the degree of proximal tendon retraction can be significant (Figures 1A, 1B). 

Continue to: Partial distal bicep tears...

MRI is useful in assessing the distal biceps tendon in the postoperative setting to evaluate the integrity of a repaired tendon. Cortical fixation button technique for repair creates minimal susceptibility artifacts on MRI. Postoperative MRI typically demonstrates a transverse hole drilled through the proximal radius at the site of the tuberosity with a cortical fixation button flush against the posterior radial cortex (Figures 8A-8D). 

ABSTRACT

Injuries to the distal biceps occur at the tendinous insertion at the radial tuberosity. Distal biceps injuries range from tendinosis to partial tears to non-retracted and retracted complete tears. Acute and chronic complete tears result from a tendinous avulsion at the radial tuberosity. Acute tears result from a strong force exerted on an eccentric biceps contraction, leading to tendon injury.

Distal biceps tendon injuries are uncommon (1.2 per 100,000 patients in one study).¹ An underlying degenerative component is involved in all distal biceps tendon tears and tendinosis.² Partial tears can be caused by the same mechanism or by no particular inciting event.³ Magnetic resonance imaging (MRI) is the optimal imaging modality for distal tendon tears because of its excellent specificity and sensitivity in the detection of complete tears.^4,5 Imaging also accurately diagnoses and characterizes partial tears and tendinosis.⁵ On MRI, fast spin-echo intermediate-weighted and T2-weighted or short tau inversion recovery (STIR) sequences are normally obtained to assess tendon integrity. Along with standard axial and sagittal views, the FABS (flexed elbow, abducted shoulder, supinated forearm) view is an important tool in the diagnosis of distal biceps tendon tears.⁶ The FABS view is obtained with the patient prone with the shoulder abducted 180° (above the head), with the elbow flexed to 90°, and the forearm supinated. This position allows a longitudinal view of along the entire length of the distal tendon.

Complete distal biceps tears can usually be diagnosed by history and physical examinations. However, imaging can be helpful when intact brachialis function can compensate for a completely torn tendon. MRI is also useful in the setting of a complete tear to locate the torn tendon stump, and assess the degree of retraction for tendon retrieval^7,8 and quality of the tendon stump for repair. For associated rupture of the lacertus, the degree of proximal tendon retraction can be significant (Figures 1A, 1B). 

Continue to: Partial distal bicep tears...

MRI is useful in assessing the distal biceps tendon in the postoperative setting to evaluate the integrity of a repaired tendon. Cortical fixation button technique for repair creates minimal susceptibility artifacts on MRI. Postoperative MRI typically demonstrates a transverse hole drilled through the proximal radius at the site of the tuberosity with a cortical fixation button flush against the posterior radial cortex (Figures 8A-8D). 

ABSTRACT

Lesser tuberosity osteotomy (LTO) and subscapularis tenotomy (ST) are used for takedown of the subscapularis during shoulder arthroplasty. LTO offers the theoretical but unproven benefit of improved healing and function of the subscapularis. However, humeral stem subsidence and loosening may be greater when osteotomy is performed, which may compromise functional outcomes. Our hypothesis is that no difference in proximal collar press-fit humeral stem subsidence or loosening exists, with no impairment of functional outcomes using the LTO technique.

During the surgical approach for total shoulder arthroplasty (TSA), the subscapularis is taken down for adequate exposure to the glenohumeral joint. Various methods are available for taking down the subscapularis, including lesser tuberosity osteotomy (LTO) and a subscapularis tenotomy (ST). LTO offers the theoretical but unproven benefit of improved healing and function of the subscapularis secondary to bone-to-bone healing. One concern, however, is that humeral stem subsidence may be greater when an osteotomy is performed owing to compromise of metaphyseal cortical bone, which may compromise functional outcomes. The humeral stem design may also influence subsidence when metaphyseal bone proximally is compromised. This is a concern in both metaphyseal and diaphyseal fitting stems. Metaphyseal collars on diaphyseal fitting stems rely on adequate bone stock in the metaphysis to provide the additional support needed. Also, posterior subluxation remains a challenge in shoulder arthroplasty. The integrity of the subscapularis is important in prevention of posterior subluxation.¹ To our knowledge, no study to date has directly compared differences in humeral stem subsidence, loosening, or posterior subluxation between LTO and ST techniques with any humeral stem design. Our hypothesis is that no difference in proximal collar press-fit humeral stem subsidence or loosening exists, with no impairment of functional outcomes using the LTO technique. We also hypothesize that no difference in posterior subluxation exists between LTO and ST techniques.

MATERIALS AND METHODS

INCLUSION CRITERIA

Consecutive patients with a minimum of 12 months of radiographic follow-up were selected from 2007 to 2010 after TSA was performed by 1 of the senior authors (Dr. Miller and Dr. Voloshin). Study patients underwent primary TSA for primary osteoarthritis or rheumatoid arthritis.

EXCLUSION CRITERIA

Patients were excluded if they underwent TSA for posttraumatic glenohumeral arthritis, hemiarthroplasty, or osteonecrosis. Patients were also excluded if a rotator cuff tear was discovered intraoperatively or if they had a history of a rotator cuff repair. Additional exclusion criteria included postoperative trauma to the operative shoulder, postoperative infection, extensive documentation of chronic pain, and underlying neurologic disorder (eg, Parkinson disease, dystonia). Patients with a history of diabetes mellitus were not excluded.

SURGICAL TECHNIQUE

All patients underwent TSA via a deltopectoral approach in a modified beach chair position. Biceps tendons were tenodesed at the level of the pectoralis major. All patients received the same proximal collar press-fit implant (Bigliani-Flatow; Zimmer Biomet). These stems provide rotational stability in the metaphyseal segment via fins, vertical stability with the proximal collar, and distal fixation via an interference fit. All parts of the procedure were performed in similar fashion with the exception of ST vs LTO (Figures 1A-1D). 

Continue to: LTO was performed as the primary...

LESSER TUBEROSITY OSTEOTOMY

LTO was performed as the primary or preferred technique of 1 surgeon. After completion of the biceps tenodesis, the lesser tuberosity is reflected off with the subscapularis intact using an osteotome. After placement of the press-fit humeral stem, the LTO is repaired using No. 5 Ethibond Excel sutures (Ethicon) passed through previously created bone tunnels in the greater tuberosity. These sutures are tied over metal buttons over the lateral cortex of the greater tuberosity. Last, the lateral corner of the rotator interval is repaired using a single No. 2 FiberWire (Arthrex).²

SUBSCAPULARIS TENOTOMY

ST is the preferred surgical technique of the second surgeon. After a biceps tenodesis, the subscapularis tendon is released from the lesser tuberosity at the margin of the bicipital groove. Through careful dissection, a single flap including the underlying capsule is created and reflected medially to the level of the coracoid. After placement of the press-fit humeral stem and humeral head, the subscapularis is repaired back in place through previous bone tunnels and with a No. 5 Ethibond Excel suture under the appropriate tension. Then, the lateral corner of the rotator interval is closed using a single No. 2 Ethibond Excel suture in a figure-of-eight fashion.²

RADIOGRAPHIC ANALYSIS

The primary variables analyzed were subsidence and loosening. Additional variables, including humeral-acromial distance (HAD) and subluxation index, were also analyzed to assess for any additional impact caused by subsidence or loosening.³ All radiographic measurements were taken from the Grashey (true anteroposterior) view, except subluxation index, which was calculated using the axillary view. All radiographic measurements were completed by 3 independent reviewers. All radiographs were completed in a consistent manner according to postoperative protocols.

HAD was measured preoperatively, immediately postoperatively, and at final follow-up at a minimum of 1 year. The HAD was measured from the lowest point on the acromion to the humerus using a perpendicular line (Figure 2).

Subsidence of the prosthesis was calculated by determining the difference between immediate postoperative heights of the prosthesis in comparison to the value of the final follow-up films. To calculate the height, 2 lines were drawn, 1 line was drawn perpendicular to the top of the prosthetic head and 1 perpendicular to the top of the greater tuberosity (Figure 3). 

Continue to: Posterior subluxation is indicated...

The humeral stems were evaluated for loosening by assessing for lucency on final radiographic follow-up films. These were evaluated in a zonal fashion as demonstrated by Sanchez-Sotelo and colleagues⁴ and in Figure 5. 

FUNCTIONAL OUTCOME EVALUATION

Before clinical evaluation, each study patient completed the Western Ontario Osteoarthritis of the Shoulder (WOOS) index; the Disabilities of the Hand, Arm and Shoulder (DASH) questionnaire, and the pain and function sections of the Constant score. The functional outcomes scores were captured postoperatively from October to November 2011. The WOOS is a validated outcome measure specific to osteoarthritis of the shoulder and has been used in prior studies evaluating outcomes of TSA.^5-7 Previous studies have determined that the minimal clinically important difference for the WOOS score is 15 on a normalized 0 to 100 scale (100 being the best). The DASH score is a validated outcome measure for disorders of the upper extremity but is not specific to osteoarthritis of the shoulder.⁸ The Constant score is a validated outcome measure for a number of shoulder disorders, including TSA.^9,10

STATISTICAL ANALYSIS

Statistical analyses were completed by a trained biostatistician. A power analysis was calculated using the noninferiority test to determine if adequate data had been obtained for this study. This was calculated by using previously accepted data demonstrating a statistically significant difference for subsidence and HAD. The data from these studies were used to make assumptions regarding accepted standard deviations and noninferiority margins, as calculated from the mean values of the 2 groups analyzed in each respective study.^4,11 This analysis demonstrated power of 0.97 and 0.85 for the subsidence and HAD, respectively, given the current sample sizes. Intraclass coefficients were calculated to evaluate the measurements obtained during the radiographic analysis to determine the interrater agreement. Two samples’ t tests were calculated for the variables analyzed, along with P values and means.

RESULTS

DEMOGRAPHICS

A total of 51 consecutive patients were retrospectively selected for analysis. Of these, 16 patients were excluded from the study because they had <9 months of radiographic follow-up and were unavailable for further follow-up evaluation. Of the remaining 35 patients available for analysis, 4 patients had bilateral TSA, providing 39 shoulders for evaluation. Demographic characteristics of the study cohort are reported in Table 1.

  Fifteen patients underwent LTO, and 24 underwent ST. One patient underwent a tenotomy of the right shoulder and LTO of the left shoulder. Three LTOs were performed by the surgeon who primarily performed ST, owing to potential benefits of LTO. He eventually returned to his preferred technique of ST because of surgeon preference. Three ST procedures were completed by the surgeon who typically performed LTO at the start of the series prior to establishing LTO as his preferred technique. There was no significant difference between the study populations in terms of age, follow-up, male-to-female ratio, hand dominance, and primary diagnosis of osteoarthritis vs rheumatoid arthritis.

Continue to: There was no significant difference...

RADIOGRAPHIC DATA

There was no significant difference in preoperative HAD between the LTO and ST groups (9.5 ± 2.4 mm vs 10.9 ± 2.7 mm, P = .11). The immediate postoperative HAD was statistically significant between the LTO and ST groups (11.9 ± 3.7 mm vs 15.9 ± 4.5 mm, P = .005). There was as statistically significant difference noted in the final follow-up films between the LTO and ST groups (11.8 ± 3.2 mm vs 14.5 ± 3.9 mm, P = .025) (Table 2). 

Abbreviations: LTO, lesser tuberosity osteotomy; ST, subscapularis tenotomy.

There were no statistically significant differences found in subsidence between LTO and ST groups at final follow-up (2.8 mm ± 3.1 mm vs 2.5 mm ± 3.1 mm, P = .72) (Table 2). No statistically significant difference was noted in the subluxation index between the LTO and ST groups (0.55% ± .06% vs 0.54% ± 0.07%, P = .45), but there was a statistically significant difference noted postoperatively between the LTO and ST groups (0.55% ± 0.09% vs .48% ± 0.05%, P = .015) (Table 2).

Two stems were noted to have lucent lines >2 mm, both within the ST cohort. Each had 1 stem zone >2 mm, 1 in zone 7, and 1 in zone 4. No statistically significant difference was identified between the LTO and ST groups (0/15 vs 2/24, P = .51) (Table 2).

FUNCTIONAL OUTCOMES

Study patients were evaluated using functional outcome scores, including the Constant, WOOS, and DASH scores (Table 3). 

Abbreviations: DASH, disabilities of the arm, shoulder and hand; WOOS, Western Ontario Osteoarthritis of the Shoulder.

No statistically significant differences were noted in the DASH scores (8.4 ± 6.6 vs 13.8 ± 4.9, P = .13) or Constant scores (83.3 ± 9.1 vs 81.8 ± 10.1, P = .64) between the LTO and ST cohorts. There was a statistically significant difference between the WOOS scores (93.3 ± 5.3 vs 81.5 ± 20.8, P = .013). Because separate radiographic reviews were done by 3 independent personnel at 3 different times, it was important to ensure agreement among the reviewers. This was compared using the intraclass correlation coefficients. In the statistical analysis completed, the intraclass coefficients showed the 3 reviewers agreed with each other throughout the radiographic analysis (Table 4).

Abbreviations: CI, confidence interval; HAD, humeral acromial distance; ICC, intraclass correlation coefficient; SI, subluxation index.

DISCUSSION

At final follow-up, we identified no statistically significant difference between the LTO and ST patients in subsidence, lucent lines >2 mm, or functional outcomes (Constant and DASH scores) in patients who underwent TSA with the same proximal collar press-fit humeral stem. In regard to the functional outcome scores, although the WOOS score was statistically significant (P = .013) between the LTO and ST cohorts, we do not feel that this is clinically relevant because it does not reach the minimal clinically important difference threshold of 15 points.⁸

A statistically significant difference was noted in postoperative subluxation index but was not clinically relevant, because the values between the LTO and ST groups (0.55 vs 0.48) still showed a centered humeral head. Gerber and colleagues³ discussed using a value of 0.65 as a measure of posterior humeral head subluxation, whereas Walch and colleagues¹² defined posterior humeral head subluxation as a value >0.55. On the basis of these numbers, the values obtained in this study demonstrated that the postoperative values were still centered on the glenoid, and therefore were not clinically significant.^3,12

Continue to: In regard to HAD, there...

Studies have shown a concern regarding the integrity of the subscapularis after tenotomy or peel used in TSA with abnormal subscapularis function.^14,15 Miller and colleagues¹⁵ reported 41 patients, nearly two-thirds, of whom described subscapularis dysfunction. Those authors’ response to the poor clinical outcomes was to remove a fleck of bone with the tendon to achieve “bone-to-bone” healing.¹⁴ Gerber and colleagues¹⁶ reported on a series of patients using LTO and repair in TSA with 75% and 89% intact subscapularis function on clinical testing.¹⁶ Studies by Qureshi and colleagues¹⁷ and Scalise and colleagues¹⁸ showed similar results after LTO. Biomechanical studies have shown mixed results. Ponce and colleagues¹⁹ showed biomechanically superior results for LTO in comparison to the various repair techniques for ST. In another study, Giuseffi and colleagues²⁰ showed no difference in LTO vs ST during biomechanical testing. In response to the increased concern regarding subscapularis integrity, Caplan and colleagues²¹ reported on 45 arthroplasties in 43 patients with improved postoperative testing with intact subscapularis testing in 90% to 100% of patients. A level 1 randomized control trial conducted by Lapner and colleagues²² did not demonstrate any clear clinical advantage of LTO vs ST. Controversy still exists regarding which is the preferred technique for TSA.

Sanchez-Sotelo and colleagues⁴ evaluated uncemented humeral components in 72 patients who underwent TSA. They found a humeral component was at risk for loosening if a radiolucent line ≥2 mm was present in at least 3 radiographic zones. They also evaluated tilt or subsidence by measurement and whether the components were observed to have changed. Their measured values correlated with their observed values. That study provided a benchmark for evaluation of loosening and subsidence used during this study.⁴ Although radiographic follow-up is limited in this study, we feel that any potential subsidence secondary to use of the LTO technique would be radiographically apparent at 1 year. There were 16 patients without adequate radiographic follow-up included in the study. However, we feel that this was not a large concern, because the study was adequately powered with the patients available to determine a difference based on subsidence.

CONCLUSION

We found no difference in subsidence, lucent lines >2 mm, posterior subluxation, and the Constant and DASH functional outcome scores when we compared TSA performed by a LTO with an ST technique with proximal collar press-fit humeral stem. These data cannot be extrapolated to metaphyseal fit stems, which may exhibit different settling characteristics in the setting of the LTO technique.

This paper will be judged for the Resident Writer’s Award.

ABSTRACT

Lesser tuberosity osteotomy (LTO) and subscapularis tenotomy (ST) are used for takedown of the subscapularis during shoulder arthroplasty. LTO offers the theoretical but unproven benefit of improved healing and function of the subscapularis. However, humeral stem subsidence and loosening may be greater when osteotomy is performed, which may compromise functional outcomes. Our hypothesis is that no difference in proximal collar press-fit humeral stem subsidence or loosening exists, with no impairment of functional outcomes using the LTO technique.

During the surgical approach for total shoulder arthroplasty (TSA), the subscapularis is taken down for adequate exposure to the glenohumeral joint. Various methods are available for taking down the subscapularis, including lesser tuberosity osteotomy (LTO) and a subscapularis tenotomy (ST). LTO offers the theoretical but unproven benefit of improved healing and function of the subscapularis secondary to bone-to-bone healing. One concern, however, is that humeral stem subsidence may be greater when an osteotomy is performed owing to compromise of metaphyseal cortical bone, which may compromise functional outcomes. The humeral stem design may also influence subsidence when metaphyseal bone proximally is compromised. This is a concern in both metaphyseal and diaphyseal fitting stems. Metaphyseal collars on diaphyseal fitting stems rely on adequate bone stock in the metaphysis to provide the additional support needed. Also, posterior subluxation remains a challenge in shoulder arthroplasty. The integrity of the subscapularis is important in prevention of posterior subluxation.¹ To our knowledge, no study to date has directly compared differences in humeral stem subsidence, loosening, or posterior subluxation between LTO and ST techniques with any humeral stem design. Our hypothesis is that no difference in proximal collar press-fit humeral stem subsidence or loosening exists, with no impairment of functional outcomes using the LTO technique. We also hypothesize that no difference in posterior subluxation exists between LTO and ST techniques.

MATERIALS AND METHODS

INCLUSION CRITERIA

Consecutive patients with a minimum of 12 months of radiographic follow-up were selected from 2007 to 2010 after TSA was performed by 1 of the senior authors (Dr. Miller and Dr. Voloshin). Study patients underwent primary TSA for primary osteoarthritis or rheumatoid arthritis.

EXCLUSION CRITERIA

Patients were excluded if they underwent TSA for posttraumatic glenohumeral arthritis, hemiarthroplasty, or osteonecrosis. Patients were also excluded if a rotator cuff tear was discovered intraoperatively or if they had a history of a rotator cuff repair. Additional exclusion criteria included postoperative trauma to the operative shoulder, postoperative infection, extensive documentation of chronic pain, and underlying neurologic disorder (eg, Parkinson disease, dystonia). Patients with a history of diabetes mellitus were not excluded.

SURGICAL TECHNIQUE

All patients underwent TSA via a deltopectoral approach in a modified beach chair position. Biceps tendons were tenodesed at the level of the pectoralis major. All patients received the same proximal collar press-fit implant (Bigliani-Flatow; Zimmer Biomet). These stems provide rotational stability in the metaphyseal segment via fins, vertical stability with the proximal collar, and distal fixation via an interference fit. All parts of the procedure were performed in similar fashion with the exception of ST vs LTO (Figures 1A-1D). 

Continue to: LTO was performed as the primary...

LESSER TUBEROSITY OSTEOTOMY

LTO was performed as the primary or preferred technique of 1 surgeon. After completion of the biceps tenodesis, the lesser tuberosity is reflected off with the subscapularis intact using an osteotome. After placement of the press-fit humeral stem, the LTO is repaired using No. 5 Ethibond Excel sutures (Ethicon) passed through previously created bone tunnels in the greater tuberosity. These sutures are tied over metal buttons over the lateral cortex of the greater tuberosity. Last, the lateral corner of the rotator interval is repaired using a single No. 2 FiberWire (Arthrex).²

SUBSCAPULARIS TENOTOMY

ST is the preferred surgical technique of the second surgeon. After a biceps tenodesis, the subscapularis tendon is released from the lesser tuberosity at the margin of the bicipital groove. Through careful dissection, a single flap including the underlying capsule is created and reflected medially to the level of the coracoid. After placement of the press-fit humeral stem and humeral head, the subscapularis is repaired back in place through previous bone tunnels and with a No. 5 Ethibond Excel suture under the appropriate tension. Then, the lateral corner of the rotator interval is closed using a single No. 2 Ethibond Excel suture in a figure-of-eight fashion.²

RADIOGRAPHIC ANALYSIS

The primary variables analyzed were subsidence and loosening. Additional variables, including humeral-acromial distance (HAD) and subluxation index, were also analyzed to assess for any additional impact caused by subsidence or loosening.³ All radiographic measurements were taken from the Grashey (true anteroposterior) view, except subluxation index, which was calculated using the axillary view. All radiographic measurements were completed by 3 independent reviewers. All radiographs were completed in a consistent manner according to postoperative protocols.

HAD was measured preoperatively, immediately postoperatively, and at final follow-up at a minimum of 1 year. The HAD was measured from the lowest point on the acromion to the humerus using a perpendicular line (Figure 2).

Subsidence of the prosthesis was calculated by determining the difference between immediate postoperative heights of the prosthesis in comparison to the value of the final follow-up films. To calculate the height, 2 lines were drawn, 1 line was drawn perpendicular to the top of the prosthetic head and 1 perpendicular to the top of the greater tuberosity (Figure 3). 

Continue to: Posterior subluxation is indicated...

The humeral stems were evaluated for loosening by assessing for lucency on final radiographic follow-up films. These were evaluated in a zonal fashion as demonstrated by Sanchez-Sotelo and colleagues⁴ and in Figure 5. 

