Outcomes
Coracoid bone transfer or the Bristow-Latarjet technique has become more popular since bone loss was recognized as an important cause of failure of soft-tissue repair for anterior instability. This procedure, however, is not without complications. In a recent systematic review of 45 studies (1904 shoulders), Griesser and colleagues5 found an overall complication rate of 30% and a reoperation rate of 7%.
Given the potential complications of coracoid bone transfer, allograft reconstruction of the anteroinferior glenoid has become increasingly popular and proved successful at short- and medium-term follow-up. Allograft reconstruction avoids the drawbacks of traditional coracoid bone transfer—namely, high rates of neurovascular injury, and nonanatomical reconstruction with high rates of graft resorption and arthritis.5,6 At average 45-month follow-up after fresh distal tibia allograft reconstruction, Provencher and colleagues7 found an 89% radiographic union rate (average lysis, 3%), significantly improved patient-reported outcomes, and no recurrent instability. Similarly, in a study of iliac crest allograft reconstruction in 10 patients with an average 4-year follow-up, Mascarenhas and colleagues8 found an 80% radiographic union rate at 6 months, significantly improved patient-reported outcomes, and no recurrent shoulder instability.
The advantage of Glenojet over other allografts is that it is preshaped and predrilled and saves the surgeon the time and effort of preparing graft in the operating room. The surgical technologist can place the sutures before the patient enters the room. The 2 allograft sizes (10 mm × 29 mm, 13 mm × 34 mm) accommodate the spectrum of bone loss in glenoid deficiency, and graft contour fits the native glenoid well. So far we have implanted this allograft in 15 patients, and at short-term follow-up there are no known cases of recurrent instability.
The potential disadvantages of Glenojet are similar to those of other allografts. Care must be taken with retractor placement to avoid damaging the axillary and musculocutaneous nerves. There are concerns about graft union and subsequent resorption, but this will require long-term follow-up to determine. At 9-month follow-up, we had 1 fracture at the superior corner of the graft, which may have resulted from overtightening the screws in the graft, creating a stress concentration. After removal of this fragment arthroscopically, the patient has done very well clinically with no pain, instability and has returned to all activities. Although the graft does not have an articular surface, the capsular repair covers much of the articular side of the graft, and therefore we do not anticipate that the absence of articular cartilage will contribute to glenohumeral arthritis, though long-term follow-up is lacking. The other question many have is related to the lack of the sling effect since there is no conjoined tendon on the graft. Yamamoto and colleagues9 have reported that the conjoined tendon is the major stabilizing force at time zero in a cadaver model. However, other authors7,8 have successfully reconstructed glenoid defects in these difficult cases without the “sling effect” of the conjoined tendon with excellent clinical results. Our experience has been similar. It is likely that long-term studies will be necessary to answer this question. We have also done some cases with the tendon attached after releasing it from the coracoid, but the series is too small to make any comment about whether this is important or not.
The main limitation of this allograft technique is the lack of long-term outcome studies. However, short-term results are promising, and the ease of the procedure makes it an attractive option for either glenoid reconstruction of bony Bankart lesions or failed bone reconstruction, such as Bristow-Latarjet reconstruction.
Glenojetallograft is a new glenoid reconstruction option that is technically easy and simple to perform in cases of glenoid bone loss, while still creating an anatomical buttress with less surgical dissection than traditional coracoid bone transfer. Short-term outcomes are reassuring, though more research is needed for long-term graft follow-up and recurrent instability.
Am J Orthop. 2017;46(4):199-202. Copyright Frontline Medical Communications Inc. 2017. All rights reserved.