Microfracture for grade IV chondral lesions of the hip (SS‐89)

Articular lesions are the second most common pathology encountered among patients undergoing hip arthroscopy. It is postulated that the microfracture principle may have application in the hip. This study reports the results of this technique in a series of hip arthroscopy patients. Methods: All patients undergoing arthroscopy are prospectively assessed. Twenty-one patients were identified that had undergone microfracture and had achieved a minimum two year follow-up. The indications for the procedure were a well circumscribed Grade IV articular lesion with intact subchondral bone and healthy surrounding cartilage, and ability of the patient to participate in the 3 month structured postoperative rehabilitation protocol. This protocol included 10 weeks of protected weight bearing, emphasizing range of motion and low resistance exercises, followed by transition to a weight bearing program and gradual resumption of normal activities. Results: There was 100% follow-up at an average of 32.6 months. The average age was 35.0 years. Work up included radiographs in all cases, 17 MRIs, 8 intra-articular injections, 2 MRAs, 2 CT scans, and 2 bone scans. Radiographs were normal in 13 cases (62%) and revealed evidence of degenerative changes in 8 cases (38%). MRI or MRA revealed evidence of articular pathology in only 4 cases (19%) and was inadequate at grading the lesion. Indirect findings of articular damage was evidenced by subchondral cyst formation (4 cases), edema or stress reaction of the subchondral bone (4 cases), and effusion (3 cases). At arthroscopy, the Grade IV lesion addressed was on the acetabular surface in 19 cases, the femoral surface in 1 case, and both surfaces in 1 case. Among the 19 acetabular lesions, 17 had associated labral pathology, 3 had accompanying Grade III lesions of the femoral head, and there were 3 degenerate ruptures of the ligamentum teres. The mean dimensions of the Grade 4 lesions were 12.2mm2 (range 6–17.5mm2). The mean improvement was 23.9 points (preoperative 51.4; postoperative 75.2). Quantitative improvement was maintained in 18 patients (86%). There was no correlation with radiographic findings, other imaging findings, associated pathology, dimensions of the lesions, or CE angle. There were no complications and all patients demonstrated compliance with the rehabilitation process. Discussion and Conclusions: Radiographs were poorly reflective of Grade IV articular lesions amenable to microfracture. Other investigative studies were unreliable at detecting these lesions and are incapable of assessing the necessary parameters for selecting the microfracture method. The decision to perform microfracture is based on the arthroscopic appearance of the defect. Thus, the surgeon must maintain an index of suspicion and include the ramifications of the postoperative rehabilitation in the preoperative discussion. The results are encouraging, although some patients did poorly despite proper selection for the procedure and compliance with the rehabilitation. In absence of controls, it is impossible to compare these results to the natural history of this process; but it is speculated that, when successful, this technique may positively influence the expected progression of these Grade IV lesions.