FUNCTIONAL OUTCOME EVALUATION

Before clinical evaluation, each study patient completed the Western Ontario Osteoarthritis of the Shoulder (WOOS) index; the Disabilities of the Hand, Arm and Shoulder (DASH) questionnaire, and the pain and function sections of the Constant score. The functional outcomes scores were captured postoperatively from October to November 2011. The WOOS is a validated outcome measure specific to osteoarthritis of the shoulder and has been used in prior studies evaluating outcomes of TSA.^5-7 Previous studies have determined that the minimal clinically important difference for the WOOS score is 15 on a normalized 0 to 100 scale (100 being the best). The DASH score is a validated outcome measure for disorders of the upper extremity but is not specific to osteoarthritis of the shoulder.⁸ The Constant score is a validated outcome measure for a number of shoulder disorders, including TSA.^9,10

STATISTICAL ANALYSIS

Statistical analyses were completed by a trained biostatistician. A power analysis was calculated using the noninferiority test to determine if adequate data had been obtained for this study. This was calculated by using previously accepted data demonstrating a statistically significant difference for subsidence and HAD. The data from these studies were used to make assumptions regarding accepted standard deviations and noninferiority margins, as calculated from the mean values of the 2 groups analyzed in each respective study.^4,11 This analysis demonstrated power of 0.97 and 0.85 for the subsidence and HAD, respectively, given the current sample sizes. Intraclass coefficients were calculated to evaluate the measurements obtained during the radiographic analysis to determine the interrater agreement. Two samples’ t tests were calculated for the variables analyzed, along with P values and means.

RESULTS

DEMOGRAPHICS

A total of 51 consecutive patients were retrospectively selected for analysis. Of these, 16 patients were excluded from the study because they had <9 months of radiographic follow-up and were unavailable for further follow-up evaluation. Of the remaining 35 patients available for analysis, 4 patients had bilateral TSA, providing 39 shoulders for evaluation. Demographic characteristics of the study cohort are reported in Table 1.

  Fifteen patients underwent LTO, and 24 underwent ST. One patient underwent a tenotomy of the right shoulder and LTO of the left shoulder. Three LTOs were performed by the surgeon who primarily performed ST, owing to potential benefits of LTO. He eventually returned to his preferred technique of ST because of surgeon preference. Three ST procedures were completed by the surgeon who typically performed LTO at the start of the series prior to establishing LTO as his preferred technique. There was no significant difference between the study populations in terms of age, follow-up, male-to-female ratio, hand dominance, and primary diagnosis of osteoarthritis vs rheumatoid arthritis.

Continue to: There was no significant difference...

RADIOGRAPHIC DATA

There was no significant difference in preoperative HAD between the LTO and ST groups (9.5 ± 2.4 mm vs 10.9 ± 2.7 mm, P = .11). The immediate postoperative HAD was statistically significant between the LTO and ST groups (11.9 ± 3.7 mm vs 15.9 ± 4.5 mm, P = .005). There was as statistically significant difference noted in the final follow-up films between the LTO and ST groups (11.8 ± 3.2 mm vs 14.5 ± 3.9 mm, P = .025) (Table 2). 

Abbreviations: LTO, lesser tuberosity osteotomy; ST, subscapularis tenotomy.

There were no statistically significant differences found in subsidence between LTO and ST groups at final follow-up (2.8 mm ± 3.1 mm vs 2.5 mm ± 3.1 mm, P = .72) (Table 2). No statistically significant difference was noted in the subluxation index between the LTO and ST groups (0.55% ± .06% vs 0.54% ± 0.07%, P = .45), but there was a statistically significant difference noted postoperatively between the LTO and ST groups (0.55% ± 0.09% vs .48% ± 0.05%, P = .015) (Table 2).

Two stems were noted to have lucent lines >2 mm, both within the ST cohort. Each had 1 stem zone >2 mm, 1 in zone 7, and 1 in zone 4. No statistically significant difference was identified between the LTO and ST groups (0/15 vs 2/24, P = .51) (Table 2).

FUNCTIONAL OUTCOMES

Study patients were evaluated using functional outcome scores, including the Constant, WOOS, and DASH scores (Table 3). 

Abbreviations: DASH, disabilities of the arm, shoulder and hand; WOOS, Western Ontario Osteoarthritis of the Shoulder.

No statistically significant differences were noted in the DASH scores (8.4 ± 6.6 vs 13.8 ± 4.9, P = .13) or Constant scores (83.3 ± 9.1 vs 81.8 ± 10.1, P = .64) between the LTO and ST cohorts. There was a statistically significant difference between the WOOS scores (93.3 ± 5.3 vs 81.5 ± 20.8, P = .013). Because separate radiographic reviews were done by 3 independent personnel at 3 different times, it was important to ensure agreement among the reviewers. This was compared using the intraclass correlation coefficients. In the statistical analysis completed, the intraclass coefficients showed the 3 reviewers agreed with each other throughout the radiographic analysis (Table 4).

Abbreviations: CI, confidence interval; HAD, humeral acromial distance; ICC, intraclass correlation coefficient; SI, subluxation index.

DISCUSSION

At final follow-up, we identified no statistically significant difference between the LTO and ST patients in subsidence, lucent lines >2 mm, or functional outcomes (Constant and DASH scores) in patients who underwent TSA with the same proximal collar press-fit humeral stem. In regard to the functional outcome scores, although the WOOS score was statistically significant (P = .013) between the LTO and ST cohorts, we do not feel that this is clinically relevant because it does not reach the minimal clinically important difference threshold of 15 points.⁸

A statistically significant difference was noted in postoperative subluxation index but was not clinically relevant, because the values between the LTO and ST groups (0.55 vs 0.48) still showed a centered humeral head. Gerber and colleagues³ discussed using a value of 0.65 as a measure of posterior humeral head subluxation, whereas Walch and colleagues¹² defined posterior humeral head subluxation as a value >0.55. On the basis of these numbers, the values obtained in this study demonstrated that the postoperative values were still centered on the glenoid, and therefore were not clinically significant.^3,12

Continue to: In regard to HAD, there...

Studies have shown a concern regarding the integrity of the subscapularis after tenotomy or peel used in TSA with abnormal subscapularis function.^14,15 Miller and colleagues¹⁵ reported 41 patients, nearly two-thirds, of whom described subscapularis dysfunction. Those authors’ response to the poor clinical outcomes was to remove a fleck of bone with the tendon to achieve “bone-to-bone” healing.¹⁴ Gerber and colleagues¹⁶ reported on a series of patients using LTO and repair in TSA with 75% and 89% intact subscapularis function on clinical testing.¹⁶ Studies by Qureshi and colleagues¹⁷ and Scalise and colleagues¹⁸ showed similar results after LTO. Biomechanical studies have shown mixed results. Ponce and colleagues¹⁹ showed biomechanically superior results for LTO in comparison to the various repair techniques for ST. In another study, Giuseffi and colleagues²⁰ showed no difference in LTO vs ST during biomechanical testing. In response to the increased concern regarding subscapularis integrity, Caplan and colleagues²¹ reported on 45 arthroplasties in 43 patients with improved postoperative testing with intact subscapularis testing in 90% to 100% of patients. A level 1 randomized control trial conducted by Lapner and colleagues²² did not demonstrate any clear clinical advantage of LTO vs ST. Controversy still exists regarding which is the preferred technique for TSA.

Sanchez-Sotelo and colleagues⁴ evaluated uncemented humeral components in 72 patients who underwent TSA. They found a humeral component was at risk for loosening if a radiolucent line ≥2 mm was present in at least 3 radiographic zones. They also evaluated tilt or subsidence by measurement and whether the components were observed to have changed. Their measured values correlated with their observed values. That study provided a benchmark for evaluation of loosening and subsidence used during this study.⁴ Although radiographic follow-up is limited in this study, we feel that any potential subsidence secondary to use of the LTO technique would be radiographically apparent at 1 year. There were 16 patients without adequate radiographic follow-up included in the study. However, we feel that this was not a large concern, because the study was adequately powered with the patients available to determine a difference based on subsidence.

CONCLUSION

We found no difference in subsidence, lucent lines >2 mm, posterior subluxation, and the Constant and DASH functional outcome scores when we compared TSA performed by a LTO with an ST technique with proximal collar press-fit humeral stem. These data cannot be extrapolated to metaphyseal fit stems, which may exhibit different settling characteristics in the setting of the LTO technique.

This paper will be judged for the Resident Writer’s Award.

ABSTRACT

Lesser tuberosity osteotomy (LTO) and subscapularis tenotomy (ST) are used for takedown of the subscapularis during shoulder arthroplasty. LTO offers the theoretical but unproven benefit of improved healing and function of the subscapularis. However, humeral stem subsidence and loosening may be greater when osteotomy is performed, which may compromise functional outcomes. Our hypothesis is that no difference in proximal collar press-fit humeral stem subsidence or loosening exists, with no impairment of functional outcomes using the LTO technique.

During the surgical approach for total shoulder arthroplasty (TSA), the subscapularis is taken down for adequate exposure to the glenohumeral joint. Various methods are available for taking down the subscapularis, including lesser tuberosity osteotomy (LTO) and a subscapularis tenotomy (ST). LTO offers the theoretical but unproven benefit of improved healing and function of the subscapularis secondary to bone-to-bone healing. One concern, however, is that humeral stem subsidence may be greater when an osteotomy is performed owing to compromise of metaphyseal cortical bone, which may compromise functional outcomes. The humeral stem design may also influence subsidence when metaphyseal bone proximally is compromised. This is a concern in both metaphyseal and diaphyseal fitting stems. Metaphyseal collars on diaphyseal fitting stems rely on adequate bone stock in the metaphysis to provide the additional support needed. Also, posterior subluxation remains a challenge in shoulder arthroplasty. The integrity of the subscapularis is important in prevention of posterior subluxation.¹ To our knowledge, no study to date has directly compared differences in humeral stem subsidence, loosening, or posterior subluxation between LTO and ST techniques with any humeral stem design. Our hypothesis is that no difference in proximal collar press-fit humeral stem subsidence or loosening exists, with no impairment of functional outcomes using the LTO technique. We also hypothesize that no difference in posterior subluxation exists between LTO and ST techniques.

MATERIALS AND METHODS

INCLUSION CRITERIA

Consecutive patients with a minimum of 12 months of radiographic follow-up were selected from 2007 to 2010 after TSA was performed by 1 of the senior authors (Dr. Miller and Dr. Voloshin). Study patients underwent primary TSA for primary osteoarthritis or rheumatoid arthritis.

EXCLUSION CRITERIA

Patients were excluded if they underwent TSA for posttraumatic glenohumeral arthritis, hemiarthroplasty, or osteonecrosis. Patients were also excluded if a rotator cuff tear was discovered intraoperatively or if they had a history of a rotator cuff repair. Additional exclusion criteria included postoperative trauma to the operative shoulder, postoperative infection, extensive documentation of chronic pain, and underlying neurologic disorder (eg, Parkinson disease, dystonia). Patients with a history of diabetes mellitus were not excluded.

SURGICAL TECHNIQUE

All patients underwent TSA via a deltopectoral approach in a modified beach chair position. Biceps tendons were tenodesed at the level of the pectoralis major. All patients received the same proximal collar press-fit implant (Bigliani-Flatow; Zimmer Biomet). These stems provide rotational stability in the metaphyseal segment via fins, vertical stability with the proximal collar, and distal fixation via an interference fit. All parts of the procedure were performed in similar fashion with the exception of ST vs LTO (Figures 1A-1D). 

Continue to: LTO was performed as the primary...

LESSER TUBEROSITY OSTEOTOMY

LTO was performed as the primary or preferred technique of 1 surgeon. After completion of the biceps tenodesis, the lesser tuberosity is reflected off with the subscapularis intact using an osteotome. After placement of the press-fit humeral stem, the LTO is repaired using No. 5 Ethibond Excel sutures (Ethicon) passed through previously created bone tunnels in the greater tuberosity. These sutures are tied over metal buttons over the lateral cortex of the greater tuberosity. Last, the lateral corner of the rotator interval is repaired using a single No. 2 FiberWire (Arthrex).²

SUBSCAPULARIS TENOTOMY

ST is the preferred surgical technique of the second surgeon. After a biceps tenodesis, the subscapularis tendon is released from the lesser tuberosity at the margin of the bicipital groove. Through careful dissection, a single flap including the underlying capsule is created and reflected medially to the level of the coracoid. After placement of the press-fit humeral stem and humeral head, the subscapularis is repaired back in place through previous bone tunnels and with a No. 5 Ethibond Excel suture under the appropriate tension. Then, the lateral corner of the rotator interval is closed using a single No. 2 Ethibond Excel suture in a figure-of-eight fashion.²

RADIOGRAPHIC ANALYSIS

The primary variables analyzed were subsidence and loosening. Additional variables, including humeral-acromial distance (HAD) and subluxation index, were also analyzed to assess for any additional impact caused by subsidence or loosening.³ All radiographic measurements were taken from the Grashey (true anteroposterior) view, except subluxation index, which was calculated using the axillary view. All radiographic measurements were completed by 3 independent reviewers. All radiographs were completed in a consistent manner according to postoperative protocols.

HAD was measured preoperatively, immediately postoperatively, and at final follow-up at a minimum of 1 year. The HAD was measured from the lowest point on the acromion to the humerus using a perpendicular line (Figure 2).

Subsidence of the prosthesis was calculated by determining the difference between immediate postoperative heights of the prosthesis in comparison to the value of the final follow-up films. To calculate the height, 2 lines were drawn, 1 line was drawn perpendicular to the top of the prosthetic head and 1 perpendicular to the top of the greater tuberosity (Figure 3). 

Continue to: Posterior subluxation is indicated...

The humeral stems were evaluated for loosening by assessing for lucency on final radiographic follow-up films. These were evaluated in a zonal fashion as demonstrated by Sanchez-Sotelo and colleagues⁴ and in Figure 5. 

FUNCTIONAL OUTCOME EVALUATION

Before clinical evaluation, each study patient completed the Western Ontario Osteoarthritis of the Shoulder (WOOS) index; the Disabilities of the Hand, Arm and Shoulder (DASH) questionnaire, and the pain and function sections of the Constant score. The functional outcomes scores were captured postoperatively from October to November 2011. The WOOS is a validated outcome measure specific to osteoarthritis of the shoulder and has been used in prior studies evaluating outcomes of TSA.^5-7 Previous studies have determined that the minimal clinically important difference for the WOOS score is 15 on a normalized 0 to 100 scale (100 being the best). The DASH score is a validated outcome measure for disorders of the upper extremity but is not specific to osteoarthritis of the shoulder.⁸ The Constant score is a validated outcome measure for a number of shoulder disorders, including TSA.^9,10

STATISTICAL ANALYSIS

Statistical analyses were completed by a trained biostatistician. A power analysis was calculated using the noninferiority test to determine if adequate data had been obtained for this study. This was calculated by using previously accepted data demonstrating a statistically significant difference for subsidence and HAD. The data from these studies were used to make assumptions regarding accepted standard deviations and noninferiority margins, as calculated from the mean values of the 2 groups analyzed in each respective study.^4,11 This analysis demonstrated power of 0.97 and 0.85 for the subsidence and HAD, respectively, given the current sample sizes. Intraclass coefficients were calculated to evaluate the measurements obtained during the radiographic analysis to determine the interrater agreement. Two samples’ t tests were calculated for the variables analyzed, along with P values and means.

RESULTS

DEMOGRAPHICS

A total of 51 consecutive patients were retrospectively selected for analysis. Of these, 16 patients were excluded from the study because they had <9 months of radiographic follow-up and were unavailable for further follow-up evaluation. Of the remaining 35 patients available for analysis, 4 patients had bilateral TSA, providing 39 shoulders for evaluation. Demographic characteristics of the study cohort are reported in Table 1.

  Fifteen patients underwent LTO, and 24 underwent ST. One patient underwent a tenotomy of the right shoulder and LTO of the left shoulder. Three LTOs were performed by the surgeon who primarily performed ST, owing to potential benefits of LTO. He eventually returned to his preferred technique of ST because of surgeon preference. Three ST procedures were completed by the surgeon who typically performed LTO at the start of the series prior to establishing LTO as his preferred technique. There was no significant difference between the study populations in terms of age, follow-up, male-to-female ratio, hand dominance, and primary diagnosis of osteoarthritis vs rheumatoid arthritis.

Continue to: There was no significant difference...

RADIOGRAPHIC DATA

There was no significant difference in preoperative HAD between the LTO and ST groups (9.5 ± 2.4 mm vs 10.9 ± 2.7 mm, P = .11). The immediate postoperative HAD was statistically significant between the LTO and ST groups (11.9 ± 3.7 mm vs 15.9 ± 4.5 mm, P = .005). There was as statistically significant difference noted in the final follow-up films between the LTO and ST groups (11.8 ± 3.2 mm vs 14.5 ± 3.9 mm, P = .025) (Table 2). 

Abbreviations: LTO, lesser tuberosity osteotomy; ST, subscapularis tenotomy.

There were no statistically significant differences found in subsidence between LTO and ST groups at final follow-up (2.8 mm ± 3.1 mm vs 2.5 mm ± 3.1 mm, P = .72) (Table 2). No statistically significant difference was noted in the subluxation index between the LTO and ST groups (0.55% ± .06% vs 0.54% ± 0.07%, P = .45), but there was a statistically significant difference noted postoperatively between the LTO and ST groups (0.55% ± 0.09% vs .48% ± 0.05%, P = .015) (Table 2).

Two stems were noted to have lucent lines >2 mm, both within the ST cohort. Each had 1 stem zone >2 mm, 1 in zone 7, and 1 in zone 4. No statistically significant difference was identified between the LTO and ST groups (0/15 vs 2/24, P = .51) (Table 2).

FUNCTIONAL OUTCOMES

Study patients were evaluated using functional outcome scores, including the Constant, WOOS, and DASH scores (Table 3). 

Abbreviations: DASH, disabilities of the arm, shoulder and hand; WOOS, Western Ontario Osteoarthritis of the Shoulder.

No statistically significant differences were noted in the DASH scores (8.4 ± 6.6 vs 13.8 ± 4.9, P = .13) or Constant scores (83.3 ± 9.1 vs 81.8 ± 10.1, P = .64) between the LTO and ST cohorts. There was a statistically significant difference between the WOOS scores (93.3 ± 5.3 vs 81.5 ± 20.8, P = .013). Because separate radiographic reviews were done by 3 independent personnel at 3 different times, it was important to ensure agreement among the reviewers. This was compared using the intraclass correlation coefficients. In the statistical analysis completed, the intraclass coefficients showed the 3 reviewers agreed with each other throughout the radiographic analysis (Table 4).

Abbreviations: CI, confidence interval; HAD, humeral acromial distance; ICC, intraclass correlation coefficient; SI, subluxation index.

DISCUSSION

At final follow-up, we identified no statistically significant difference between the LTO and ST patients in subsidence, lucent lines >2 mm, or functional outcomes (Constant and DASH scores) in patients who underwent TSA with the same proximal collar press-fit humeral stem. In regard to the functional outcome scores, although the WOOS score was statistically significant (P = .013) between the LTO and ST cohorts, we do not feel that this is clinically relevant because it does not reach the minimal clinically important difference threshold of 15 points.⁸

A statistically significant difference was noted in postoperative subluxation index but was not clinically relevant, because the values between the LTO and ST groups (0.55 vs 0.48) still showed a centered humeral head. Gerber and colleagues³ discussed using a value of 0.65 as a measure of posterior humeral head subluxation, whereas Walch and colleagues¹² defined posterior humeral head subluxation as a value >0.55. On the basis of these numbers, the values obtained in this study demonstrated that the postoperative values were still centered on the glenoid, and therefore were not clinically significant.^3,12

Continue to: In regard to HAD, there...

Studies have shown a concern regarding the integrity of the subscapularis after tenotomy or peel used in TSA with abnormal subscapularis function.^14,15 Miller and colleagues¹⁵ reported 41 patients, nearly two-thirds, of whom described subscapularis dysfunction. Those authors’ response to the poor clinical outcomes was to remove a fleck of bone with the tendon to achieve “bone-to-bone” healing.¹⁴ Gerber and colleagues¹⁶ reported on a series of patients using LTO and repair in TSA with 75% and 89% intact subscapularis function on clinical testing.¹⁶ Studies by Qureshi and colleagues¹⁷ and Scalise and colleagues¹⁸ showed similar results after LTO. Biomechanical studies have shown mixed results. Ponce and colleagues¹⁹ showed biomechanically superior results for LTO in comparison to the various repair techniques for ST. In another study, Giuseffi and colleagues²⁰ showed no difference in LTO vs ST during biomechanical testing. In response to the increased concern regarding subscapularis integrity, Caplan and colleagues²¹ reported on 45 arthroplasties in 43 patients with improved postoperative testing with intact subscapularis testing in 90% to 100% of patients. A level 1 randomized control trial conducted by Lapner and colleagues²² did not demonstrate any clear clinical advantage of LTO vs ST. Controversy still exists regarding which is the preferred technique for TSA.

Sanchez-Sotelo and colleagues⁴ evaluated uncemented humeral components in 72 patients who underwent TSA. They found a humeral component was at risk for loosening if a radiolucent line ≥2 mm was present in at least 3 radiographic zones. They also evaluated tilt or subsidence by measurement and whether the components were observed to have changed. Their measured values correlated with their observed values. That study provided a benchmark for evaluation of loosening and subsidence used during this study.⁴ Although radiographic follow-up is limited in this study, we feel that any potential subsidence secondary to use of the LTO technique would be radiographically apparent at 1 year. There were 16 patients without adequate radiographic follow-up included in the study. However, we feel that this was not a large concern, because the study was adequately powered with the patients available to determine a difference based on subsidence.

CONCLUSION

We found no difference in subsidence, lucent lines >2 mm, posterior subluxation, and the Constant and DASH functional outcome scores when we compared TSA performed by a LTO with an ST technique with proximal collar press-fit humeral stem. These data cannot be extrapolated to metaphyseal fit stems, which may exhibit different settling characteristics in the setting of the LTO technique.

This paper will be judged for the Resident Writer’s Award.

ABSTRACT

Diaphyseal fractures of the distal humerus have a high rate of union when treated with a functional brace or an above-elbow cast (AEC). This study compares alignment of the humerus and motion of the elbow after functional brace or AEC treatment.

One-hundred and five consecutive patients with a closed, extra-articular fracture of the distal humeral diaphysis were identified in the orthopedic trauma databases of 3 hospitals between 2003 and 2012. Seventy-five patients with a follow-up of at least 6 months or with radiographic and clinical evidence of fracture union were included (51 treated with functional bracing and 24 treated with an AEC).

