Treatment of femoro-acetabular impingement with surgical dislocation and debridement in young adults

Background: Femoro-acetabular impingement has been associated with acetabular labral and/or articular cartilage damage that may ultimately result in osteoarthritis of the hip. Surgical treatment of femoro-acetabular impingement is directed at restoring a more normal femoral head-neck offset to alleviate femoral abutment against the acetabular rim and treating associated labral and articular cartilage damage. Methods: Thirty hips with femoro-acetabular impingement (in twenty-nine patients) underwent debridement through a greater trochanteric flip osteotomy and anterior dislocation of the femoral head. There were sixteen male patients and thirteen female patients with a mean age of thirty-one years. Cam (femoral based) impingement was noted in fourteen hips; pincer (acetabular based) impingement, in one hip; and combined cam and pincer impingement, in fifteen hips. The mean duration of clinical and radiographic follow-up was thirty-two months. All patients were followed according to a prospective protocol, with Harris hip scores and plain radiographs obtained preoperatively and at six months, one year, and annually for a minimum of two years. Results: The mean Harris hip score improved from 70 points preoperatively to 87 points at the time of final follow-up (p < 0.0001). Osteonecrosis did not develop in any hip, and there were no trochanteric nonunions. In eighteen hips, severe damage of the acetabular articular cartilage that had not been appreciated on preoperative plain radiographs or magnetic resonance arthrography was noted on arthrotomy. Eight of these eighteen hips subsequently had radiographic evidence of progression of the osteoarthritis, and four of the eight hips required or were expected to soon require conversion to a total hip arthroplasty to treat progressive pain. Conclusions: At the time of early follow-up, we found that surgical dislocation and debridement of the hip for the treatment of femoro-acetabular impingement in hips without substantial damage to the articular cartilage can reduce pain and improve function. This procedure has a low rate of complications. Radiographic signs of progression of osteoarthritis and clinical failure requiring conversion to a total hip arthroplasty were seen only in patients with severe damage to the acetabular articular cartilage, a finding that emphasizes the need for better imaging methods to assess the extent of damage to the acetabular articular cartilage in patients with this disorder.