Articular cartilage changes in avascular necrosis: an arthroscopic evaluation.

Treatment methods for osteonecrosis (avascular necrosis) are wide and varied. When untreated, progression of the disease is common and may dictate femoral head replacement. However, before femoral head collapse, some patients have mechanical joint symptoms (locking, buckling, clicking) that are unaddressed by femoral head drilling alone. Radiographic examinations in these patients usually are nondiagnostic. Patients with these clinical criteria were evaluated arthroscopically. Between 1993 and 2000, seven patients were identified with known documented or radiographic diagnosis of avascular necrosis who had hip arthroscopy. Each patient's preoperative history, physical examination, plain radiographs, magnetic resonance imaging scans, and operative notes were reviewed from a prospectively-derived database. The duration and onset of symptoms were identified carefully. Case histories are presented on five of these patients. Articular cartilage changes were recorded and correlated to the preoperative radiologic studies. Hip arthroscopy is a minimally invasive, highly effective, joint-preserving surgery in the young patient with mechanical symptoms (locking, catching, buckling) and early avascular necrosis. Treatable lesions include loose bodies, synovitis, chondral flaps, and labral tears. In addition, accurate staging can be accomplished through direct observation.