All of the fractures healed. The average arc of elbow flexion was 130° ± 9° in braced patients vs 127° ± 12° in casted patients. Four patients (8%) in the bracing group and 4 (17%) in the casting group lost >20° of elbow motion. The average varus angulation on radiographs was 17° ± 8° in braced and 13° ± 8° in casted patients, while the average posterior angulation was 9° ± 6° vs 7° ± 7°, respectively.

Closed extra-articular distal diaphyseal humerus fractures heal with both bracing and casting and there are no differences in average elbow motion or radiographic alignment.

Nonoperative treatment of closed fractures of the humeral shaft (AO/OTA [Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association] type 12) with a functional brace or above-elbow cast (AEC) is associated with a high union rate, good motion, and good function. Advocates of casting believe that a brace cannot control fracture alignment as well as a cast that allows for immobilization and molding. Advocates of brace treatment are concerned that immobilization in a cast will cause elbow stiffness.^1-11

Continue to: In our differing institutions...

MATERIALS AND METHODS

Between 2003 and 2012, consecutive adult patients treated for a nonpathological fracture of the diaphysis of the distal humerus at the orthopedic trauma service of 3 level 1 academic trauma centers were identified from prospectively collected trauma injury databases. Patients with vascular injury, ipsilateral upper extremity fracture, and periprosthetic fractures were excluded. The attending orthopedic surgeon chose the treatment method and evaluated the range of motion (ROM) of the elbow and radiographic union at the final ambulatory visit. We included patients followed to clinical and radiographic union with a minimum of 6 months of follow-up. We also included patients with <6 months’ follow-up who demonstrated union and had elbow ROM within 10° of the uninjured arm.

We identified 105 consecutive adult patients with a closed nonpathological extra-articular distal humeral shaft fracture (fracture of the distal humeral shaft with an AO/OTA type-12.A, 12.B, or 12.C pattern) treated with an AEC or a brace in our databases.¹² Two patients in the brace group chose surgery to improve alignment within 3 weeks of injury and were excluded from the analysis. Twenty-eight patients had inadequate follow-up.

A total of 75 patients were included in the study. At the first and second institutions, 51 patients were treated with functional bracing with an average follow-up of 7 months. At the third institution, 24 patients were treated with an AEC with an average follow-up of 4 months. Seventeen out of 24 patients in the long arm casting group and 19 out of 51 patients in the bracing group, who were included since they had <6 months of follow-up, demonstrated union and had elbow ROM within 10° of the uninjured arm. Differing methods of closed immobilization were the result of differing treatment algorithms at each institution.

The patients who were treated with a functional brace averaged 34 years of age (range, 18-90 years) and included 27 men and 24 women. The brace was removed at an average of 11.5 weeks (range, 8-18 weeks) after initial injury. Six patients had an injury-associated radial nerve palsy, all of which fully recovered within an average of 4 months (range, 0.5-7 months). Sixteen patients were injured due to a fall from standing height, 2 due to a fall from a greater height than standing, 16 in a motor-vehicle accident, 15 during a sport activity, and 2 were not specifically documented.

Continue to: Four patients had concomitant...

The patients who were treated with an AEC had an average age of 32 years (range,18-82 years) and included 14 men and 10 women. The cast was removed at an average of 4.2 weeks (range, 3-7 weeks) after the initial injury. Two patients had an injury-associated radial nerve palsy, both of which fully recovered. Five patients were injured due to a fall from standing height, 1 due to a fall from a height greater than standing, 7 during a motor-vehicle accident, 5 during a sport activity, and 6 were not documented. Two patients sustained concomitant injuries: one patient sustained a tibia-fibula fracture, and another patient sustained facial trauma.

The 2 groups were comparable in age and gender, as well as the injury mechanism (Table).

Table. Patient Demographics and Outcome Data

FUNCTIONAL BRACING TECHNIQUE

Upon presentation after injury, patients were immobilized in a coaptation splint (Figure 1A). Within 10 days, the arm was placed in a pre-manufactured polyethylene functional brace (Corflex) and the arm was supported with a simple sling. Patients were allowed to use the hand for light tasks and move the elbow, but most patients were not capable of active elbow flexion exercises until early healing was established 4 to 6 weeks after injury. Shoulder motion was discouraged until radiographic union. Patients started active, self-assisted elbow and shoulder stretching exercises, and weaned from the brace once radiographic union was confirmed between 6 and 10 weeks after injury (Figures 1B, 1C).

ABOVE-ELBOW CASE

Patients were also initially immobilized in a coaptation splint upon initial presentation. Within 7 days, an above-elbow fiberglass cast with neutral forearm rotation and 90° of elbow flexion was applied with a supracondylar mold, followed by radiographic imaging (Figure 2A). With the fractured arm dependent, a valgus mold was applied as the material hardened in order to align the fracture site and limit varus angulation.

Continue to: There were no shoulder...

STATISTICAL ANALYSIS

Alignment of the humerus (including varus-valgus alignment and apex anterior-posterior alignment) was measured on anteroposterior and lateral radiographs as the angle between lines bisecting the humeral diaphysis proximal and distal to the fracture. The normality of the data was tested using the Kolmogorov-Smirnov test. To statistically compare continuous variables with a normal distribution, t-tests were used; otherwise the Wilcoxon t-test was applied. The Pearson’s Chi-Square test was used to statistically compare dichotomous variables, except when expected cell frequency was <5, in which case the Fisher exact test was used. The level of significance was set at P < .05.

RESULTS

RANGE OF MOTION AND RADIOGRAPHIC ALIGNMENT

The average range of elbow motion was 130° ± 9° after brace treatment and 127° ± 12° after cast treatment (P = .26). Four patients (8%) treated with a brace and 3 (12%) treated with a cast lost >20° of elbow motion.

All the fractures healed. The average varus angulation on the anteroposterior radiograph was 17° (range, 2°-26°) in braced patients and 13 (range, 5°-31°) in casted patients (P = .11). The average posterior angulation on the lateral radiograph was 9° (range, 0°-28°) in braced patients vs 7° (range, 2°-33°) in casted patients (P = .54).

Continue to: Two weeks after initiating brace...

COMPLICATIONS

Two weeks after initiating brace treatment, an obese patient suffered a rash with desquamation that necessitated discontinuation of the brace. However, the skin and fracture ultimately healed with a coaptation splint and sling support without additional complications. In the casting cohort, 2 patients returned to the emergency department after AEC placement because of swelling of the hand and pain in the cast. Both casts were removed and reapplied.

DISCUSSION

Fractures of the distal third of the humeral diaphysis heal without surgery. Fracture angulation and elbow stiffness are the concerns that lead to variations in nonoperative treatment.^1-3 Advocates of casting believe they can get better alignment without losing elbow motion, and advocates of bracing feel that the brace is less cumbersome.^1-3,5-8 We compared these treatments retrospectively and found them comparable.

This study should be considered in light of its limitations. Many patients were lost to follow-up in our urban trauma centers. We do not know if these patients did better, worse, or the same as the patients we were able to evaluate, but our opinion is that patients having problems were more likely to return. The evaluation time was relatively short, but motion can only improve in the longer-term. Two patients that were initially braced chose surgery, probably because either they or their surgeon were nervous about the radiographic appearance of the fracture. In our opinion, continued nonoperative treatment of these patients would not affect the findings.

Cast treatment of distal diaphyseal humerus fractures does not cause permanent elbow stiffness. This is confirmed by our results; as casted patients did not lose final ROM compared to the bracing cohort. These injuries are extra-articular and casted patients are transitioned to bracing once humeri have significant union demonstrated by the arm moving as a unit. To our knowledge, there is no other study that has evaluated casting for these fractures, but it may be that evidence of permanent stiffness with nonoperative treatment of distal metaphyseal fractures of the humerus [AO/OTA type 13] is misapplied to distal humeral shaft fractures [AO/OTA type 12].^3,9,10,12 For brace treatment, Sarmiento and colleagues⁹ showed no significant elbow stiffness in a consecutive cohort of 69 patients, while Jawa and colleagues⁵ showed no increased elbow stiffness compared to plate fixation. Given the accumulated data,^3,5,6,8,13 advocates of operative treatment for distal third diaphyseal humerus fractures¹² can no longer site elbow stiffness as a disadvantage of nonoperative treatment, whether with cast or brace.

As shown in this study, patients that choose nonoperative treatment can expect their fracture to heal with an average of approximately 15° of varus angulation, as well as 2 others evaluating brace treatment.^5,9 Some will heal with as much as 30° of varus angulation.^5,9 The arm may look a little different, particularly in thin patients, but there is no evidence that this angulation affects function. The risks, discomforts, and inconveniences of surgery can be balanced with the ability of surgery to improve alignment and allow elbow motion a few weeks earlier. The aesthetics of the scar after surgery may not be better than the deformity after nonoperative treatment. Patients should be involved in these decisions.

Continue to: No cost comparison...

There is a passive implication that operative treatment of distal third diaphyseal humerus fractures affords better results and union for patients in the discussed literature. Our results demonstrate that the distal diaphyseal humerus has a natural anatomic and biologic propensity to heal with closed immobilization. Patients should be made aware that while operative treatments exist for this fracture pattern, nonoperative treatment modalities have proven to be efficacious using a variety of immobilization methods. Thus, patients that prefer nonoperative treatment of a distal third diaphyseal humerus fracture can choose between a cast or a brace with confidence of the efficacy of the nonoperative treatment.

ABSTRACT

Diaphyseal fractures of the distal humerus have a high rate of union when treated with a functional brace or an above-elbow cast (AEC). This study compares alignment of the humerus and motion of the elbow after functional brace or AEC treatment.

One-hundred and five consecutive patients with a closed, extra-articular fracture of the distal humeral diaphysis were identified in the orthopedic trauma databases of 3 hospitals between 2003 and 2012. Seventy-five patients with a follow-up of at least 6 months or with radiographic and clinical evidence of fracture union were included (51 treated with functional bracing and 24 treated with an AEC).

All of the fractures healed. The average arc of elbow flexion was 130° ± 9° in braced patients vs 127° ± 12° in casted patients. Four patients (8%) in the bracing group and 4 (17%) in the casting group lost >20° of elbow motion. The average varus angulation on radiographs was 17° ± 8° in braced and 13° ± 8° in casted patients, while the average posterior angulation was 9° ± 6° vs 7° ± 7°, respectively.

Closed extra-articular distal diaphyseal humerus fractures heal with both bracing and casting and there are no differences in average elbow motion or radiographic alignment.

Nonoperative treatment of closed fractures of the humeral shaft (AO/OTA [Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association] type 12) with a functional brace or above-elbow cast (AEC) is associated with a high union rate, good motion, and good function. Advocates of casting believe that a brace cannot control fracture alignment as well as a cast that allows for immobilization and molding. Advocates of brace treatment are concerned that immobilization in a cast will cause elbow stiffness.^1-11

Continue to: In our differing institutions...

MATERIALS AND METHODS

Between 2003 and 2012, consecutive adult patients treated for a nonpathological fracture of the diaphysis of the distal humerus at the orthopedic trauma service of 3 level 1 academic trauma centers were identified from prospectively collected trauma injury databases. Patients with vascular injury, ipsilateral upper extremity fracture, and periprosthetic fractures were excluded. The attending orthopedic surgeon chose the treatment method and evaluated the range of motion (ROM) of the elbow and radiographic union at the final ambulatory visit. We included patients followed to clinical and radiographic union with a minimum of 6 months of follow-up. We also included patients with <6 months’ follow-up who demonstrated union and had elbow ROM within 10° of the uninjured arm.

We identified 105 consecutive adult patients with a closed nonpathological extra-articular distal humeral shaft fracture (fracture of the distal humeral shaft with an AO/OTA type-12.A, 12.B, or 12.C pattern) treated with an AEC or a brace in our databases.¹² Two patients in the brace group chose surgery to improve alignment within 3 weeks of injury and were excluded from the analysis. Twenty-eight patients had inadequate follow-up.

A total of 75 patients were included in the study. At the first and second institutions, 51 patients were treated with functional bracing with an average follow-up of 7 months. At the third institution, 24 patients were treated with an AEC with an average follow-up of 4 months. Seventeen out of 24 patients in the long arm casting group and 19 out of 51 patients in the bracing group, who were included since they had <6 months of follow-up, demonstrated union and had elbow ROM within 10° of the uninjured arm. Differing methods of closed immobilization were the result of differing treatment algorithms at each institution.

The patients who were treated with a functional brace averaged 34 years of age (range, 18-90 years) and included 27 men and 24 women. The brace was removed at an average of 11.5 weeks (range, 8-18 weeks) after initial injury. Six patients had an injury-associated radial nerve palsy, all of which fully recovered within an average of 4 months (range, 0.5-7 months). Sixteen patients were injured due to a fall from standing height, 2 due to a fall from a greater height than standing, 16 in a motor-vehicle accident, 15 during a sport activity, and 2 were not specifically documented.

Continue to: Four patients had concomitant...

The patients who were treated with an AEC had an average age of 32 years (range,18-82 years) and included 14 men and 10 women. The cast was removed at an average of 4.2 weeks (range, 3-7 weeks) after the initial injury. Two patients had an injury-associated radial nerve palsy, both of which fully recovered. Five patients were injured due to a fall from standing height, 1 due to a fall from a height greater than standing, 7 during a motor-vehicle accident, 5 during a sport activity, and 6 were not documented. Two patients sustained concomitant injuries: one patient sustained a tibia-fibula fracture, and another patient sustained facial trauma.

The 2 groups were comparable in age and gender, as well as the injury mechanism (Table).

Table. Patient Demographics and Outcome Data

FUNCTIONAL BRACING TECHNIQUE

Upon presentation after injury, patients were immobilized in a coaptation splint (Figure 1A). Within 10 days, the arm was placed in a pre-manufactured polyethylene functional brace (Corflex) and the arm was supported with a simple sling. Patients were allowed to use the hand for light tasks and move the elbow, but most patients were not capable of active elbow flexion exercises until early healing was established 4 to 6 weeks after injury. Shoulder motion was discouraged until radiographic union. Patients started active, self-assisted elbow and shoulder stretching exercises, and weaned from the brace once radiographic union was confirmed between 6 and 10 weeks after injury (Figures 1B, 1C).

ABOVE-ELBOW CASE

Patients were also initially immobilized in a coaptation splint upon initial presentation. Within 7 days, an above-elbow fiberglass cast with neutral forearm rotation and 90° of elbow flexion was applied with a supracondylar mold, followed by radiographic imaging (Figure 2A). With the fractured arm dependent, a valgus mold was applied as the material hardened in order to align the fracture site and limit varus angulation.

Continue to: There were no shoulder...

STATISTICAL ANALYSIS

Alignment of the humerus (including varus-valgus alignment and apex anterior-posterior alignment) was measured on anteroposterior and lateral radiographs as the angle between lines bisecting the humeral diaphysis proximal and distal to the fracture. The normality of the data was tested using the Kolmogorov-Smirnov test. To statistically compare continuous variables with a normal distribution, t-tests were used; otherwise the Wilcoxon t-test was applied. The Pearson’s Chi-Square test was used to statistically compare dichotomous variables, except when expected cell frequency was <5, in which case the Fisher exact test was used. The level of significance was set at P < .05.

RESULTS

RANGE OF MOTION AND RADIOGRAPHIC ALIGNMENT

The average range of elbow motion was 130° ± 9° after brace treatment and 127° ± 12° after cast treatment (P = .26). Four patients (8%) treated with a brace and 3 (12%) treated with a cast lost >20° of elbow motion.

All the fractures healed. The average varus angulation on the anteroposterior radiograph was 17° (range, 2°-26°) in braced patients and 13 (range, 5°-31°) in casted patients (P = .11). The average posterior angulation on the lateral radiograph was 9° (range, 0°-28°) in braced patients vs 7° (range, 2°-33°) in casted patients (P = .54).

Continue to: Two weeks after initiating brace...

COMPLICATIONS

Two weeks after initiating brace treatment, an obese patient suffered a rash with desquamation that necessitated discontinuation of the brace. However, the skin and fracture ultimately healed with a coaptation splint and sling support without additional complications. In the casting cohort, 2 patients returned to the emergency department after AEC placement because of swelling of the hand and pain in the cast. Both casts were removed and reapplied.

DISCUSSION

Fractures of the distal third of the humeral diaphysis heal without surgery. Fracture angulation and elbow stiffness are the concerns that lead to variations in nonoperative treatment.^1-3 Advocates of casting believe they can get better alignment without losing elbow motion, and advocates of bracing feel that the brace is less cumbersome.^1-3,5-8 We compared these treatments retrospectively and found them comparable.

This study should be considered in light of its limitations. Many patients were lost to follow-up in our urban trauma centers. We do not know if these patients did better, worse, or the same as the patients we were able to evaluate, but our opinion is that patients having problems were more likely to return. The evaluation time was relatively short, but motion can only improve in the longer-term. Two patients that were initially braced chose surgery, probably because either they or their surgeon were nervous about the radiographic appearance of the fracture. In our opinion, continued nonoperative treatment of these patients would not affect the findings.

Cast treatment of distal diaphyseal humerus fractures does not cause permanent elbow stiffness. This is confirmed by our results; as casted patients did not lose final ROM compared to the bracing cohort. These injuries are extra-articular and casted patients are transitioned to bracing once humeri have significant union demonstrated by the arm moving as a unit. To our knowledge, there is no other study that has evaluated casting for these fractures, but it may be that evidence of permanent stiffness with nonoperative treatment of distal metaphyseal fractures of the humerus [AO/OTA type 13] is misapplied to distal humeral shaft fractures [AO/OTA type 12].^3,9,10,12 For brace treatment, Sarmiento and colleagues⁹ showed no significant elbow stiffness in a consecutive cohort of 69 patients, while Jawa and colleagues⁵ showed no increased elbow stiffness compared to plate fixation. Given the accumulated data,^3,5,6,8,13 advocates of operative treatment for distal third diaphyseal humerus fractures¹² can no longer site elbow stiffness as a disadvantage of nonoperative treatment, whether with cast or brace.

As shown in this study, patients that choose nonoperative treatment can expect their fracture to heal with an average of approximately 15° of varus angulation, as well as 2 others evaluating brace treatment.^5,9 Some will heal with as much as 30° of varus angulation.^5,9 The arm may look a little different, particularly in thin patients, but there is no evidence that this angulation affects function. The risks, discomforts, and inconveniences of surgery can be balanced with the ability of surgery to improve alignment and allow elbow motion a few weeks earlier. The aesthetics of the scar after surgery may not be better than the deformity after nonoperative treatment. Patients should be involved in these decisions.

Continue to: No cost comparison...

There is a passive implication that operative treatment of distal third diaphyseal humerus fractures affords better results and union for patients in the discussed literature. Our results demonstrate that the distal diaphyseal humerus has a natural anatomic and biologic propensity to heal with closed immobilization. Patients should be made aware that while operative treatments exist for this fracture pattern, nonoperative treatment modalities have proven to be efficacious using a variety of immobilization methods. Thus, patients that prefer nonoperative treatment of a distal third diaphyseal humerus fracture can choose between a cast or a brace with confidence of the efficacy of the nonoperative treatment.

ABSTRACT

Diaphyseal fractures of the distal humerus have a high rate of union when treated with a functional brace or an above-elbow cast (AEC). This study compares alignment of the humerus and motion of the elbow after functional brace or AEC treatment.

One-hundred and five consecutive patients with a closed, extra-articular fracture of the distal humeral diaphysis were identified in the orthopedic trauma databases of 3 hospitals between 2003 and 2012. Seventy-five patients with a follow-up of at least 6 months or with radiographic and clinical evidence of fracture union were included (51 treated with functional bracing and 24 treated with an AEC).

All of the fractures healed. The average arc of elbow flexion was 130° ± 9° in braced patients vs 127° ± 12° in casted patients. Four patients (8%) in the bracing group and 4 (17%) in the casting group lost >20° of elbow motion. The average varus angulation on radiographs was 17° ± 8° in braced and 13° ± 8° in casted patients, while the average posterior angulation was 9° ± 6° vs 7° ± 7°, respectively.

Closed extra-articular distal diaphyseal humerus fractures heal with both bracing and casting and there are no differences in average elbow motion or radiographic alignment.

Nonoperative treatment of closed fractures of the humeral shaft (AO/OTA [Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association] type 12) with a functional brace or above-elbow cast (AEC) is associated with a high union rate, good motion, and good function. Advocates of casting believe that a brace cannot control fracture alignment as well as a cast that allows for immobilization and molding. Advocates of brace treatment are concerned that immobilization in a cast will cause elbow stiffness.^1-11

Continue to: In our differing institutions...

MATERIALS AND METHODS

Between 2003 and 2012, consecutive adult patients treated for a nonpathological fracture of the diaphysis of the distal humerus at the orthopedic trauma service of 3 level 1 academic trauma centers were identified from prospectively collected trauma injury databases. Patients with vascular injury, ipsilateral upper extremity fracture, and periprosthetic fractures were excluded. The attending orthopedic surgeon chose the treatment method and evaluated the range of motion (ROM) of the elbow and radiographic union at the final ambulatory visit. We included patients followed to clinical and radiographic union with a minimum of 6 months of follow-up. We also included patients with <6 months’ follow-up who demonstrated union and had elbow ROM within 10° of the uninjured arm.

We identified 105 consecutive adult patients with a closed nonpathological extra-articular distal humeral shaft fracture (fracture of the distal humeral shaft with an AO/OTA type-12.A, 12.B, or 12.C pattern) treated with an AEC or a brace in our databases.¹² Two patients in the brace group chose surgery to improve alignment within 3 weeks of injury and were excluded from the analysis. Twenty-eight patients had inadequate follow-up.

A total of 75 patients were included in the study. At the first and second institutions, 51 patients were treated with functional bracing with an average follow-up of 7 months. At the third institution, 24 patients were treated with an AEC with an average follow-up of 4 months. Seventeen out of 24 patients in the long arm casting group and 19 out of 51 patients in the bracing group, who were included since they had <6 months of follow-up, demonstrated union and had elbow ROM within 10° of the uninjured arm. Differing methods of closed immobilization were the result of differing treatment algorithms at each institution.

