Treatment of Cartilage Lesions
The indications and contraindications for hip arthroscopy in patients with cartilage lesions are important. Our study’s 5-year outcomes of treating FAI with hip arthroscopy in patients with preserved joint space (>2 mm) were promising, though 86% of patients with limited joint space (≤2 mm) converted to total hip arthroplasty.8 We regard patients with severe osteoarthritis as not being candidates for hip arthroscopy.
As 3 Tesla magnetic resonance imaging has low positive predictive value in identifying severe cartilage damage,13 the cartilage should be examined during surgery to further define the diagnosis. Nearly half of the hip arthroscopy patients in our study had at least 1 Outerbridge grade 3 or 4 cartilage lesion.14 Compared with the femoral head, acetabular cartilage was damaged 3 times more often. More than 90% of acetabular cartilage lesions were in the anterosuperior region.
Grades 0 and 1 cartilage lesions are usually left untreated; no intervention is necessary. Grades 2 and 3 cartilage lesions are reduced by partial débridement and/or thermal shrinkage. With the improved joint microenvironment arising from simple correction of the underlying hip bony abnormalities, these lesions should not produce further symptoms.
Grade 4 hip cartilage defects are challenging. We prefer microfracture for grade 4 lesions (Figure 4).
A ring curette is used to prepare the defect, and perpendicular borders are created to hold the clot in place. Deep débridement removes the calcified layer while maintaining the integrity of the subchondral plate.15 As a recent study found microfracture performed with small-diameter awls improved cartilage repair more effectively than microfracture with large-diameter awls,16 we prefer making small-diameter holes when establishing the maximum number of holes possible. As it is important to make a perpendicular hole, not a scratch, we use an XL Microfracture Pick (Smith & Nephew) 90° curve, which is suitable for creating a vertical entry point. The 60° curved awl is then used to further deepen the hole. Creation and stability of the marrow clot are ensured by shutting down the infusion pump device and verifying that blood and marrow elements are released from the microfractures.
Capsule Management
The increase in hip arthroscopies performed worldwide has generated interest in proper capsular management and development of iatrogenic microinstability.17 Hip capsulotomy is routinely performed for adequate visualization of the intra-articular compartment. Standard anterosuperior interportal capsulotomy for hip arthroscopic surgery (12 to 3 o’clock) sacrifices the integrity of the iliofemoral ligament (ligament of Bigelow),18 which provides rotational stability. Failure to restore the anatomical and biomechanical properties of the iliofemoral ligament after arthroscopic surgery increases the likelihood of postoperative microinstability or gross instability,19 which can lead to persistent pain and/or sense of an unstable joint, in addition to accelerated cartilage wear.
Capsulotomies are useful in obtaining adequate intraoperative exposure of the central and peripheral compartments. In the past, little attention was given to capsular closure on completion of the procedure. However, concern about postoperative instability from capsular laxity or deficiency made the introduction of capsular repair techniques necessary. Although deciding between capsular closure and plication remains debatable, we routinely perform capsular closure with a Quebec City slider knot.20 Mindful management of the capsule throughout the procedure is important in avoiding irreversible capsular damage, which would complicate capsular closure. Mindful management involves leaving a proximal leaflet of at least 1 cm during the capsulotomy, avoiding capsular thinning during shaver use, and using a cannula to prevent soft-tissue bridging.
Recent evidence suggests that capsule repair restores near native hip joint stability.17 In addition to capsular shift or capsulorrhaphy, 2 to 6 sutures have been used for capsular closure or plication after an interportal or T capsulotomy. Chahla and colleagues21 reported that 2- and 3-suture constructs produced comparable biomechanical failure torques when external rotation forces were applied to conventional hip capsulotomy on cadavers. Three-suture constructs were significantly stronger than 1-suture constructs, but there was no significant difference between 2- and 3-suture constructs. All constructs failed at about 36° of external rotation. Therefore, restricted external rotation is recommended for 3 weeks after surgery.
In one study, 35% of revision hip arthroscopy patients had undiagnosed hip instability from iatrogenic injury,22 which can lead to labral and chondral injury.17 Capsular reconstruction is recommended in cases of symptomatic capsular deficiency; capsular deficiency caused by adhesion removal; and pain and range-of-motion limitation caused by capsular adhesions. However, indications need to be further established. We have performed capsular reconstruction with ITB allograft23 (Figure 5).
