The relationship between diagnosis and outcome in arthroscopy of the hip.

PURPOSE: The purpose of this study was to compare the results of arthroscopy of the hip for osteonecrosis (ON) with those obtained for other diagnoses by presenting a cohort of patients with diagnosis and symptoms as dependant variables in a consecutive series of 86 cases of hip arthroscopy. TYPE OF STUDY: Retrospective review of outcomes. METHODS: There were 83 patients (86 hips) who underwent arthroscopy. Indications included ON (43%), labral injuries (20%), osteoarthritis (degenerative joint disease, DJD) (10%), Legg-Calvé-Perthes (LCP) disease (10%), and loose bodies (10%). All but 2 patients had had symptoms for at least 6 months. Symptoms were pain (100%), mechanical problems (78%), and loss of motion (56%). Arthroscopy was performed in the supine position, using a standard traction table, 30 degrees and/or 70 degrees arthroscopes, and the anterior and peritrochanteric portals. Data were collected longitudinally, retrospectively reviewed, and statistically analyzed. RESULTS: No complications were seen; 60% of the patients had significant improvement over an average follow-up of 30 months. Better results were with labral tears (91%, P <.003) or LCP disease (89%, P <.05). ON and DJD did worse with only 40% and 44% improvement, respectively. After free-vascularized fibular graft (FVFG), 34% of patients showed improvement at follow-up (P =.003). Eighteen patients (21%) underwent total hip arthroplasty at an average of 8.4 months after arthroscopy. Mechanical symptoms were a significant favorable prognostic factor (P =.0019), with 85% having a good result. Patients with ON and mechanical symptoms had a significantly lower conversion rate to total hip arthroplasty than those with only pain or pain and decreased range of motion (P =.0043). CONCLUSIONS: Arthroscopy of the hip is useful for diagnosis and therapy of loose bodies, labral injuries, focal chondral lesions, or the late sequellae of LCP disease. We conclude that the presence of mechanical symptoms is a favorable prognostic factor for any diagnosis except degenerative arthritis. Furthermore, the identification of mechanical symptoms is a specific indication for arthroscopy in ON before or after FVFG.