The patients who were treated with a functional brace averaged 34 years of age (range, 18-90 years) and included 27 men and 24 women. The brace was removed at an average of 11.5 weeks (range, 8-18 weeks) after initial injury. Six patients had an injury-associated radial nerve palsy, all of which fully recovered within an average of 4 months (range, 0.5-7 months). Sixteen patients were injured due to a fall from standing height, 2 due to a fall from a greater height than standing, 16 in a motor-vehicle accident, 15 during a sport activity, and 2 were not specifically documented.

Continue to: Four patients had concomitant...

The patients who were treated with an AEC had an average age of 32 years (range,18-82 years) and included 14 men and 10 women. The cast was removed at an average of 4.2 weeks (range, 3-7 weeks) after the initial injury. Two patients had an injury-associated radial nerve palsy, both of which fully recovered. Five patients were injured due to a fall from standing height, 1 due to a fall from a height greater than standing, 7 during a motor-vehicle accident, 5 during a sport activity, and 6 were not documented. Two patients sustained concomitant injuries: one patient sustained a tibia-fibula fracture, and another patient sustained facial trauma.

The 2 groups were comparable in age and gender, as well as the injury mechanism (Table).

Table. Patient Demographics and Outcome Data

FUNCTIONAL BRACING TECHNIQUE

Upon presentation after injury, patients were immobilized in a coaptation splint (Figure 1A). Within 10 days, the arm was placed in a pre-manufactured polyethylene functional brace (Corflex) and the arm was supported with a simple sling. Patients were allowed to use the hand for light tasks and move the elbow, but most patients were not capable of active elbow flexion exercises until early healing was established 4 to 6 weeks after injury. Shoulder motion was discouraged until radiographic union. Patients started active, self-assisted elbow and shoulder stretching exercises, and weaned from the brace once radiographic union was confirmed between 6 and 10 weeks after injury (Figures 1B, 1C).

ABOVE-ELBOW CASE

Patients were also initially immobilized in a coaptation splint upon initial presentation. Within 7 days, an above-elbow fiberglass cast with neutral forearm rotation and 90° of elbow flexion was applied with a supracondylar mold, followed by radiographic imaging (Figure 2A). With the fractured arm dependent, a valgus mold was applied as the material hardened in order to align the fracture site and limit varus angulation.

Continue to: There were no shoulder...

STATISTICAL ANALYSIS

Alignment of the humerus (including varus-valgus alignment and apex anterior-posterior alignment) was measured on anteroposterior and lateral radiographs as the angle between lines bisecting the humeral diaphysis proximal and distal to the fracture. The normality of the data was tested using the Kolmogorov-Smirnov test. To statistically compare continuous variables with a normal distribution, t-tests were used; otherwise the Wilcoxon t-test was applied. The Pearson’s Chi-Square test was used to statistically compare dichotomous variables, except when expected cell frequency was <5, in which case the Fisher exact test was used. The level of significance was set at P < .05.

RESULTS

RANGE OF MOTION AND RADIOGRAPHIC ALIGNMENT

The average range of elbow motion was 130° ± 9° after brace treatment and 127° ± 12° after cast treatment (P = .26). Four patients (8%) treated with a brace and 3 (12%) treated with a cast lost >20° of elbow motion.

All the fractures healed. The average varus angulation on the anteroposterior radiograph was 17° (range, 2°-26°) in braced patients and 13 (range, 5°-31°) in casted patients (P = .11). The average posterior angulation on the lateral radiograph was 9° (range, 0°-28°) in braced patients vs 7° (range, 2°-33°) in casted patients (P = .54).

Continue to: Two weeks after initiating brace...

COMPLICATIONS

Two weeks after initiating brace treatment, an obese patient suffered a rash with desquamation that necessitated discontinuation of the brace. However, the skin and fracture ultimately healed with a coaptation splint and sling support without additional complications. In the casting cohort, 2 patients returned to the emergency department after AEC placement because of swelling of the hand and pain in the cast. Both casts were removed and reapplied.

DISCUSSION

Fractures of the distal third of the humeral diaphysis heal without surgery. Fracture angulation and elbow stiffness are the concerns that lead to variations in nonoperative treatment.^1-3 Advocates of casting believe they can get better alignment without losing elbow motion, and advocates of bracing feel that the brace is less cumbersome.^1-3,5-8 We compared these treatments retrospectively and found them comparable.

This study should be considered in light of its limitations. Many patients were lost to follow-up in our urban trauma centers. We do not know if these patients did better, worse, or the same as the patients we were able to evaluate, but our opinion is that patients having problems were more likely to return. The evaluation time was relatively short, but motion can only improve in the longer-term. Two patients that were initially braced chose surgery, probably because either they or their surgeon were nervous about the radiographic appearance of the fracture. In our opinion, continued nonoperative treatment of these patients would not affect the findings.

Cast treatment of distal diaphyseal humerus fractures does not cause permanent elbow stiffness. This is confirmed by our results; as casted patients did not lose final ROM compared to the bracing cohort. These injuries are extra-articular and casted patients are transitioned to bracing once humeri have significant union demonstrated by the arm moving as a unit. To our knowledge, there is no other study that has evaluated casting for these fractures, but it may be that evidence of permanent stiffness with nonoperative treatment of distal metaphyseal fractures of the humerus [AO/OTA type 13] is misapplied to distal humeral shaft fractures [AO/OTA type 12].^3,9,10,12 For brace treatment, Sarmiento and colleagues⁹ showed no significant elbow stiffness in a consecutive cohort of 69 patients, while Jawa and colleagues⁵ showed no increased elbow stiffness compared to plate fixation. Given the accumulated data,^3,5,6,8,13 advocates of operative treatment for distal third diaphyseal humerus fractures¹² can no longer site elbow stiffness as a disadvantage of nonoperative treatment, whether with cast or brace.

As shown in this study, patients that choose nonoperative treatment can expect their fracture to heal with an average of approximately 15° of varus angulation, as well as 2 others evaluating brace treatment.^5,9 Some will heal with as much as 30° of varus angulation.^5,9 The arm may look a little different, particularly in thin patients, but there is no evidence that this angulation affects function. The risks, discomforts, and inconveniences of surgery can be balanced with the ability of surgery to improve alignment and allow elbow motion a few weeks earlier. The aesthetics of the scar after surgery may not be better than the deformity after nonoperative treatment. Patients should be involved in these decisions.

Continue to: No cost comparison...

There is a passive implication that operative treatment of distal third diaphyseal humerus fractures affords better results and union for patients in the discussed literature. Our results demonstrate that the distal diaphyseal humerus has a natural anatomic and biologic propensity to heal with closed immobilization. Patients should be made aware that while operative treatments exist for this fracture pattern, nonoperative treatment modalities have proven to be efficacious using a variety of immobilization methods. Thus, patients that prefer nonoperative treatment of a distal third diaphyseal humerus fracture can choose between a cast or a brace with confidence of the efficacy of the nonoperative treatment.

ABSTRACT

The objective of this study is to determine the reproducibility and feasibility of using 3-dimensional (3-D) computer simulation of proximal humerus fracture computed tomography (CT) scans for fracture reduction. We hypothesized that anatomic reconstruction with 3-D models would be anatomically accurate and reproducible.

Preoperative CT scans of 28 patients with 3- and 4-part (AO classification 11-B1, 11-B2, 11-C1, 11-C2) proximal humerus fractures who were treated by hemiarthroplasty were converted into 3-D computer models. The displaced fractured fragments were anatomically reduced with computer simulation by 2 fellowship-trained shoulder surgeons, and measurements were made of the reconstructed proximal humerus.

The measurements of the reconstructed models had very good to excellent interobserver and intraobserver reliability. The reconstructions of these humerus fractures showed interclass correlation coefficients ranging from 0.71 to 0.93 between 1 observer and from 0.82 to 0.98 between 2 different observers. The fracture reduction was judged against normal proximal humerus geometry to determine reduction accuracy.

The 3-D modeling techniques used to reconstruct 3- and 4-part proximal humerus fractures were reliable and accurate. This technique of modeling and reconstructing proximal humerus fractures could be used to enhance the preoperative planning of open reduction and internal fixation or hemiarthroplasty for 3- and 4-part proximal humerus fractures.

The treatment of proximal humerus fractures is influenced by multiple factors, including patient age, associated injuries, bone quality, and fracture pattern. Three- and 4-part fractures are among the more severe of these fractures, which may result in vascular compromise to the humeral head, leading to avascular necrosis. Surgical goals for the management of these fractures are to optimize functional outcomes by re-creating a stable construct with a functional rotator cuff by open reduction and internal fixation (ORIF), hemiarthroplasty with tuberosity ORIF, or reverse shoulder replacement. Achieving a good outcome following hemiarthroplasty is dependent on many factors, including anatomic tuberosity healing and component positioning.^1,2,3 Repairing the greater tuberosity in a near-anatomic position has been shown to greatly affect the results of hemiarthroplasty for fracture.^3,4

Continue to: Three-dimensional (3-D) modeling...

METHODS

After Institutional Review Board approval was obtained, we reviewed the medical records of consecutive patients with a diagnosis of proximal humeral fracture and the treatment codes for hemiarthroplasty from 2000 to 2013. Inclusion criteria included 3- and 4-part fractures (AO classifications 11-B1, 11-B2, 11-C1, 11-C2). CT scans with insufficient quality to differentiate bone from soft tissue (inadequate signal-to-noise ratio) were excluded from the study. A total of 28 patients with adequate CT scans met the criteria for inclusion in this study.

The CT scan protocol included 0.5-mm axial cuts with inclusion of the proximal humerus in the Digital Imaging and Communications in Medicine format. These CT scans were converted into patient-specific 3-D computer models of the shoulder using Mimics software (Materialise Inc.). The use of this software to produce anatomically accurate models has previously been verified in a shoulder model.^6,7 The tuberosity fragments were then individually separated from each other using the voxel-selecting capabilities of 3-D software and manipulated with translation and rotation for anatomic reduction (Figures 1A-1D, Figure 2).

The de-identified anatomically reconstructed shoulder models were then uploaded into Materialise’s Magics rapid prototyping software, and a user-defined humeral Cartesian coordinate system was defined with anatomic landmarks as reference points to standardize the position of each model (Figure 3).^8,9 

A series of measurements were made on these models to assess the validity and reliability of the reassembly. The bicipital groove at the anatomic neck was used to measure humeral head version as described by Kummer and colleagues.¹⁰ The head-shaft angle, humeral head-greater tuberosity distance, humeral head-bicipital groove angle, and posterior and medial humeral head offset were measured directly on the reconstructed humerus.

Continue to: Two fellowship-trained shoulder...

STATISTICS

The measured dimensions of the 28 reassembled proximal humeri models were averaged across all trials between the 2 fellowship-trained surgeons and compared with the range of normal dimensions of a healthy proximal humerus using the 2 one-sided tests (TOST) method for equivalence between 2 means given a range. The interobserver and intraobserver reliabilities were quantified using the interclass correlation coefficient. An excellent correlation was defined as a correlation coefficient >0.81; very good was defined as 0.61 to 0.80; and good was defined as 0.41 to 0.60.

RESULTS

Of the patients studied, 9 (32.1%) were male, and the average age at the time of CT scanning was 72 years. Of the 28 patients with fracture, 18 (64.2%) had 3-part fractures (AO classifications 11-B1, 11-B2), and 10 (35.8%) had 4-part fractures (AO classifications 11-C1, 11-C2). When examining the location of the intertubercular fracture line, we found that 13 (46.4%) fractures went through the bicipital groove. Of the remaining fracture lines, 9 (32.1%) extended into the greater tuberosity and 6 (21.4%) extended into the lesser tuberosity.

All users were able to reconstruct all 28 fractures using this technique. The average measured dimensions fell within the range of dimensions of a normal healthy proximal humerus specified in the literature to within a 95% confidence interval using the TOST for equivalence, in which we compared measured values with ranges reported in the literature (Table).^11,12,13 

Table. Dimensions of Proximal Humerus Geometry

The reconstructions of these humerus fractures showed intraclass correlation coefficients ranging from 0.71 to 0.93 in 1 observer and interclass correlation coefficients from 0.82 to 0.98 between 2 different observers (Table).

DISCUSSION

This study demonstrates that it is feasible to reliably and accurately reconstruct the original anatomy of the proximal humerus by using 3-D computer modeling of proximal humerus fractures. Poor outcomes after hemiarthroplasty for proximal humerus fractures are mostly related to tuberosity malpositioning, resorption, or failure of fixation and resultant dysfunction of the rotator cuff.^14,15,16 These studies highlight the importance of accurate tuberosity reduction during surgical care of these fractures.

Continue to: The 3-D computer model...

Overreduction of greater tuberosity to create cortical overlap with the lateral shaft may be used to promote bony union. As a result of this distalization, there may be extra strains placed on the rotator cuff, making the patient more prone to rotator cuff tear, as well as improperly balancing the dynamic stabilizers of the shoulder. Poor clinical outcomes in hemiarthroplasty for proximal humerus fractures have been correlated with a greater tuberosity placed distal relative to the humeral head by 1 cm in a study² and by 2 cm in another.³

This study has several limitations. The first is the assumption that our injured patients had preinjury proximal humerus geometry within the range of normal dimensions of a healthy humerus. Unfortunately, because we were unable to obtain CT scans of the contralateral shoulder, we had to use standard proximal humerus geometry as the control. Another limitation, inherent in the technique, is that only cortical and dense trabecular bone was modeled, so that comminuted or osteoporotic bone was not well modeled. This study did not correlate the findings from these models with clinical outcomes. A prospective study is needed to evaluate the impact of this 3-D modeling on fracture reductions and clinical outcomes.

This study demonstrates that patient-specific modeling of proximal humerus fracture 3-D CT scans may help surgeons reliably and accurately reconstruct fractures. This technique may have utility in the preoperative planning of tuberosity fracture reduction and hemiarthroplasty. It gives surgeons the ability to visualize fracture fragments, and the process of reconstructing the fragments may help surgeons understand the required maneuvers for reduction at the time of surgery. This technique also provides dimensions of the patient’s native humerus, thus potentially improving the anatomic accuracy of the reduction or hemiarthroplasty reconstruction. With the new trend toward patient-specific instrumentation, this study also provides a means of planning the size of the humeral prostheses as well as the version relative to the biceps groove and intertubercular fracture line.

CONCLUSION

This study demonstrates the feasibility of using 3-D computer modeling of complex proximal humerus fractures in anatomic reconstruction. These techniques of computer-simulated 3-D models are valid and reliable. We believe that this technique of modeling and reconstructing proximal humerus fractures could be used to enhance the preoperative planning of hemiarthroplasty for 3- and 4-part proximal humerus fractures by providing improved understanding of the patient’s native humeral geometry and tuberosity reduction.

ABSTRACT

The objective of this study is to determine the reproducibility and feasibility of using 3-dimensional (3-D) computer simulation of proximal humerus fracture computed tomography (CT) scans for fracture reduction. We hypothesized that anatomic reconstruction with 3-D models would be anatomically accurate and reproducible.

Preoperative CT scans of 28 patients with 3- and 4-part (AO classification 11-B1, 11-B2, 11-C1, 11-C2) proximal humerus fractures who were treated by hemiarthroplasty were converted into 3-D computer models. The displaced fractured fragments were anatomically reduced with computer simulation by 2 fellowship-trained shoulder surgeons, and measurements were made of the reconstructed proximal humerus.

The measurements of the reconstructed models had very good to excellent interobserver and intraobserver reliability. The reconstructions of these humerus fractures showed interclass correlation coefficients ranging from 0.71 to 0.93 between 1 observer and from 0.82 to 0.98 between 2 different observers. The fracture reduction was judged against normal proximal humerus geometry to determine reduction accuracy.

The 3-D modeling techniques used to reconstruct 3- and 4-part proximal humerus fractures were reliable and accurate. This technique of modeling and reconstructing proximal humerus fractures could be used to enhance the preoperative planning of open reduction and internal fixation or hemiarthroplasty for 3- and 4-part proximal humerus fractures.

The treatment of proximal humerus fractures is influenced by multiple factors, including patient age, associated injuries, bone quality, and fracture pattern. Three- and 4-part fractures are among the more severe of these fractures, which may result in vascular compromise to the humeral head, leading to avascular necrosis. Surgical goals for the management of these fractures are to optimize functional outcomes by re-creating a stable construct with a functional rotator cuff by open reduction and internal fixation (ORIF), hemiarthroplasty with tuberosity ORIF, or reverse shoulder replacement. Achieving a good outcome following hemiarthroplasty is dependent on many factors, including anatomic tuberosity healing and component positioning.^1,2,3 Repairing the greater tuberosity in a near-anatomic position has been shown to greatly affect the results of hemiarthroplasty for fracture.^3,4

Continue to: Three-dimensional (3-D) modeling...

METHODS

After Institutional Review Board approval was obtained, we reviewed the medical records of consecutive patients with a diagnosis of proximal humeral fracture and the treatment codes for hemiarthroplasty from 2000 to 2013. Inclusion criteria included 3- and 4-part fractures (AO classifications 11-B1, 11-B2, 11-C1, 11-C2). CT scans with insufficient quality to differentiate bone from soft tissue (inadequate signal-to-noise ratio) were excluded from the study. A total of 28 patients with adequate CT scans met the criteria for inclusion in this study.

The CT scan protocol included 0.5-mm axial cuts with inclusion of the proximal humerus in the Digital Imaging and Communications in Medicine format. These CT scans were converted into patient-specific 3-D computer models of the shoulder using Mimics software (Materialise Inc.). The use of this software to produce anatomically accurate models has previously been verified in a shoulder model.^6,7 The tuberosity fragments were then individually separated from each other using the voxel-selecting capabilities of 3-D software and manipulated with translation and rotation for anatomic reduction (Figures 1A-1D, Figure 2).

The de-identified anatomically reconstructed shoulder models were then uploaded into Materialise’s Magics rapid prototyping software, and a user-defined humeral Cartesian coordinate system was defined with anatomic landmarks as reference points to standardize the position of each model (Figure 3).^8,9 

A series of measurements were made on these models to assess the validity and reliability of the reassembly. The bicipital groove at the anatomic neck was used to measure humeral head version as described by Kummer and colleagues.¹⁰ The head-shaft angle, humeral head-greater tuberosity distance, humeral head-bicipital groove angle, and posterior and medial humeral head offset were measured directly on the reconstructed humerus.

Continue to: Two fellowship-trained shoulder...

STATISTICS

The measured dimensions of the 28 reassembled proximal humeri models were averaged across all trials between the 2 fellowship-trained surgeons and compared with the range of normal dimensions of a healthy proximal humerus using the 2 one-sided tests (TOST) method for equivalence between 2 means given a range. The interobserver and intraobserver reliabilities were quantified using the interclass correlation coefficient. An excellent correlation was defined as a correlation coefficient >0.81; very good was defined as 0.61 to 0.80; and good was defined as 0.41 to 0.60.

RESULTS

Of the patients studied, 9 (32.1%) were male, and the average age at the time of CT scanning was 72 years. Of the 28 patients with fracture, 18 (64.2%) had 3-part fractures (AO classifications 11-B1, 11-B2), and 10 (35.8%) had 4-part fractures (AO classifications 11-C1, 11-C2). When examining the location of the intertubercular fracture line, we found that 13 (46.4%) fractures went through the bicipital groove. Of the remaining fracture lines, 9 (32.1%) extended into the greater tuberosity and 6 (21.4%) extended into the lesser tuberosity.

All users were able to reconstruct all 28 fractures using this technique. The average measured dimensions fell within the range of dimensions of a normal healthy proximal humerus specified in the literature to within a 95% confidence interval using the TOST for equivalence, in which we compared measured values with ranges reported in the literature (Table).^11,12,13 

Table. Dimensions of Proximal Humerus Geometry

The reconstructions of these humerus fractures showed intraclass correlation coefficients ranging from 0.71 to 0.93 in 1 observer and interclass correlation coefficients from 0.82 to 0.98 between 2 different observers (Table).

DISCUSSION

This study demonstrates that it is feasible to reliably and accurately reconstruct the original anatomy of the proximal humerus by using 3-D computer modeling of proximal humerus fractures. Poor outcomes after hemiarthroplasty for proximal humerus fractures are mostly related to tuberosity malpositioning, resorption, or failure of fixation and resultant dysfunction of the rotator cuff.^14,15,16 These studies highlight the importance of accurate tuberosity reduction during surgical care of these fractures.

Continue to: The 3-D computer model...

Overreduction of greater tuberosity to create cortical overlap with the lateral shaft may be used to promote bony union. As a result of this distalization, there may be extra strains placed on the rotator cuff, making the patient more prone to rotator cuff tear, as well as improperly balancing the dynamic stabilizers of the shoulder. Poor clinical outcomes in hemiarthroplasty for proximal humerus fractures have been correlated with a greater tuberosity placed distal relative to the humeral head by 1 cm in a study² and by 2 cm in another.³

This study has several limitations. The first is the assumption that our injured patients had preinjury proximal humerus geometry within the range of normal dimensions of a healthy humerus. Unfortunately, because we were unable to obtain CT scans of the contralateral shoulder, we had to use standard proximal humerus geometry as the control. Another limitation, inherent in the technique, is that only cortical and dense trabecular bone was modeled, so that comminuted or osteoporotic bone was not well modeled. This study did not correlate the findings from these models with clinical outcomes. A prospective study is needed to evaluate the impact of this 3-D modeling on fracture reductions and clinical outcomes.

This study demonstrates that patient-specific modeling of proximal humerus fracture 3-D CT scans may help surgeons reliably and accurately reconstruct fractures. This technique may have utility in the preoperative planning of tuberosity fracture reduction and hemiarthroplasty. It gives surgeons the ability to visualize fracture fragments, and the process of reconstructing the fragments may help surgeons understand the required maneuvers for reduction at the time of surgery. This technique also provides dimensions of the patient’s native humerus, thus potentially improving the anatomic accuracy of the reduction or hemiarthroplasty reconstruction. With the new trend toward patient-specific instrumentation, this study also provides a means of planning the size of the humeral prostheses as well as the version relative to the biceps groove and intertubercular fracture line.

CONCLUSION

This study demonstrates the feasibility of using 3-D computer modeling of complex proximal humerus fractures in anatomic reconstruction. These techniques of computer-simulated 3-D models are valid and reliable. We believe that this technique of modeling and reconstructing proximal humerus fractures could be used to enhance the preoperative planning of hemiarthroplasty for 3- and 4-part proximal humerus fractures by providing improved understanding of the patient’s native humeral geometry and tuberosity reduction.

ABSTRACT

The objective of this study is to determine the reproducibility and feasibility of using 3-dimensional (3-D) computer simulation of proximal humerus fracture computed tomography (CT) scans for fracture reduction. We hypothesized that anatomic reconstruction with 3-D models would be anatomically accurate and reproducible.

Preoperative CT scans of 28 patients with 3- and 4-part (AO classification 11-B1, 11-B2, 11-C1, 11-C2) proximal humerus fractures who were treated by hemiarthroplasty were converted into 3-D computer models. The displaced fractured fragments were anatomically reduced with computer simulation by 2 fellowship-trained shoulder surgeons, and measurements were made of the reconstructed proximal humerus.

The measurements of the reconstructed models had very good to excellent interobserver and intraobserver reliability. The reconstructions of these humerus fractures showed interclass correlation coefficients ranging from 0.71 to 0.93 between 1 observer and from 0.82 to 0.98 between 2 different observers. The fracture reduction was judged against normal proximal humerus geometry to determine reduction accuracy.

The 3-D modeling techniques used to reconstruct 3- and 4-part proximal humerus fractures were reliable and accurate. This technique of modeling and reconstructing proximal humerus fractures could be used to enhance the preoperative planning of open reduction and internal fixation or hemiarthroplasty for 3- and 4-part proximal humerus fractures.

The treatment of proximal humerus fractures is influenced by multiple factors, including patient age, associated injuries, bone quality, and fracture pattern. Three- and 4-part fractures are among the more severe of these fractures, which may result in vascular compromise to the humeral head, leading to avascular necrosis. Surgical goals for the management of these fractures are to optimize functional outcomes by re-creating a stable construct with a functional rotator cuff by open reduction and internal fixation (ORIF), hemiarthroplasty with tuberosity ORIF, or reverse shoulder replacement. Achieving a good outcome following hemiarthroplasty is dependent on many factors, including anatomic tuberosity healing and component positioning.^1,2,3 Repairing the greater tuberosity in a near-anatomic position has been shown to greatly affect the results of hemiarthroplasty for fracture.^3,4

Continue to: Three-dimensional (3-D) modeling...

METHODS

After Institutional Review Board approval was obtained, we reviewed the medical records of consecutive patients with a diagnosis of proximal humeral fracture and the treatment codes for hemiarthroplasty from 2000 to 2013. Inclusion criteria included 3- and 4-part fractures (AO classifications 11-B1, 11-B2, 11-C1, 11-C2). CT scans with insufficient quality to differentiate bone from soft tissue (inadequate signal-to-noise ratio) were excluded from the study. A total of 28 patients with adequate CT scans met the criteria for inclusion in this study.

The CT scan protocol included 0.5-mm axial cuts with inclusion of the proximal humerus in the Digital Imaging and Communications in Medicine format. These CT scans were converted into patient-specific 3-D computer models of the shoulder using Mimics software (Materialise Inc.). The use of this software to produce anatomically accurate models has previously been verified in a shoulder model.^6,7 The tuberosity fragments were then individually separated from each other using the voxel-selecting capabilities of 3-D software and manipulated with translation and rotation for anatomic reduction (Figures 1A-1D, Figure 2).

The de-identified anatomically reconstructed shoulder models were then uploaded into Materialise’s Magics rapid prototyping software, and a user-defined humeral Cartesian coordinate system was defined with anatomic landmarks as reference points to standardize the position of each model (Figure 3).^8,9 

A series of measurements were made on these models to assess the validity and reliability of the reassembly. The bicipital groove at the anatomic neck was used to measure humeral head version as described by Kummer and colleagues.¹⁰ The head-shaft angle, humeral head-greater tuberosity distance, humeral head-bicipital groove angle, and posterior and medial humeral head offset were measured directly on the reconstructed humerus.

Continue to: Two fellowship-trained shoulder...

STATISTICS

The measured dimensions of the 28 reassembled proximal humeri models were averaged across all trials between the 2 fellowship-trained surgeons and compared with the range of normal dimensions of a healthy proximal humerus using the 2 one-sided tests (TOST) method for equivalence between 2 means given a range. The interobserver and intraobserver reliabilities were quantified using the interclass correlation coefficient. An excellent correlation was defined as a correlation coefficient >0.81; very good was defined as 0.61 to 0.80; and good was defined as 0.41 to 0.60.

RESULTS

Of the patients studied, 9 (32.1%) were male, and the average age at the time of CT scanning was 72 years. Of the 28 patients with fracture, 18 (64.2%) had 3-part fractures (AO classifications 11-B1, 11-B2), and 10 (35.8%) had 4-part fractures (AO classifications 11-C1, 11-C2). When examining the location of the intertubercular fracture line, we found that 13 (46.4%) fractures went through the bicipital groove. Of the remaining fracture lines, 9 (32.1%) extended into the greater tuberosity and 6 (21.4%) extended into the lesser tuberosity.

All users were able to reconstruct all 28 fractures using this technique. The average measured dimensions fell within the range of dimensions of a normal healthy proximal humerus specified in the literature to within a 95% confidence interval using the TOST for equivalence, in which we compared measured values with ranges reported in the literature (Table).^11,12,13 

Table. Dimensions of Proximal Humerus Geometry

The reconstructions of these humerus fractures showed intraclass correlation coefficients ranging from 0.71 to 0.93 in 1 observer and interclass correlation coefficients from 0.82 to 0.98 between 2 different observers (Table).

DISCUSSION

This study demonstrates that it is feasible to reliably and accurately reconstruct the original anatomy of the proximal humerus by using 3-D computer modeling of proximal humerus fractures. Poor outcomes after hemiarthroplasty for proximal humerus fractures are mostly related to tuberosity malpositioning, resorption, or failure of fixation and resultant dysfunction of the rotator cuff.^14,15,16 These studies highlight the importance of accurate tuberosity reduction during surgical care of these fractures.

Continue to: The 3-D computer model...

Overreduction of greater tuberosity to create cortical overlap with the lateral shaft may be used to promote bony union. As a result of this distalization, there may be extra strains placed on the rotator cuff, making the patient more prone to rotator cuff tear, as well as improperly balancing the dynamic stabilizers of the shoulder. Poor clinical outcomes in hemiarthroplasty for proximal humerus fractures have been correlated with a greater tuberosity placed distal relative to the humeral head by 1 cm in a study² and by 2 cm in another.³

This study has several limitations. The first is the assumption that our injured patients had preinjury proximal humerus geometry within the range of normal dimensions of a healthy humerus. Unfortunately, because we were unable to obtain CT scans of the contralateral shoulder, we had to use standard proximal humerus geometry as the control. Another limitation, inherent in the technique, is that only cortical and dense trabecular bone was modeled, so that comminuted or osteoporotic bone was not well modeled. This study did not correlate the findings from these models with clinical outcomes. A prospective study is needed to evaluate the impact of this 3-D modeling on fracture reductions and clinical outcomes.

This study demonstrates that patient-specific modeling of proximal humerus fracture 3-D CT scans may help surgeons reliably and accurately reconstruct fractures. This technique may have utility in the preoperative planning of tuberosity fracture reduction and hemiarthroplasty. It gives surgeons the ability to visualize fracture fragments, and the process of reconstructing the fragments may help surgeons understand the required maneuvers for reduction at the time of surgery. This technique also provides dimensions of the patient’s native humerus, thus potentially improving the anatomic accuracy of the reduction or hemiarthroplasty reconstruction. With the new trend toward patient-specific instrumentation, this study also provides a means of planning the size of the humeral prostheses as well as the version relative to the biceps groove and intertubercular fracture line.

CONCLUSION

This study demonstrates the feasibility of using 3-D computer modeling of complex proximal humerus fractures in anatomic reconstruction. These techniques of computer-simulated 3-D models are valid and reliable. We believe that this technique of modeling and reconstructing proximal humerus fractures could be used to enhance the preoperative planning of hemiarthroplasty for 3- and 4-part proximal humerus fractures by providing improved understanding of the patient’s native humeral geometry and tuberosity reduction.

ABSTRACT

The reverse shoulder arthroplasty facilitates surgical treatment of primary and revision shoulder with rotator cuff and bone deficiencies. Wear pattern classifications and a logical treatment approach for glenoid bone loss enable the surgeon to address a difficult series of problems in the reconstructions where the glenoid might not otherwise be able to support the implants. Bone grafting using the native humeral head in primary cases, and in revision cases, iliac crest are the most reliable sources for structural grafts for the worn or deficient glenoid vault.

Continue to: The reverse shoulder arthroplasty...

The reverse shoulder arthroplasty (RSA) technique was approved by the US Food and Drug Administration and introduced to the US market in 2004. It has been a successful addition to the treatment of shoulder pathologies with bone and rotator cuff loss. Its indications have expanded from treatment of very elderly patients with rotator cuff deficiencies to now include younger patients with humeral and glenoid bone loss, arthritis, soft-tissue losses, fractures, instability, and revision arthroplasty. Many of these conditions, when not adequately addressed with anatomic arthroplasty, now have viable treatment options for newer complex and successful reconstructions.

Glenoid bone deficiencies offer unique challenges for successful arthroplasty management. Basing treatment on bone loss classifications permits meaningful evaluation of these surgical options and whether they might be carried out in 1- or 2-stage reconstructions. An underlying premise is that restoration of the glenoid joint line and version assist in final stability, power, and functional results. For this purpose, bone graft options, or augmented implants are beneficial. This review covers the bone grafting options for autografts and allografts for deficient glenoids in reverse shoulder arthroplasty reconstructions.

OPERATIVE TECHNIQUES

For patients without prior arthroplasty, the humeral head is available for bone grafting the glenoid bone deficits. Favard and Hamada have described vertical glenoid classifications for uneven glenoid bone loss applicable to cuff tear arthropathy and inflammatory arthritis patients.^1,2 The more severe E3 superior and medial bone loss is ideally addressed with the humeral head. An early example in 2004 confirmed that this was a good indication for glenoid bone grafting and using the reverse shoulder in these advanced cases (Figures 1A-1E).

In this case, it was noted that with bone grafts the base plate post did not engage the native scapula glenoid vault. Given that the on-growth central post was the strongest part of the fixation, it was fortunate that this healed. The need for a longer post with bone grafts was recognized. Laurent Comtat with the Wright Medical company accommodated the author’s request to develop the first 25- and 30-mm-long posts to allow better fixation and on-growth potential when used with bone grafts.

Gilles Walch’s classification addresses arthritic central and horizontal bone loss.^3,4 Considerations relevant in RSA include the severe A2 central bone loss found in inflammatory arthritis and the B2, B3, and C patterns with posterior bone loss seen in osteoarthritis, rheumatoid arthritis, and congenital dysplasia^5,6 as seen in Figures 2A, 2B. The 3-dimensional (3-D) computed tomography (CT) scan is considered the most accurate method of assessment when compared with axial radiographs.⁷ The glenoid vault model as a measurement of glenoid bone loss has great promise in designing prosthetic replacements and bone graft techniques.⁸

Continue to: Modern methods for determining glenoid version...

Modern methods for determining glenoid version, medialization, and eccentric bone wear include 3-D reconstruction and patient-specific instruments. For many years, version determination has been confirmed at surgery with subscapularis elevation, palpating the glenoid center point along Friedman’s line, and then inserting a Steinmann pin as a guide to restore version and the lateral joint line at the time of bone grafting. An example of this is demonstrated in Figures 3A-3E.⁹

All grafts are harvested with a hole saw from the humeral head. The inner diameter is 29 mm, the same as that of the base plate. Originally, the hole saw and mandrel were obtained from the hardware store, but Pascal Boileau upgraded the hole saw quality when he had industry develop a stainless-steel hole saw and published his results with the BIO-RSA (Wright Medical).¹⁰ In an unpublished study, Harmsen reviewed our 220 consecutive humeral head bone grafts for use of this technique with successful and reproducible results. In a separate evaluation, 29 shaped humeral head bone grafts for B2, B3, and C glenoid bone deficits showed 100% healing.¹¹ This technique has good reproducibility when performed with an autogenous bone graft from a local donor source.

The more challenging cases involve glenoid bone loss from polyethylene osteolysis and, in some revision cases, concomitant sepsis.¹² The humeral head is no longer available, and the distal clavicle or humeral metaphysis are often insufficient to restore the glenoid vault and joint line. Gunther and associates at the UC Berkeley biomaterials laboratory have made many contributions to our understanding of polyethylene wear and the factors leading to its loosening that result in massive glenoid bone loss.¹³

Antuna and colleagues¹⁴ classified these cases as having a central vault cavitary defect, or one combined with a peripheral glenoid wall bone loss of either the anterior or posterior glenoid. Newton and colleagues¹⁵ described the structural tricortical iliac crest bone graft as a 2-stage reconstruction. The second stage could be performed 4 to 6 months later after graft incorporation. With the excellent Association for Osteosynthesis (AO) type fixation using the base plate with compression and locking screws, it was reasonable to perform this in 1 stage, assuming that adequate fixation could be obtained with the iliac bone graft to the glenoid.¹⁶ This worked well with the cavitary glenoid defects and those in which either the anterior or posterior wall was absent.^17-19

EXCEPTIONS TO THE 1-STAGE FIXATION TECHNIQUE

Fixation could still be obtained medially, but more severe cases were encountered with loss of both the anterior and posterior walls. In these more advanced cases, the vault was no longer present after removal of the polyethylene, cement, and rubbery osteolytic tissue that replaced the bone. To account for this, a simplified 3-stage classification was proposed.²⁰ The cavitary vault defect is designated as type 1 bone loss. Type 2A includes the cavitary central defect plus loss of the anterior glenoid wall, and 2B is similar with loss of the posterior wall (Figures 4A-4F). Type 3 involves loss of the glenoid vault and both anterior and posterior walls with erosion down to the medial juncture of the base of the scapular spine, coracoid, and pillar of the scapula.

Continue to: The tricortical iliac crest bone graft...

The tricortical iliac crest bone graft (TICBG) offered a structural graft that worked well for these cases of bone loss. When the graft is performed in 1 stage, the glenoid is exposed, and the defect measured after removing the osteolytic, polyethylene-laden tissue from the glenoid. The iliac graft is harvested and placed with the long post base plate engaging the native scapula medially (Figures 5A-5C).

This technique worked well with the type 1 and 2 defects, but when attempted with the type 3 glenoid defect with global glenoid bone loss, adequate fixation for a single-stage reconstruction could not be predictably obtained with type 3 loss of the vault and both walls. In this situation, the base plate post is wider than the remaining medialized glenoid vault (Figures 6A-6C). The iliac crest provides better bone for this global loss when harvested sideways, fixed with screws, and after secure healing, the second-stage base plate is placed (Figures 7A-7F).

An alternative to the iliac crest as a bone graft donor site is the femoral neck allograft.²¹ It avoids the additional surgery and pain at the donor site, but healing is less assured. Scalise and Iannotti²² have had good clinical results but noted substantial graft resorption when revising a total shoulder to a humeral head arthroplasty. In a recent report by Ozgur and colleagues,²³ 64% of femoral neck allografts were still intact at 1-year follow-up. The technique involved harvesting the graft with a hole saw, shaping and affixing it to the deficient glenoid, and gaining central fixation with a threaded or solid post base plate and peripheral screws. Poor results were obtained with the use of the femoral shaft, as it is brittle. Angled peripheral screws caused the allograft shaft to fracture. Low-grade sepsis remained an unanswered problem in the patient group, which averaged 6 prior procedures, and often led to another revision. Less favorable results were found using the 1-piece threaded post base plate with grafts.²⁴ It is assumed that the allograft has less healing potential, and micro motion plays a role when the long central screw has no on-growth healing potential in the native scapula. This graft choice is the author’s least favorite, but is available in desperate situations. Jones and colleagues²⁵ report promising results with bulk allografts and autografts for large glenoid defects with good clinical results. The results in the graft cohort were inferior to those in a matched group not requiring grafts. Their complications were consistent with the revision setting for shoulders having multiple operations. It is well known that preoperative factors are strong predictors of postoperative outcomes.²⁶

CONCLUSION

The author’s current technique is to use the native humeral head when available, or iliac crest for structural support to the base plate and glenosphere. Secure fixation to the native scapula is necessary if the operation is to be done in 1-stage. Incorporation with calcium orthophosphate bone substitution does not replace the need for structural support as shown in Figures 8A-8D.

For the type 2 vault and 1 wall glenoid bone loss defects, the TICBG is still the most useful option. For the type 3 global bone loss defects, a 2-stage approach is the safer option. Additional options that may replace some of these grafting techniques are the introduction of the metallic augmented ingrowth base plates to correct for superior, anterior, and posterior glenoid bone losses. The early unpublished experiences by Wright and colleagues are very promising. All of the above options should be available in the operating room for a busy arthroplasty surgeon.

ABSTRACT

The reverse shoulder arthroplasty facilitates surgical treatment of primary and revision shoulder with rotator cuff and bone deficiencies. Wear pattern classifications and a logical treatment approach for glenoid bone loss enable the surgeon to address a difficult series of problems in the reconstructions where the glenoid might not otherwise be able to support the implants. Bone grafting using the native humeral head in primary cases, and in revision cases, iliac crest are the most reliable sources for structural grafts for the worn or deficient glenoid vault.

Continue to: The reverse shoulder arthroplasty...

The reverse shoulder arthroplasty (RSA) technique was approved by the US Food and Drug Administration and introduced to the US market in 2004. It has been a successful addition to the treatment of shoulder pathologies with bone and rotator cuff loss. Its indications have expanded from treatment of very elderly patients with rotator cuff deficiencies to now include younger patients with humeral and glenoid bone loss, arthritis, soft-tissue losses, fractures, instability, and revision arthroplasty. Many of these conditions, when not adequately addressed with anatomic arthroplasty, now have viable treatment options for newer complex and successful reconstructions.

Glenoid bone deficiencies offer unique challenges for successful arthroplasty management. Basing treatment on bone loss classifications permits meaningful evaluation of these surgical options and whether they might be carried out in 1- or 2-stage reconstructions. An underlying premise is that restoration of the glenoid joint line and version assist in final stability, power, and functional results. For this purpose, bone graft options, or augmented implants are beneficial. This review covers the bone grafting options for autografts and allografts for deficient glenoids in reverse shoulder arthroplasty reconstructions.

OPERATIVE TECHNIQUES

For patients without prior arthroplasty, the humeral head is available for bone grafting the glenoid bone deficits. Favard and Hamada have described vertical glenoid classifications for uneven glenoid bone loss applicable to cuff tear arthropathy and inflammatory arthritis patients.^1,2 The more severe E3 superior and medial bone loss is ideally addressed with the humeral head. An early example in 2004 confirmed that this was a good indication for glenoid bone grafting and using the reverse shoulder in these advanced cases (Figures 1A-1E).

In this case, it was noted that with bone grafts the base plate post did not engage the native scapula glenoid vault. Given that the on-growth central post was the strongest part of the fixation, it was fortunate that this healed. The need for a longer post with bone grafts was recognized. Laurent Comtat with the Wright Medical company accommodated the author’s request to develop the first 25- and 30-mm-long posts to allow better fixation and on-growth potential when used with bone grafts.

Gilles Walch’s classification addresses arthritic central and horizontal bone loss.^3,4 Considerations relevant in RSA include the severe A2 central bone loss found in inflammatory arthritis and the B2, B3, and C patterns with posterior bone loss seen in osteoarthritis, rheumatoid arthritis, and congenital dysplasia^5,6 as seen in Figures 2A, 2B. The 3-dimensional (3-D) computed tomography (CT) scan is considered the most accurate method of assessment when compared with axial radiographs.⁷ The glenoid vault model as a measurement of glenoid bone loss has great promise in designing prosthetic replacements and bone graft techniques.⁸

Continue to: Modern methods for determining glenoid version...

Modern methods for determining glenoid version, medialization, and eccentric bone wear include 3-D reconstruction and patient-specific instruments. For many years, version determination has been confirmed at surgery with subscapularis elevation, palpating the glenoid center point along Friedman’s line, and then inserting a Steinmann pin as a guide to restore version and the lateral joint line at the time of bone grafting. An example of this is demonstrated in Figures 3A-3E.⁹

All grafts are harvested with a hole saw from the humeral head. The inner diameter is 29 mm, the same as that of the base plate. Originally, the hole saw and mandrel were obtained from the hardware store, but Pascal Boileau upgraded the hole saw quality when he had industry develop a stainless-steel hole saw and published his results with the BIO-RSA (Wright Medical).¹⁰ In an unpublished study, Harmsen reviewed our 220 consecutive humeral head bone grafts for use of this technique with successful and reproducible results. In a separate evaluation, 29 shaped humeral head bone grafts for B2, B3, and C glenoid bone deficits showed 100% healing.¹¹ This technique has good reproducibility when performed with an autogenous bone graft from a local donor source.

The more challenging cases involve glenoid bone loss from polyethylene osteolysis and, in some revision cases, concomitant sepsis.¹² The humeral head is no longer available, and the distal clavicle or humeral metaphysis are often insufficient to restore the glenoid vault and joint line. Gunther and associates at the UC Berkeley biomaterials laboratory have made many contributions to our understanding of polyethylene wear and the factors leading to its loosening that result in massive glenoid bone loss.¹³

Antuna and colleagues¹⁴ classified these cases as having a central vault cavitary defect, or one combined with a peripheral glenoid wall bone loss of either the anterior or posterior glenoid. Newton and colleagues¹⁵ described the structural tricortical iliac crest bone graft as a 2-stage reconstruction. The second stage could be performed 4 to 6 months later after graft incorporation. With the excellent Association for Osteosynthesis (AO) type fixation using the base plate with compression and locking screws, it was reasonable to perform this in 1 stage, assuming that adequate fixation could be obtained with the iliac bone graft to the glenoid.¹⁶ This worked well with the cavitary glenoid defects and those in which either the anterior or posterior wall was absent.^17-19

EXCEPTIONS TO THE 1-STAGE FIXATION TECHNIQUE

Fixation could still be obtained medially, but more severe cases were encountered with loss of both the anterior and posterior walls. In these more advanced cases, the vault was no longer present after removal of the polyethylene, cement, and rubbery osteolytic tissue that replaced the bone. To account for this, a simplified 3-stage classification was proposed.²⁰ The cavitary vault defect is designated as type 1 bone loss. Type 2A includes the cavitary central defect plus loss of the anterior glenoid wall, and 2B is similar with loss of the posterior wall (Figures 4A-4F). Type 3 involves loss of the glenoid vault and both anterior and posterior walls with erosion down to the medial juncture of the base of the scapular spine, coracoid, and pillar of the scapula.

Continue to: The tricortical iliac crest bone graft...

The tricortical iliac crest bone graft (TICBG) offered a structural graft that worked well for these cases of bone loss. When the graft is performed in 1 stage, the glenoid is exposed, and the defect measured after removing the osteolytic, polyethylene-laden tissue from the glenoid. The iliac graft is harvested and placed with the long post base plate engaging the native scapula medially (Figures 5A-5C).

This technique worked well with the type 1 and 2 defects, but when attempted with the type 3 glenoid defect with global glenoid bone loss, adequate fixation for a single-stage reconstruction could not be predictably obtained with type 3 loss of the vault and both walls. In this situation, the base plate post is wider than the remaining medialized glenoid vault (Figures 6A-6C). The iliac crest provides better bone for this global loss when harvested sideways, fixed with screws, and after secure healing, the second-stage base plate is placed (Figures 7A-7F).

An alternative to the iliac crest as a bone graft donor site is the femoral neck allograft.²¹ It avoids the additional surgery and pain at the donor site, but healing is less assured. Scalise and Iannotti²² have had good clinical results but noted substantial graft resorption when revising a total shoulder to a humeral head arthroplasty. In a recent report by Ozgur and colleagues,²³ 64% of femoral neck allografts were still intact at 1-year follow-up. The technique involved harvesting the graft with a hole saw, shaping and affixing it to the deficient glenoid, and gaining central fixation with a threaded or solid post base plate and peripheral screws. Poor results were obtained with the use of the femoral shaft, as it is brittle. Angled peripheral screws caused the allograft shaft to fracture. Low-grade sepsis remained an unanswered problem in the patient group, which averaged 6 prior procedures, and often led to another revision. Less favorable results were found using the 1-piece threaded post base plate with grafts.²⁴ It is assumed that the allograft has less healing potential, and micro motion plays a role when the long central screw has no on-growth healing potential in the native scapula. This graft choice is the author’s least favorite, but is available in desperate situations. Jones and colleagues²⁵ report promising results with bulk allografts and autografts for large glenoid defects with good clinical results. The results in the graft cohort were inferior to those in a matched group not requiring grafts. Their complications were consistent with the revision setting for shoulders having multiple operations. It is well known that preoperative factors are strong predictors of postoperative outcomes.²⁶

CONCLUSION

The author’s current technique is to use the native humeral head when available, or iliac crest for structural support to the base plate and glenosphere. Secure fixation to the native scapula is necessary if the operation is to be done in 1-stage. Incorporation with calcium orthophosphate bone substitution does not replace the need for structural support as shown in Figures 8A-8D.

For the type 2 vault and 1 wall glenoid bone loss defects, the TICBG is still the most useful option. For the type 3 global bone loss defects, a 2-stage approach is the safer option. Additional options that may replace some of these grafting techniques are the introduction of the metallic augmented ingrowth base plates to correct for superior, anterior, and posterior glenoid bone losses. The early unpublished experiences by Wright and colleagues are very promising. All of the above options should be available in the operating room for a busy arthroplasty surgeon.

ABSTRACT

The reverse shoulder arthroplasty facilitates surgical treatment of primary and revision shoulder with rotator cuff and bone deficiencies. Wear pattern classifications and a logical treatment approach for glenoid bone loss enable the surgeon to address a difficult series of problems in the reconstructions where the glenoid might not otherwise be able to support the implants. Bone grafting using the native humeral head in primary cases, and in revision cases, iliac crest are the most reliable sources for structural grafts for the worn or deficient glenoid vault.

Continue to: The reverse shoulder arthroplasty...

The reverse shoulder arthroplasty (RSA) technique was approved by the US Food and Drug Administration and introduced to the US market in 2004. It has been a successful addition to the treatment of shoulder pathologies with bone and rotator cuff loss. Its indications have expanded from treatment of very elderly patients with rotator cuff deficiencies to now include younger patients with humeral and glenoid bone loss, arthritis, soft-tissue losses, fractures, instability, and revision arthroplasty. Many of these conditions, when not adequately addressed with anatomic arthroplasty, now have viable treatment options for newer complex and successful reconstructions.

Glenoid bone deficiencies offer unique challenges for successful arthroplasty management. Basing treatment on bone loss classifications permits meaningful evaluation of these surgical options and whether they might be carried out in 1- or 2-stage reconstructions. An underlying premise is that restoration of the glenoid joint line and version assist in final stability, power, and functional results. For this purpose, bone graft options, or augmented implants are beneficial. This review covers the bone grafting options for autografts and allografts for deficient glenoids in reverse shoulder arthroplasty reconstructions.

OPERATIVE TECHNIQUES

For patients without prior arthroplasty, the humeral head is available for bone grafting the glenoid bone deficits. Favard and Hamada have described vertical glenoid classifications for uneven glenoid bone loss applicable to cuff tear arthropathy and inflammatory arthritis patients.^1,2 The more severe E3 superior and medial bone loss is ideally addressed with the humeral head. An early example in 2004 confirmed that this was a good indication for glenoid bone grafting and using the reverse shoulder in these advanced cases (Figures 1A-1E).

In this case, it was noted that with bone grafts the base plate post did not engage the native scapula glenoid vault. Given that the on-growth central post was the strongest part of the fixation, it was fortunate that this healed. The need for a longer post with bone grafts was recognized. Laurent Comtat with the Wright Medical company accommodated the author’s request to develop the first 25- and 30-mm-long posts to allow better fixation and on-growth potential when used with bone grafts.

Gilles Walch’s classification addresses arthritic central and horizontal bone loss.^3,4 Considerations relevant in RSA include the severe A2 central bone loss found in inflammatory arthritis and the B2, B3, and C patterns with posterior bone loss seen in osteoarthritis, rheumatoid arthritis, and congenital dysplasia^5,6 as seen in Figures 2A, 2B. The 3-dimensional (3-D) computed tomography (CT) scan is considered the most accurate method of assessment when compared with axial radiographs.⁷ The glenoid vault model as a measurement of glenoid bone loss has great promise in designing prosthetic replacements and bone graft techniques.⁸

Continue to: Modern methods for determining glenoid version...

Modern methods for determining glenoid version, medialization, and eccentric bone wear include 3-D reconstruction and patient-specific instruments. For many years, version determination has been confirmed at surgery with subscapularis elevation, palpating the glenoid center point along Friedman’s line, and then inserting a Steinmann pin as a guide to restore version and the lateral joint line at the time of bone grafting. An example of this is demonstrated in Figures 3A-3E.⁹

All grafts are harvested with a hole saw from the humeral head. The inner diameter is 29 mm, the same as that of the base plate. Originally, the hole saw and mandrel were obtained from the hardware store, but Pascal Boileau upgraded the hole saw quality when he had industry develop a stainless-steel hole saw and published his results with the BIO-RSA (Wright Medical).¹⁰ In an unpublished study, Harmsen reviewed our 220 consecutive humeral head bone grafts for use of this technique with successful and reproducible results. In a separate evaluation, 29 shaped humeral head bone grafts for B2, B3, and C glenoid bone deficits showed 100% healing.¹¹ This technique has good reproducibility when performed with an autogenous bone graft from a local donor source.

The more challenging cases involve glenoid bone loss from polyethylene osteolysis and, in some revision cases, concomitant sepsis.¹² The humeral head is no longer available, and the distal clavicle or humeral metaphysis are often insufficient to restore the glenoid vault and joint line. Gunther and associates at the UC Berkeley biomaterials laboratory have made many contributions to our understanding of polyethylene wear and the factors leading to its loosening that result in massive glenoid bone loss.¹³

Antuna and colleagues¹⁴ classified these cases as having a central vault cavitary defect, or one combined with a peripheral glenoid wall bone loss of either the anterior or posterior glenoid. Newton and colleagues¹⁵ described the structural tricortical iliac crest bone graft as a 2-stage reconstruction. The second stage could be performed 4 to 6 months later after graft incorporation. With the excellent Association for Osteosynthesis (AO) type fixation using the base plate with compression and locking screws, it was reasonable to perform this in 1 stage, assuming that adequate fixation could be obtained with the iliac bone graft to the glenoid.¹⁶ This worked well with the cavitary glenoid defects and those in which either the anterior or posterior wall was absent.^17-19

EXCEPTIONS TO THE 1-STAGE FIXATION TECHNIQUE

Fixation could still be obtained medially, but more severe cases were encountered with loss of both the anterior and posterior walls. In these more advanced cases, the vault was no longer present after removal of the polyethylene, cement, and rubbery osteolytic tissue that replaced the bone. To account for this, a simplified 3-stage classification was proposed.²⁰ The cavitary vault defect is designated as type 1 bone loss. Type 2A includes the cavitary central defect plus loss of the anterior glenoid wall, and 2B is similar with loss of the posterior wall (Figures 4A-4F). Type 3 involves loss of the glenoid vault and both anterior and posterior walls with erosion down to the medial juncture of the base of the scapular spine, coracoid, and pillar of the scapula.

Continue to: The tricortical iliac crest bone graft...

The tricortical iliac crest bone graft (TICBG) offered a structural graft that worked well for these cases of bone loss. When the graft is performed in 1 stage, the glenoid is exposed, and the defect measured after removing the osteolytic, polyethylene-laden tissue from the glenoid. The iliac graft is harvested and placed with the long post base plate engaging the native scapula medially (Figures 5A-5C).

This technique worked well with the type 1 and 2 defects, but when attempted with the type 3 glenoid defect with global glenoid bone loss, adequate fixation for a single-stage reconstruction could not be predictably obtained with type 3 loss of the vault and both walls. In this situation, the base plate post is wider than the remaining medialized glenoid vault (Figures 6A-6C). The iliac crest provides better bone for this global loss when harvested sideways, fixed with screws, and after secure healing, the second-stage base plate is placed (Figures 7A-7F).

An alternative to the iliac crest as a bone graft donor site is the femoral neck allograft.²¹ It avoids the additional surgery and pain at the donor site, but healing is less assured. Scalise and Iannotti²² have had good clinical results but noted substantial graft resorption when revising a total shoulder to a humeral head arthroplasty. In a recent report by Ozgur and colleagues,²³ 64% of femoral neck allografts were still intact at 1-year follow-up. The technique involved harvesting the graft with a hole saw, shaping and affixing it to the deficient glenoid, and gaining central fixation with a threaded or solid post base plate and peripheral screws. Poor results were obtained with the use of the femoral shaft, as it is brittle. Angled peripheral screws caused the allograft shaft to fracture. Low-grade sepsis remained an unanswered problem in the patient group, which averaged 6 prior procedures, and often led to another revision. Less favorable results were found using the 1-piece threaded post base plate with grafts.²⁴ It is assumed that the allograft has less healing potential, and micro motion plays a role when the long central screw has no on-growth healing potential in the native scapula. This graft choice is the author’s least favorite, but is available in desperate situations. Jones and colleagues²⁵ report promising results with bulk allografts and autografts for large glenoid defects with good clinical results. The results in the graft cohort were inferior to those in a matched group not requiring grafts. Their complications were consistent with the revision setting for shoulders having multiple operations. It is well known that preoperative factors are strong predictors of postoperative outcomes.²⁶

CONCLUSION

The author’s current technique is to use the native humeral head when available, or iliac crest for structural support to the base plate and glenosphere. Secure fixation to the native scapula is necessary if the operation is to be done in 1-stage. Incorporation with calcium orthophosphate bone substitution does not replace the need for structural support as shown in Figures 8A-8D.

For the type 2 vault and 1 wall glenoid bone loss defects, the TICBG is still the most useful option. For the type 3 global bone loss defects, a 2-stage approach is the safer option. Additional options that may replace some of these grafting techniques are the introduction of the metallic augmented ingrowth base plates to correct for superior, anterior, and posterior glenoid bone losses. The early unpublished experiences by Wright and colleagues are very promising. All of the above options should be available in the operating room for a busy arthroplasty surgeon.

ABSTRACT

Glenoid bone deficiency in the setting of shoulder replacement surgery is far more common than originally reported. The frequency and severity of the glenoid defects are noted to be more common and severe with the advent of computer-assisted surgery. The results of an anatomic total shoulder arthroplasty (aTSA) with glenoid deficiency have been reported to be inferior to aTSA patients without a glenoid deficiency. Options for treating the glenoid deficiency include eccentric reaming, bone grafting, and the use of augmented glenoid components. The purpose of this article is to present the indications, technique, and results of augmented glenoids for both aTSA and reverse TSA (RTSA).

Augments for both aTSA and RTSA are viable options. They preserve subchondral bone at the same time as optimizing the joint line without the need for bone grafts. Complications, revisions and results are as good as compared to shoulder arthroplasties without glenoid wear.

Continue to: Glenoid bone deficiency...

Glenoid bone deficiency in arthritic or cuff-deficient shoulder has been reported in up to 50% of shoulder defect cases.^1,2 The type and severity of glenoid deformities vary depending on the underlying pathology and time of manifestation. Osteoarthritis with bone loss typically results in posterior or posterior inferior glenoid wear and is commonly classified as Walch types B1 or B2 (biconcave). In cases of severe erosion, B3 classification has been proposed; in this classification, bone loss becomes extremely severe, progressing to resemble a type C glenoid. Unlike primary osteoarthritis, inflammatory arthropathy more commonly causes central loss of glenoid bone (Walch A2). With the rotator cuff insufficiency, superior migration of the humeral head occurs. As these conditions progress, cuff tear arthropathy (CTA) changes result in superior or posterior-superior bone loss.¹ Anterior bone loss (type D) will be rarely encountered due to recurrent anterior instability.³

Classically, with anatomic total shoulder arthroplasty (aTSA), the surgeon considers several options for managing glenoid deficiencies. The most commonly employed technique involves eccentrically reaming the glenoid and correcting the deformity. This procedure is relatively easy but features significant drawbacks, such as sacrificing the subchondral bone, medializing the glenohumeral joint line, and secondarily shrinking the glenoid surface area. Other options include structural bone grafting behind the glenoid component. Most anatomic prosthetic glenoids prove to be unsuitable for fixation of structural bone graft. Therefore, the graft is first internally fixed, followed by placement of the glenoid component. Cement, which is commonly used for glenoid fixation, may potentially inhibit bone-graft healing. Reports using this technique documented high radiographic failure rate of up to 40% at midterm follow-up.⁴ Although leaving the glenoid component retroverted may be considered, surgeons should develop awareness of the possibility of peg penetration of the anterior glenoid neck. Additionally, retroversion in excess of 5°may increase the risk of recurrent posterior subluxation, resulting in early glenoid loosening.^5-7 Results of aTSA under significant glenoid deficiency are inferior to those of aTSA patients without glenoid deficiency.⁸ Such findings have been extremely inferior in patients with significant glenoid wear, prompting numerous surgeons to abandon aTSA in this population in favor of reverse TSA (RTSA) due to improved bony fixation.

In 2010, augmented anatomic glenoids were first introduced as a wedge (Exactech) and as a step shortly thereafter (DePuy Synthes; Figures 1A-1C). More recently, hemi-wedges have been introduced (Wright Medical Group). Augments have gained popularity due to improved range of motion vs reverse shoulder arthroplasty (RSA). However, debates remain regarding the use of posteriorly augmented components in the setting of posterior glenoid bone loss.⁸ Augments serve as another viable option for handling glenoid bone deficiency in aTSA.

Glenoid bone loss in RTSA presents similar options to aTSA. However, screw fixation of the glenoid component offers several distinct advantages. Baseplate fixation can readily be used with bone grafting and with a highly anticipated success rate. With multiple screw options, 100% support of the baseplate is not mandatory. Although bony increase offset RSAs (BIO-RSAs) have shown success, augmentation with allograft or autograft increases operative time and relies on osseous integration for long-term implant success.⁹ Metal augmented baseplates were first introduced in 2011 (Exactech) as a means of managing glenoid bone loss without structural grafting. Although initial results have been encouraging, additional studies are needed to assess the longevity of these implants (Figures 1A-1C).

aTSA AUGMENTS

aTSA augments were introduced as a means of correcting acquired glenoid bone deficiency, restoring native glenoid version, correcting humeral subluxation, and preserving the native subchondral bone. Compared with glenoid bone grafting, augmented glenoid components decrease operative time, allow for a technically easier operation, and require no bone healing for clinical success. Early and midterm results are encouraging, showing similar findings comparable to those of aTSA in non-glenoid deficient shoulders.^10-12

Continue to: INDICATIONS

Indications and limitations for augmented aTSA glenoids remain incompletely defined. The most common indication for an augmented aTSA is osteoarthritis with a B2 glenoid. We recommend augments in the occurrence of any indication of significant eccentric glenoid wear. With the expertise of surgeons, deformities of up to 20° to 25° of deformity can be readily handled with good predictability. More severe deformities can be managed with augmented aTSA components, but early failure rates may be high. The most severe acquired deformities remain best managed with RTSA. Currently, we prefer RTSA when glenoid bone loss exceeds 25°. With the widespread availability of computed tomography (CT) scans with 3-dimensional (3-D) reconstruction, glenoid bone defects are increasingly recognized. When correcting deformity, surgeons should strive to limit residual retroversion to a maximum of 5°.¹³ Preoperative planning software and computer-assisted surgery (ExactechGPS) may allow surgeons to better define the limits of augmented glenoid fixation prior to the date of surgery. We routinely utilize computer-guided glenoid preparation to control glenoid version to within 5° of neutral position.

The differences between B3 and a true type C glenoid must be recognized. Although B3 glenoids may still be a candidate for an augmented anatomic glenoid component, type C glenoids are not. Developmental abnormalities of type C glenoid occur simultaneously with humeral deformities, including medialized posterior rotator cuff musculature. Correction of the joint line to neutral version may not replicate the non-diseased state of a dysplastic type shoulder. Davis and colleagues¹⁴ have proposed treating these patients by leaving both the humerus and glenoid in their native version without correction.

TECHNIQUE

The implant that we have the most experience with is an 8° full-wedge augmented glenoid component. Such an implant is typically utilized for B2 glenoids. We recommend that a high-quality CT scan be performed for preoperative planning. As a general rule, the starting point often lies close to the ridge of B2 glenoid and more anterior than the apparent glenoid center, which is viewed intraoperatively due to asymmetric posterior wear. Full-wedge component is utilized to ream the ridge separating the neo and paleoglenoids to create a flat surface. This condition is best achieved by drilling a pilot hole at the planned glenoid central peg position to prevent the reamer from sliding anteriorly during reaming. Glenoid preparation begins with the smallest reamer until the ridge has been flattened, and the reamer makes full contact with the glenoid. The reamer diameter is then increased based on glenoid size. Slightly downsizing the glenoid implant will require less reaming to achieve full backside support. Once the glenoid is properly reamed, the central and peripheral peg holes are drilled using the appropriate guides. Holes are then dried, and all-polyethylene or composite glenoid component (either partially or completely cemented) is installed using favored cementing techniques. The advantage of composite glenoid component is that the central cage allows for bone ingrowth and may potentially improve long-term implant survival. Press fit of the central cage requires no waiting time for glenoid cement hardening before proceeding to the humerus. When placing an augmented component, adequate glenoid exposure is imperative to allow in-line placement and appropriate seating of the component without impingement on adjacent retractors.

When using the step-augmented glenoid, the paleoglenoid is prepared in a similar fashion to a standard aTSA. Once the paleoglenoid has been reamed to a neutral position, a protector plate is placed onto the paleoglenoid. and a step-cut saw is used to prepare the posterior stepped bone cut. Peripheral pegs are then drilled, and the component is installed in routine fashion. When using hemi-wedge augments, the paleoglenoid is again prepared in a similar fashion as a standard glenoid component over a cannulated guidewire. The neoglenoid is subsequently prepared using a specialized angled reamer with a positive stop to prevent over-reaming. These glenoid implants improve rotational force neutralization given the absence of flat back against the glenoid. All 3 designs preserve bone when compared with eccentric reaming alone,¹⁵ with the half-augmented wedge preserving the most bone.

Table 1. Results of Various Augmented Glenoid Components in Anatomic Total Shoulder

Arthroplasty

RESULTS

In our institution, we first used all-polyethylene posteriorly augmented glenoid components in 2010. Between 2010 and 2015, 45 patients received an 8° all-polyethylene posterior augment, and 7 patients received a 16° augment. In 2015, we transitioned to the composite caged posterior augment. All patients in our database who received an augmented glenoid component experienced improvement in active forward elevation, external rotation, American Shoulder and Elbow Surgeons (ASES), and Constant scores (Table 1). Minimum follow-up was 1 year for patients receiving both an 8° cage (mean, 1.48 years) and an 8° all-polyethylene augment (mean, 3.18 years). Figures 2A-2C show a patient with significant posterior glenoid wear and humeral head subluxation treated with an 8° wedge composite posterior augment glenoid 3 years postoperative.

Continue to: COMPLICATIONS

Two complications developed in the group undergoing composite cage augment. One patient experienced glenoid loosening after a motor vehicle accident. Another patient sustained significant intraoperative tuberosity avulsion during implantation of the humeral component, requiring a change of implant and tuberosity fixation. Although no complications were noted in the 8° all-polyethylene group, 3 patients in the 16° augment group sustained complications. One of these patients suffered a cardiac event that was unrelated to the implant. Two complications in this group were both related to loosening of the glenoid component, requiring subsequent revision.

DISCUSSION

The first report on augmented aTSA was published in 2008, and it involved a 5° augmented, anatomic glenoid.¹² One study was based on a small series of augments; the poor results led the reporting surgeons to subsequently abandon the implant.¹² This early design produced a correction on the articular side of the implant rather than the pathologic bony side. By performing such correction, the component pegs remained anteriorly oriented, placing the component at risk of perforation through the anterior glenoid neck. All current augment designs feature pegs that are oriented down the glenoid vault, with corrections occurring on the bony surface. This condition requires 2 different axes for reaming the glenoid and drilling the pegs. This approach allows the pegs to be directed down the glenoid neck, and is a far superior solution to neutralizing shear forces when compared with the implants used in the 1990s.

Early to midterm results of modern aTSA augments have been extremely encouraging with low revision rates. The main concern of recurrent posterior subluxation has been rarely reported. The concerns over glenoid loosening due to high shear forces, similarly, have not been described to date. However, surgeons should remain cautious, as longer-term follow-up remains unavailable.

The main advantage of aTSA augments is their capacity to preserve bone compared with eccentric reaming and better long-term stability. Each of the augment designs requires varying amounts of bone removal. Through biomechanics and using finite element analysis, the 3 augment types act differently, with no design demonstrating remarkable biomechanical superiority.⁶ Favorito and colleagues¹⁶ performed a retrospective review of 22 patients who underwent aTSA using an all-polyethylene, posteriorly augmented, and stepped glenoid component for posterior bone loss. At an average follow-up of 36 months, all patients experienced improvements in active forward elevation, external rotation, visual analog scale, Short Form-36 Physical Component Summary, and Western Ontario Osteoarthritis of the Shoulder scores. The authors noted that 2 patients (9%) experienced complications: 1 with an anterior dislocation and the other with recurrent posterior instability requiring revision. Sandow and Schutz¹⁷ reported the preliminary results of 10 patients who underwent aTSA using trabecular metal augment with a minimum of 2-year follow-up. All patients received either a 15° or 30° posterior, metal-backed augment for severe glenoid bone loss (Walch grade B2 or C). At a minimum of 2-year follow-up, all patients received correction to within 10° of neutral glenoid version, without any complications nor implant failures.

Regardless of augment design, all current components restore the native glenoid version, improving the length and subsequent tension of rotator cuff musculature. Similarly, re-centering the humeral head decreases the forces on the glenoid and allows for optimal function with decreasing loss of vital subchondral bone.  

Continue to: RTSA AUGMENTS

Similar to anatomic augments, metal augments were introduced for use with RTSA in 2011. Unlike anatomic augments, those for RTSA were manufactured with metal. Given the difference in bony wear patterns in patients requiring RTSA, augments were available in a number of configurations. With CTA, wear is most commonly superior. Leaving a superiorly inclined baseplate must be avoided due to risks of notching, loosening, and early failure. However, correcting this tilt will require significant reaming of the inferior glenoid. A superior augment is ideally suited for this bone-loss pattern. If the glenoid is retroverted significantly, difficulty can also arise during glenoid preparation and baseplate placement. Posterior augments may ease this aspect of the procedure. Posterior augments feature the additional benefits of tensioning any remaining posterior rotator cuff, minimizing posterior inferior impingement, and technically easing the operation.¹⁸ As we improve our awareness of glenoid orientation using computer navigation, a posterior-superior augmented implant is commonly needed to simultaneously optimize the baseplate position and to minimize reaming (Figure 3). The posterior-superior augmented baseplate has become the most commonly used baseplate augment of choice in 90% of our RTSA cases that require an augment.

INDICATIONS

Augmented RTSA baseplates are indicated when adequate backside contact cannot be achieved with eccentric reaming, thus compromising potential fixation. In our practice, we preferably use augments at <50% contact with the backside of the baseplate. Excessive superior inclination is observed in a CTA setting, commonly indicating the use of superior augments. Similarly, severe primary osteoarthritis may contain elements of posterior bone loss, leading to increased retroversion, which is where we use posterior augments. When patients exhibit combined deformities, or when the surgeon wishes to tension the posterior rotator cuff, a posterior-superior augmented glenoid baseplate is used. For extremely severe defects, we have combined bone grafting and augments. In patients with a highly deficient glenoid but good quality of the remaining bone stock, an augment allows for better contact with less reaming although it is not fully supported when compared with a non-augmented baseplate. Bone grafts can function similarly, but the autograft humeral head is not constantly present in revision situations and requires increased operative time to allow for precision carpentry. Additionally, the success of BIO-RSA requires healing of bone graft on the native glenoid to support the baseplate.¹⁹ Jones and colleagues⁹ compared metal augmented RTSA with BIO-RSA and presented equivalent results.

To minimize reaming and to obtain appropriately inferior inclination, we have discovered preoperative templating and intraoperative, computer-guided glenoid preparation to be extremely valuable (ExactechGPS). These tools allow appropriate assessment of augments and for minimal bone removal when preparing the glenoid.

TECHNIQUE

When using an augment, a fine-cut CT scan is highly recommended to aid in surgery planning. We also find 3-D reconstructions to be helpful. Preoperative planning software also allows surgeons to maximize fixation of implant within the glenoid vault. The starting point for reaming is planned based on CT. Some surgeons using augments perform minimal or no reaming at all, electing to remove the remaining cartilage with a Cobb elevator. Different reaming and drilling axes are used when using augments. In cases of severe glenoid deformity and unavailability of computer assistance, a guide wire with inferior inclination can be installed based on CT scan. Penetration of this wire down the glenoid neck can be palpated and compared with the preoperative plan. We generally prefer at least 24 mm of bone containment for the central cage. Once the surgeon is satisfied with the placement of the wire, the appropriate augment guide is placed, followed by a second guide wire. This second wire acts as the reaming axis. The first wire is removed, and the glenoid is reamed with a cannulated reamer. Once reaming is completed, the original wire is replaced in the same hole and trajectory, and the reaming wire is removed. The first wire is then drilled with a cannulated drill for the central cage. The augmented baseplate is then impacted into place, and screw fixation is performed. Again, intraoperative computer guidance allows for precision screw placement with maximal bone attachment.

Table 2. Results of Reverse Total Shoulder Arthroplasty Augmented Baseplates

RESULTS

Based on our experience, glenoid augments for RTSA have performed well at short- and mid-term follow-up. From October 2011 to July 2016, 139 patients undergoing RTSA received a posterior, superior, or posterior-superior augmented glenoid baseplate. All groups demonstrated improvements in functional outcome measures, including Constant, ASES, Shoulder Pain and Disability Index, and Simple Shoulder Test scores compared with baseline values (Table 2). The posterior-superior augment group experienced the most significant improvement in active forward flexion and external rotation, whereas the posterior augment group experienced the most significant improvement in ASES and Constant scores. Figures 4A-4C displays the radiographs of a patient with significant glenoid wear treated with a posterior-superior augment RTSA.

Continue to: COMPLICATIONS

In the superior augment group, 3 patients (13%) sustained 5 complications. One patient sustained 3 separate episodes of instability, eventually requiring revision of prosthesis. In the posterior augment group, 4 patients (8%) sustained complications. Two of the 4 patients presented postoperative humeral fractures related to traumatic events, whereas another patient sustained an intraoperative tuberosity fracture. The last complication in this group involved a postoperative draining wound that was treated with oral antibiotics.

Nine complications developed in the posterior-superior augment group (13%); these complications included aseptic baseplate loosening (5), glenoid fracture (1), humeral fracture (1), acromial stress fracture (1), and cerebrovascular accident (1).

DISCUSSION

As the use of augments in RTSA is relatively new, significantly scarce data exist regarding their outcomes and longevity. A few studies have focused on the short-term outcomes of these augments. Jones and colleagues⁹ performed a retrospective review of 80 patients who underwent RTSA and required either a structural bone graft or an augmented glenoid baseplate.⁹ They observed that although all patients showed improvements in pain, range of motion, and functional scores, the structural bone graft group incurred a 14.6% complication rate compared with none observed in the augment group. Additionally, Jones and colleagues⁹ noted that the augmented baseplate group exhibited a significantly lower rate of scapular notching compared with the bone-graft group (10% vs 18.5%) at similar follow-up intervals. A separate study by Wright and colleagues¹⁸ compared posterior vs superior augmented baseplates in RTSA. The posterior augment group demonstrated lower rates of scapular notching (6.3% vs 14.3%) and showed more significant improvements in Constant, ASES, and active forward elevation measures, compared with the superior augment group.

As more manufacturers develop augments for RTSA, and as ExactechGPS uses become more widespread, the use of RTSA baseplate augments will continually grow. Custom implants using massive metal augments are now also being introduced. Although currently too expensive for most cases, as technology drives the cost down, every patient may receive customized augmented implants in the future.

The advantages of augmented baseplate designs include minimized reaming and notching, improved tension of the remaining rotator cuff, and decreased operating room time. The disadvantages include increased cost and lack of mid- or long-term clinical data. The concerns with baseplate loosening with augments in RTSA are much less than those with augments for aTSA due to the outstanding baseplate fixation that can be achieved in RTSA.

Continue to: CONLCLUSION

Augments offer an excellent tool for surgeons performing both aTSA and RTSA with glenoid bone loss. Use of augments will become more common as more manufacturers develop them. Although clinical results fall short in full midterm, they have been positive for both augmented RTSA and aTSA. Concerns arise when performing augmented aTSA, as an upper limit of correction has not been defined with regard to component failure. Currently, no data support the maximum amount of correction that can be achieved. In our current practice, we face difficulty in correcting more than 25^° of version in young active patients with aTSA augment. Beyond this point, we perform a RTSA with an augment. In older patients or low-demand patients, we only correct minor deformities (<20^°) with an aTSA augment, opting instead for an augmented RTSA due to the lower midterm failure rates observed with this implant.

ABSTRACT

Glenoid bone deficiency in the setting of shoulder replacement surgery is far more common than originally reported. The frequency and severity of the glenoid defects are noted to be more common and severe with the advent of computer-assisted surgery. The results of an anatomic total shoulder arthroplasty (aTSA) with glenoid deficiency have been reported to be inferior to aTSA patients without a glenoid deficiency. Options for treating the glenoid deficiency include eccentric reaming, bone grafting, and the use of augmented glenoid components. The purpose of this article is to present the indications, technique, and results of augmented glenoids for both aTSA and reverse TSA (RTSA).

Augments for both aTSA and RTSA are viable options. They preserve subchondral bone at the same time as optimizing the joint line without the need for bone grafts. Complications, revisions and results are as good as compared to shoulder arthroplasties without glenoid wear.

Continue to: Glenoid bone deficiency...

Glenoid bone deficiency in arthritic or cuff-deficient shoulder has been reported in up to 50% of shoulder defect cases.^1,2 The type and severity of glenoid deformities vary depending on the underlying pathology and time of manifestation. Osteoarthritis with bone loss typically results in posterior or posterior inferior glenoid wear and is commonly classified as Walch types B1 or B2 (biconcave). In cases of severe erosion, B3 classification has been proposed; in this classification, bone loss becomes extremely severe, progressing to resemble a type C glenoid. Unlike primary osteoarthritis, inflammatory arthropathy more commonly causes central loss of glenoid bone (Walch A2). With the rotator cuff insufficiency, superior migration of the humeral head occurs. As these conditions progress, cuff tear arthropathy (CTA) changes result in superior or posterior-superior bone loss.¹ Anterior bone loss (type D) will be rarely encountered due to recurrent anterior instability.³

Classically, with anatomic total shoulder arthroplasty (aTSA), the surgeon considers several options for managing glenoid deficiencies. The most commonly employed technique involves eccentrically reaming the glenoid and correcting the deformity. This procedure is relatively easy but features significant drawbacks, such as sacrificing the subchondral bone, medializing the glenohumeral joint line, and secondarily shrinking the glenoid surface area. Other options include structural bone grafting behind the glenoid component. Most anatomic prosthetic glenoids prove to be unsuitable for fixation of structural bone graft. Therefore, the graft is first internally fixed, followed by placement of the glenoid component. Cement, which is commonly used for glenoid fixation, may potentially inhibit bone-graft healing. Reports using this technique documented high radiographic failure rate of up to 40% at midterm follow-up.⁴ Although leaving the glenoid component retroverted may be considered, surgeons should develop awareness of the possibility of peg penetration of the anterior glenoid neck. Additionally, retroversion in excess of 5°may increase the risk of recurrent posterior subluxation, resulting in early glenoid loosening.^5-7 Results of aTSA under significant glenoid deficiency are inferior to those of aTSA patients without glenoid deficiency.⁸ Such findings have been extremely inferior in patients with significant glenoid wear, prompting numerous surgeons to abandon aTSA in this population in favor of reverse TSA (RTSA) due to improved bony fixation.

In 2010, augmented anatomic glenoids were first introduced as a wedge (Exactech) and as a step shortly thereafter (DePuy Synthes; Figures 1A-1C). More recently, hemi-wedges have been introduced (Wright Medical Group). Augments have gained popularity due to improved range of motion vs reverse shoulder arthroplasty (RSA). However, debates remain regarding the use of posteriorly augmented components in the setting of posterior glenoid bone loss.⁸ Augments serve as another viable option for handling glenoid bone deficiency in aTSA.

Glenoid bone loss in RTSA presents similar options to aTSA. However, screw fixation of the glenoid component offers several distinct advantages. Baseplate fixation can readily be used with bone grafting and with a highly anticipated success rate. With multiple screw options, 100% support of the baseplate is not mandatory. Although bony increase offset RSAs (BIO-RSAs) have shown success, augmentation with allograft or autograft increases operative time and relies on osseous integration for long-term implant success.⁹ Metal augmented baseplates were first introduced in 2011 (Exactech) as a means of managing glenoid bone loss without structural grafting. Although initial results have been encouraging, additional studies are needed to assess the longevity of these implants (Figures 1A-1C).

aTSA AUGMENTS

aTSA augments were introduced as a means of correcting acquired glenoid bone deficiency, restoring native glenoid version, correcting humeral subluxation, and preserving the native subchondral bone. Compared with glenoid bone grafting, augmented glenoid components decrease operative time, allow for a technically easier operation, and require no bone healing for clinical success. Early and midterm results are encouraging, showing similar findings comparable to those of aTSA in non-glenoid deficient shoulders.^10-12

Continue to: INDICATIONS

Indications and limitations for augmented aTSA glenoids remain incompletely defined. The most common indication for an augmented aTSA is osteoarthritis with a B2 glenoid. We recommend augments in the occurrence of any indication of significant eccentric glenoid wear. With the expertise of surgeons, deformities of up to 20° to 25° of deformity can be readily handled with good predictability. More severe deformities can be managed with augmented aTSA components, but early failure rates may be high. The most severe acquired deformities remain best managed with RTSA. Currently, we prefer RTSA when glenoid bone loss exceeds 25°. With the widespread availability of computed tomography (CT) scans with 3-dimensional (3-D) reconstruction, glenoid bone defects are increasingly recognized. When correcting deformity, surgeons should strive to limit residual retroversion to a maximum of 5°.¹³ Preoperative planning software and computer-assisted surgery (ExactechGPS) may allow surgeons to better define the limits of augmented glenoid fixation prior to the date of surgery. We routinely utilize computer-guided glenoid preparation to control glenoid version to within 5° of neutral position.

The differences between B3 and a true type C glenoid must be recognized. Although B3 glenoids may still be a candidate for an augmented anatomic glenoid component, type C glenoids are not. Developmental abnormalities of type C glenoid occur simultaneously with humeral deformities, including medialized posterior rotator cuff musculature. Correction of the joint line to neutral version may not replicate the non-diseased state of a dysplastic type shoulder. Davis and colleagues¹⁴ have proposed treating these patients by leaving both the humerus and glenoid in their native version without correction.

TECHNIQUE

The implant that we have the most experience with is an 8° full-wedge augmented glenoid component. Such an implant is typically utilized for B2 glenoids. We recommend that a high-quality CT scan be performed for preoperative planning. As a general rule, the starting point often lies close to the ridge of B2 glenoid and more anterior than the apparent glenoid center, which is viewed intraoperatively due to asymmetric posterior wear. Full-wedge component is utilized to ream the ridge separating the neo and paleoglenoids to create a flat surface. This condition is best achieved by drilling a pilot hole at the planned glenoid central peg position to prevent the reamer from sliding anteriorly during reaming. Glenoid preparation begins with the smallest reamer until the ridge has been flattened, and the reamer makes full contact with the glenoid. The reamer diameter is then increased based on glenoid size. Slightly downsizing the glenoid implant will require less reaming to achieve full backside support. Once the glenoid is properly reamed, the central and peripheral peg holes are drilled using the appropriate guides. Holes are then dried, and all-polyethylene or composite glenoid component (either partially or completely cemented) is installed using favored cementing techniques. The advantage of composite glenoid component is that the central cage allows for bone ingrowth and may potentially improve long-term implant survival. Press fit of the central cage requires no waiting time for glenoid cement hardening before proceeding to the humerus. When placing an augmented component, adequate glenoid exposure is imperative to allow in-line placement and appropriate seating of the component without impingement on adjacent retractors.

When using the step-augmented glenoid, the paleoglenoid is prepared in a similar fashion to a standard aTSA. Once the paleoglenoid has been reamed to a neutral position, a protector plate is placed onto the paleoglenoid. and a step-cut saw is used to prepare the posterior stepped bone cut. Peripheral pegs are then drilled, and the component is installed in routine fashion. When using hemi-wedge augments, the paleoglenoid is again prepared in a similar fashion as a standard glenoid component over a cannulated guidewire. The neoglenoid is subsequently prepared using a specialized angled reamer with a positive stop to prevent over-reaming. These glenoid implants improve rotational force neutralization given the absence of flat back against the glenoid. All 3 designs preserve bone when compared with eccentric reaming alone,¹⁵ with the half-augmented wedge preserving the most bone.

Table 1. Results of Various Augmented Glenoid Components in Anatomic Total Shoulder

Arthroplasty

RESULTS

In our institution, we first used all-polyethylene posteriorly augmented glenoid components in 2010. Between 2010 and 2015, 45 patients received an 8° all-polyethylene posterior augment, and 7 patients received a 16° augment. In 2015, we transitioned to the composite caged posterior augment. All patients in our database who received an augmented glenoid component experienced improvement in active forward elevation, external rotation, American Shoulder and Elbow Surgeons (ASES), and Constant scores (Table 1). Minimum follow-up was 1 year for patients receiving both an 8° cage (mean, 1.48 years) and an 8° all-polyethylene augment (mean, 3.18 years). Figures 2A-2C show a patient with significant posterior glenoid wear and humeral head subluxation treated with an 8° wedge composite posterior augment glenoid 3 years postoperative.

Continue to: COMPLICATIONS

Two complications developed in the group undergoing composite cage augment. One patient experienced glenoid loosening after a motor vehicle accident. Another patient sustained significant intraoperative tuberosity avulsion during implantation of the humeral component, requiring a change of implant and tuberosity fixation. Although no complications were noted in the 8° all-polyethylene group, 3 patients in the 16° augment group sustained complications. One of these patients suffered a cardiac event that was unrelated to the implant. Two complications in this group were both related to loosening of the glenoid component, requiring subsequent revision.

DISCUSSION

The first report on augmented aTSA was published in 2008, and it involved a 5° augmented, anatomic glenoid.¹² One study was based on a small series of augments; the poor results led the reporting surgeons to subsequently abandon the implant.¹² This early design produced a correction on the articular side of the implant rather than the pathologic bony side. By performing such correction, the component pegs remained anteriorly oriented, placing the component at risk of perforation through the anterior glenoid neck. All current augment designs feature pegs that are oriented down the glenoid vault, with corrections occurring on the bony surface. This condition requires 2 different axes for reaming the glenoid and drilling the pegs. This approach allows the pegs to be directed down the glenoid neck, and is a far superior solution to neutralizing shear forces when compared with the implants used in the 1990s.

Early to midterm results of modern aTSA augments have been extremely encouraging with low revision rates. The main concern of recurrent posterior subluxation has been rarely reported. The concerns over glenoid loosening due to high shear forces, similarly, have not been described to date. However, surgeons should remain cautious, as longer-term follow-up remains unavailable.

The main advantage of aTSA augments is their capacity to preserve bone compared with eccentric reaming and better long-term stability. Each of the augment designs requires varying amounts of bone removal. Through biomechanics and using finite element analysis, the 3 augment types act differently, with no design demonstrating remarkable biomechanical superiority.⁶ Favorito and colleagues¹⁶ performed a retrospective review of 22 patients who underwent aTSA using an all-polyethylene, posteriorly augmented, and stepped glenoid component for posterior bone loss. At an average follow-up of 36 months, all patients experienced improvements in active forward elevation, external rotation, visual analog scale, Short Form-36 Physical Component Summary, and Western Ontario Osteoarthritis of the Shoulder scores. The authors noted that 2 patients (9%) experienced complications: 1 with an anterior dislocation and the other with recurrent posterior instability requiring revision. Sandow and Schutz¹⁷ reported the preliminary results of 10 patients who underwent aTSA using trabecular metal augment with a minimum of 2-year follow-up. All patients received either a 15° or 30° posterior, metal-backed augment for severe glenoid bone loss (Walch grade B2 or C). At a minimum of 2-year follow-up, all patients received correction to within 10° of neutral glenoid version, without any complications nor implant failures.

Regardless of augment design, all current components restore the native glenoid version, improving the length and subsequent tension of rotator cuff musculature. Similarly, re-centering the humeral head decreases the forces on the glenoid and allows for optimal function with decreasing loss of vital subchondral bone.  

Continue to: RTSA AUGMENTS

Similar to anatomic augments, metal augments were introduced for use with RTSA in 2011. Unlike anatomic augments, those for RTSA were manufactured with metal. Given the difference in bony wear patterns in patients requiring RTSA, augments were available in a number of configurations. With CTA, wear is most commonly superior. Leaving a superiorly inclined baseplate must be avoided due to risks of notching, loosening, and early failure. However, correcting this tilt will require significant reaming of the inferior glenoid. A superior augment is ideally suited for this bone-loss pattern. If the glenoid is retroverted significantly, difficulty can also arise during glenoid preparation and baseplate placement. Posterior augments may ease this aspect of the procedure. Posterior augments feature the additional benefits of tensioning any remaining posterior rotator cuff, minimizing posterior inferior impingement, and technically easing the operation.¹⁸ As we improve our awareness of glenoid orientation using computer navigation, a posterior-superior augmented implant is commonly needed to simultaneously optimize the baseplate position and to minimize reaming (Figure 3). The posterior-superior augmented baseplate has become the most commonly used baseplate augment of choice in 90% of our RTSA cases that require an augment.

INDICATIONS

Augmented RTSA baseplates are indicated when adequate backside contact cannot be achieved with eccentric reaming, thus compromising potential fixation. In our practice, we preferably use augments at <50% contact with the backside of the baseplate. Excessive superior inclination is observed in a CTA setting, commonly indicating the use of superior augments. Similarly, severe primary osteoarthritis may contain elements of posterior bone loss, leading to increased retroversion, which is where we use posterior augments. When patients exhibit combined deformities, or when the surgeon wishes to tension the posterior rotator cuff, a posterior-superior augmented glenoid baseplate is used. For extremely severe defects, we have combined bone grafting and augments. In patients with a highly deficient glenoid but good quality of the remaining bone stock, an augment allows for better contact with less reaming although it is not fully supported when compared with a non-augmented baseplate. Bone grafts can function similarly, but the autograft humeral head is not constantly present in revision situations and requires increased operative time to allow for precision carpentry. Additionally, the success of BIO-RSA requires healing of bone graft on the native glenoid to support the baseplate.¹⁹ Jones and colleagues⁹ compared metal augmented RTSA with BIO-RSA and presented equivalent results.

To minimize reaming and to obtain appropriately inferior inclination, we have discovered preoperative templating and intraoperative, computer-guided glenoid preparation to be extremely valuable (ExactechGPS). These tools allow appropriate assessment of augments and for minimal bone removal when preparing the glenoid.

TECHNIQUE

When using an augment, a fine-cut CT scan is highly recommended to aid in surgery planning. We also find 3-D reconstructions to be helpful. Preoperative planning software also allows surgeons to maximize fixation of implant within the glenoid vault. The starting point for reaming is planned based on CT. Some surgeons using augments perform minimal or no reaming at all, electing to remove the remaining cartilage with a Cobb elevator. Different reaming and drilling axes are used when using augments. In cases of severe glenoid deformity and unavailability of computer assistance, a guide wire with inferior inclination can be installed based on CT scan. Penetration of this wire down the glenoid neck can be palpated and compared with the preoperative plan. We generally prefer at least 24 mm of bone containment for the central cage. Once the surgeon is satisfied with the placement of the wire, the appropriate augment guide is placed, followed by a second guide wire. This second wire acts as the reaming axis. The first wire is removed, and the glenoid is reamed with a cannulated reamer. Once reaming is completed, the original wire is replaced in the same hole and trajectory, and the reaming wire is removed. The first wire is then drilled with a cannulated drill for the central cage. The augmented baseplate is then impacted into place, and screw fixation is performed. Again, intraoperative computer guidance allows for precision screw placement with maximal bone attachment.

Table 2. Results of Reverse Total Shoulder Arthroplasty Augmented Baseplates

RESULTS

Based on our experience, glenoid augments for RTSA have performed well at short- and mid-term follow-up. From October 2011 to July 2016, 139 patients undergoing RTSA received a posterior, superior, or posterior-superior augmented glenoid baseplate. All groups demonstrated improvements in functional outcome measures, including Constant, ASES, Shoulder Pain and Disability Index, and Simple Shoulder Test scores compared with baseline values (Table 2). The posterior-superior augment group experienced the most significant improvement in active forward flexion and external rotation, whereas the posterior augment group experienced the most significant improvement in ASES and Constant scores. Figures 4A-4C displays the radiographs of a patient with significant glenoid wear treated with a posterior-superior augment RTSA.

Continue to: COMPLICATIONS

In the superior augment group, 3 patients (13%) sustained 5 complications. One patient sustained 3 separate episodes of instability, eventually requiring revision of prosthesis. In the posterior augment group, 4 patients (8%) sustained complications. Two of the 4 patients presented postoperative humeral fractures related to traumatic events, whereas another patient sustained an intraoperative tuberosity fracture. The last complication in this group involved a postoperative draining wound that was treated with oral antibiotics.

Nine complications developed in the posterior-superior augment group (13%); these complications included aseptic baseplate loosening (5), glenoid fracture (1), humeral fracture (1), acromial stress fracture (1), and cerebrovascular accident (1).

DISCUSSION

As the use of augments in RTSA is relatively new, significantly scarce data exist regarding their outcomes and longevity. A few studies have focused on the short-term outcomes of these augments. Jones and colleagues⁹ performed a retrospective review of 80 patients who underwent RTSA and required either a structural bone graft or an augmented glenoid baseplate.⁹ They observed that although all patients showed improvements in pain, range of motion, and functional scores, the structural bone graft group incurred a 14.6% complication rate compared with none observed in the augment group. Additionally, Jones and colleagues⁹ noted that the augmented baseplate group exhibited a significantly lower rate of scapular notching compared with the bone-graft group (10% vs 18.5%) at similar follow-up intervals. A separate study by Wright and colleagues¹⁸ compared posterior vs superior augmented baseplates in RTSA. The posterior augment group demonstrated lower rates of scapular notching (6.3% vs 14.3%) and showed more significant improvements in Constant, ASES, and active forward elevation measures, compared with the superior augment group.

As more manufacturers develop augments for RTSA, and as ExactechGPS uses become more widespread, the use of RTSA baseplate augments will continually grow. Custom implants using massive metal augments are now also being introduced. Although currently too expensive for most cases, as technology drives the cost down, every patient may receive customized augmented implants in the future.

The advantages of augmented baseplate designs include minimized reaming and notching, improved tension of the remaining rotator cuff, and decreased operating room time. The disadvantages include increased cost and lack of mid- or long-term clinical data. The concerns with baseplate loosening with augments in RTSA are much less than those with augments for aTSA due to the outstanding baseplate fixation that can be achieved in RTSA.

Continue to: CONLCLUSION

Augments offer an excellent tool for surgeons performing both aTSA and RTSA with glenoid bone loss. Use of augments will become more common as more manufacturers develop them. Although clinical results fall short in full midterm, they have been positive for both augmented RTSA and aTSA. Concerns arise when performing augmented aTSA, as an upper limit of correction has not been defined with regard to component failure. Currently, no data support the maximum amount of correction that can be achieved. In our current practice, we face difficulty in correcting more than 25^° of version in young active patients with aTSA augment. Beyond this point, we perform a RTSA with an augment. In older patients or low-demand patients, we only correct minor deformities (<20^°) with an aTSA augment, opting instead for an augmented RTSA due to the lower midterm failure rates observed with this implant.

ABSTRACT

Glenoid bone deficiency in the setting of shoulder replacement surgery is far more common than originally reported. The frequency and severity of the glenoid defects are noted to be more common and severe with the advent of computer-assisted surgery. The results of an anatomic total shoulder arthroplasty (aTSA) with glenoid deficiency have been reported to be inferior to aTSA patients without a glenoid deficiency. Options for treating the glenoid deficiency include eccentric reaming, bone grafting, and the use of augmented glenoid components. The purpose of this article is to present the indications, technique, and results of augmented glenoids for both aTSA and reverse TSA (RTSA).

Augments for both aTSA and RTSA are viable options. They preserve subchondral bone at the same time as optimizing the joint line without the need for bone grafts. Complications, revisions and results are as good as compared to shoulder arthroplasties without glenoid wear.

Continue to: Glenoid bone deficiency...

Glenoid bone deficiency in arthritic or cuff-deficient shoulder has been reported in up to 50% of shoulder defect cases.^1,2 The type and severity of glenoid deformities vary depending on the underlying pathology and time of manifestation. Osteoarthritis with bone loss typically results in posterior or posterior inferior glenoid wear and is commonly classified as Walch types B1 or B2 (biconcave). In cases of severe erosion, B3 classification has been proposed; in this classification, bone loss becomes extremely severe, progressing to resemble a type C glenoid. Unlike primary osteoarthritis, inflammatory arthropathy more commonly causes central loss of glenoid bone (Walch A2). With the rotator cuff insufficiency, superior migration of the humeral head occurs. As these conditions progress, cuff tear arthropathy (CTA) changes result in superior or posterior-superior bone loss.¹ Anterior bone loss (type D) will be rarely encountered due to recurrent anterior instability.³

Classically, with anatomic total shoulder arthroplasty (aTSA), the surgeon considers several options for managing glenoid deficiencies. The most commonly employed technique involves eccentrically reaming the glenoid and correcting the deformity. This procedure is relatively easy but features significant drawbacks, such as sacrificing the subchondral bone, medializing the glenohumeral joint line, and secondarily shrinking the glenoid surface area. Other options include structural bone grafting behind the glenoid component. Most anatomic prosthetic glenoids prove to be unsuitable for fixation of structural bone graft. Therefore, the graft is first internally fixed, followed by placement of the glenoid component. Cement, which is commonly used for glenoid fixation, may potentially inhibit bone-graft healing. Reports using this technique documented high radiographic failure rate of up to 40% at midterm follow-up.⁴ Although leaving the glenoid component retroverted may be considered, surgeons should develop awareness of the possibility of peg penetration of the anterior glenoid neck. Additionally, retroversion in excess of 5°may increase the risk of recurrent posterior subluxation, resulting in early glenoid loosening.^5-7 Results of aTSA under significant glenoid deficiency are inferior to those of aTSA patients without glenoid deficiency.⁸ Such findings have been extremely inferior in patients with significant glenoid wear, prompting numerous surgeons to abandon aTSA in this population in favor of reverse TSA (RTSA) due to improved bony fixation.

In 2010, augmented anatomic glenoids were first introduced as a wedge (Exactech) and as a step shortly thereafter (DePuy Synthes; Figures 1A-1C). More recently, hemi-wedges have been introduced (Wright Medical Group). Augments have gained popularity due to improved range of motion vs reverse shoulder arthroplasty (RSA). However, debates remain regarding the use of posteriorly augmented components in the setting of posterior glenoid bone loss.⁸ Augments serve as another viable option for handling glenoid bone deficiency in aTSA.

Glenoid bone loss in RTSA presents similar options to aTSA. However, screw fixation of the glenoid component offers several distinct advantages. Baseplate fixation can readily be used with bone grafting and with a highly anticipated success rate. With multiple screw options, 100% support of the baseplate is not mandatory. Although bony increase offset RSAs (BIO-RSAs) have shown success, augmentation with allograft or autograft increases operative time and relies on osseous integration for long-term implant success.⁹ Metal augmented baseplates were first introduced in 2011 (Exactech) as a means of managing glenoid bone loss without structural grafting. Although initial results have been encouraging, additional studies are needed to assess the longevity of these implants (Figures 1A-1C).

aTSA AUGMENTS

aTSA augments were introduced as a means of correcting acquired glenoid bone deficiency, restoring native glenoid version, correcting humeral subluxation, and preserving the native subchondral bone. Compared with glenoid bone grafting, augmented glenoid components decrease operative time, allow for a technically easier operation, and require no bone healing for clinical success. Early and midterm results are encouraging, showing similar findings comparable to those of aTSA in non-glenoid deficient shoulders.^10-12

Continue to: INDICATIONS

Indications and limitations for augmented aTSA glenoids remain incompletely defined. The most common indication for an augmented aTSA is osteoarthritis with a B2 glenoid. We recommend augments in the occurrence of any indication of significant eccentric glenoid wear. With the expertise of surgeons, deformities of up to 20° to 25° of deformity can be readily handled with good predictability. More severe deformities can be managed with augmented aTSA components, but early failure rates may be high. The most severe acquired deformities remain best managed with RTSA. Currently, we prefer RTSA when glenoid bone loss exceeds 25°. With the widespread availability of computed tomography (CT) scans with 3-dimensional (3-D) reconstruction, glenoid bone defects are increasingly recognized. When correcting deformity, surgeons should strive to limit residual retroversion to a maximum of 5°.¹³ Preoperative planning software and computer-assisted surgery (ExactechGPS) may allow surgeons to better define the limits of augmented glenoid fixation prior to the date of surgery. We routinely utilize computer-guided glenoid preparation to control glenoid version to within 5° of neutral position.

The differences between B3 and a true type C glenoid must be recognized. Although B3 glenoids may still be a candidate for an augmented anatomic glenoid component, type C glenoids are not. Developmental abnormalities of type C glenoid occur simultaneously with humeral deformities, including medialized posterior rotator cuff musculature. Correction of the joint line to neutral version may not replicate the non-diseased state of a dysplastic type shoulder. Davis and colleagues¹⁴ have proposed treating these patients by leaving both the humerus and glenoid in their native version without correction.

TECHNIQUE

The implant that we have the most experience with is an 8° full-wedge augmented glenoid component. Such an implant is typically utilized for B2 glenoids. We recommend that a high-quality CT scan be performed for preoperative planning. As a general rule, the starting point often lies close to the ridge of B2 glenoid and more anterior than the apparent glenoid center, which is viewed intraoperatively due to asymmetric posterior wear. Full-wedge component is utilized to ream the ridge separating the neo and paleoglenoids to create a flat surface. This condition is best achieved by drilling a pilot hole at the planned glenoid central peg position to prevent the reamer from sliding anteriorly during reaming. Glenoid preparation begins with the smallest reamer until the ridge has been flattened, and the reamer makes full contact with the glenoid. The reamer diameter is then increased based on glenoid size. Slightly downsizing the glenoid implant will require less reaming to achieve full backside support. Once the glenoid is properly reamed, the central and peripheral peg holes are drilled using the appropriate guides. Holes are then dried, and all-polyethylene or composite glenoid component (either partially or completely cemented) is installed using favored cementing techniques. The advantage of composite glenoid component is that the central cage allows for bone ingrowth and may potentially improve long-term implant survival. Press fit of the central cage requires no waiting time for glenoid cement hardening before proceeding to the humerus. When placing an augmented component, adequate glenoid exposure is imperative to allow in-line placement and appropriate seating of the component without impingement on adjacent retractors.

When using the step-augmented glenoid, the paleoglenoid is prepared in a similar fashion to a standard aTSA. Once the paleoglenoid has been reamed to a neutral position, a protector plate is placed onto the paleoglenoid. and a step-cut saw is used to prepare the posterior stepped bone cut. Peripheral pegs are then drilled, and the component is installed in routine fashion. When using hemi-wedge augments, the paleoglenoid is again prepared in a similar fashion as a standard glenoid component over a cannulated guidewire. The neoglenoid is subsequently prepared using a specialized angled reamer with a positive stop to prevent over-reaming. These glenoid implants improve rotational force neutralization given the absence of flat back against the glenoid. All 3 designs preserve bone when compared with eccentric reaming alone,¹⁵ with the half-augmented wedge preserving the most bone.

Table 1. Results of Various Augmented Glenoid Components in Anatomic Total Shoulder

Arthroplasty

RESULTS

In our institution, we first used all-polyethylene posteriorly augmented glenoid components in 2010. Between 2010 and 2015, 45 patients received an 8° all-polyethylene posterior augment, and 7 patients received a 16° augment. In 2015, we transitioned to the composite caged posterior augment. All patients in our database who received an augmented glenoid component experienced improvement in active forward elevation, external rotation, American Shoulder and Elbow Surgeons (ASES), and Constant scores (Table 1). Minimum follow-up was 1 year for patients receiving both an 8° cage (mean, 1.48 years) and an 8° all-polyethylene augment (mean, 3.18 years). Figures 2A-2C show a patient with significant posterior glenoid wear and humeral head subluxation treated with an 8° wedge composite posterior augment glenoid 3 years postoperative.

Continue to: COMPLICATIONS

Two complications developed in the group undergoing composite cage augment. One patient experienced glenoid loosening after a motor vehicle accident. Another patient sustained significant intraoperative tuberosity avulsion during implantation of the humeral component, requiring a change of implant and tuberosity fixation. Although no complications were noted in the 8° all-polyethylene group, 3 patients in the 16° augment group sustained complications. One of these patients suffered a cardiac event that was unrelated to the implant. Two complications in this group were both related to loosening of the glenoid component, requiring subsequent revision.

DISCUSSION

The first report on augmented aTSA was published in 2008, and it involved a 5° augmented, anatomic glenoid.¹² One study was based on a small series of augments; the poor results led the reporting surgeons to subsequently abandon the implant.¹² This early design produced a correction on the articular side of the implant rather than the pathologic bony side. By performing such correction, the component pegs remained anteriorly oriented, placing the component at risk of perforation through the anterior glenoid neck. All current augment designs feature pegs that are oriented down the glenoid vault, with corrections occurring on the bony surface. This condition requires 2 different axes for reaming the glenoid and drilling the pegs. This approach allows the pegs to be directed down the glenoid neck, and is a far superior solution to neutralizing shear forces when compared with the implants used in the 1990s.

Early to midterm results of modern aTSA augments have been extremely encouraging with low revision rates. The main concern of recurrent posterior subluxation has been rarely reported. The concerns over glenoid loosening due to high shear forces, similarly, have not been described to date. However, surgeons should remain cautious, as longer-term follow-up remains unavailable.

The main advantage of aTSA augments is their capacity to preserve bone compared with eccentric reaming and better long-term stability. Each of the augment designs requires varying amounts of bone removal. Through biomechanics and using finite element analysis, the 3 augment types act differently, with no design demonstrating remarkable biomechanical superiority.⁶ Favorito and colleagues¹⁶ performed a retrospective review of 22 patients who underwent aTSA using an all-polyethylene, posteriorly augmented, and stepped glenoid component for posterior bone loss. At an average follow-up of 36 months, all patients experienced improvements in active forward elevation, external rotation, visual analog scale, Short Form-36 Physical Component Summary, and Western Ontario Osteoarthritis of the Shoulder scores. The authors noted that 2 patients (9%) experienced complications: 1 with an anterior dislocation and the other with recurrent posterior instability requiring revision. Sandow and Schutz¹⁷ reported the preliminary results of 10 patients who underwent aTSA using trabecular metal augment with a minimum of 2-year follow-up. All patients received either a 15° or 30° posterior, metal-backed augment for severe glenoid bone loss (Walch grade B2 or C). At a minimum of 2-year follow-up, all patients received correction to within 10° of neutral glenoid version, without any complications nor implant failures.

Regardless of augment design, all current components restore the native glenoid version, improving the length and subsequent tension of rotator cuff musculature. Similarly, re-centering the humeral head decreases the forces on the glenoid and allows for optimal function with decreasing loss of vital subchondral bone.  

Continue to: RTSA AUGMENTS

Similar to anatomic augments, metal augments were introduced for use with RTSA in 2011. Unlike anatomic augments, those for RTSA were manufactured with metal. Given the difference in bony wear patterns in patients requiring RTSA, augments were available in a number of configurations. With CTA, wear is most commonly superior. Leaving a superiorly inclined baseplate must be avoided due to risks of notching, loosening, and early failure. However, correcting this tilt will require significant reaming of the inferior glenoid. A superior augment is ideally suited for this bone-loss pattern. If the glenoid is retroverted significantly, difficulty can also arise during glenoid preparation and baseplate placement. Posterior augments may ease this aspect of the procedure. Posterior augments feature the additional benefits of tensioning any remaining posterior rotator cuff, minimizing posterior inferior impingement, and technically easing the operation.¹⁸ As we improve our awareness of glenoid orientation using computer navigation, a posterior-superior augmented implant is commonly needed to simultaneously optimize the baseplate position and to minimize reaming (Figure 3). The posterior-superior augmented baseplate has become the most commonly used baseplate augment of choice in 90% of our RTSA cases that require an augment.

INDICATIONS

Augmented RTSA baseplates are indicated when adequate backside contact cannot be achieved with eccentric reaming, thus compromising potential fixation. In our practice, we preferably use augments at <50% contact with the backside of the baseplate. Excessive superior inclination is observed in a CTA setting, commonly indicating the use of superior augments. Similarly, severe primary osteoarthritis may contain elements of posterior bone loss, leading to increased retroversion, which is where we use posterior augments. When patients exhibit combined deformities, or when the surgeon wishes to tension the posterior rotator cuff, a posterior-superior augmented glenoid baseplate is used. For extremely severe defects, we have combined bone grafting and augments. In patients with a highly deficient glenoid but good quality of the remaining bone stock, an augment allows for better contact with less reaming although it is not fully supported when compared with a non-augmented baseplate. Bone grafts can function similarly, but the autograft humeral head is not constantly present in revision situations and requires increased operative time to allow for precision carpentry. Additionally, the success of BIO-RSA requires healing of bone graft on the native glenoid to support the baseplate.¹⁹ Jones and colleagues⁹ compared metal augmented RTSA with BIO-RSA and presented equivalent results.

To minimize reaming and to obtain appropriately inferior inclination, we have discovered preoperative templating and intraoperative, computer-guided glenoid preparation to be extremely valuable (ExactechGPS). These tools allow appropriate assessment of augments and for minimal bone removal when preparing the glenoid.

TECHNIQUE

When using an augment, a fine-cut CT scan is highly recommended to aid in surgery planning. We also find 3-D reconstructions to be helpful. Preoperative planning software also allows surgeons to maximize fixation of implant within the glenoid vault. The starting point for reaming is planned based on CT. Some surgeons using augments perform minimal or no reaming at all, electing to remove the remaining cartilage with a Cobb elevator. Different reaming and drilling axes are used when using augments. In cases of severe glenoid deformity and unavailability of computer assistance, a guide wire with inferior inclination can be installed based on CT scan. Penetration of this wire down the glenoid neck can be palpated and compared with the preoperative plan. We generally prefer at least 24 mm of bone containment for the central cage. Once the surgeon is satisfied with the placement of the wire, the appropriate augment guide is placed, followed by a second guide wire. This second wire acts as the reaming axis. The first wire is removed, and the glenoid is reamed with a cannulated reamer. Once reaming is completed, the original wire is replaced in the same hole and trajectory, and the reaming wire is removed. The first wire is then drilled with a cannulated drill for the central cage. The augmented baseplate is then impacted into place, and screw fixation is performed. Again, intraoperative computer guidance allows for precision screw placement with maximal bone attachment.

Table 2. Results of Reverse Total Shoulder Arthroplasty Augmented Baseplates

RESULTS

Based on our experience, glenoid augments for RTSA have performed well at short- and mid-term follow-up. From October 2011 to July 2016, 139 patients undergoing RTSA received a posterior, superior, or posterior-superior augmented glenoid baseplate. All groups demonstrated improvements in functional outcome measures, including Constant, ASES, Shoulder Pain and Disability Index, and Simple Shoulder Test scores compared with baseline values (Table 2). The posterior-superior augment group experienced the most significant improvement in active forward flexion and external rotation, whereas the posterior augment group experienced the most significant improvement in ASES and Constant scores. Figures 4A-4C displays the radiographs of a patient with significant glenoid wear treated with a posterior-superior augment RTSA.

Continue to: COMPLICATIONS