Hip arthroscopy for FAI: Predictors of patient satisfaction and conversion to total hip arthroplasty 5 to 7 years following arthroscopy

Abstract

Objectives: Hip arthroscopy is treatment method for patients with symptomatic femoroacetabular impingement (FAI). It is unclear what factors are associated with mid-term success. The purpose of this study is to report the clinical outcomes and the predictors of successful outcome at a minimum 5 years post-operatively. Methods: Between March 2005 and September 2006, 646 consecutive hip arthroscopies were performed. This study was IRB approved. Patients were included who underwent arthroscopic treatment of symptomatic FAI and chondrolabral dysfunction with radiographic and physical examination findings consistent with FAI. Exclusion criteria included patients < 18 years of age, professional athletes, labral reconstruction, Legg-Calve-Perthes disease, and those with underlying hip disease such as pigmented villonodular synovitis or synovial chondromatosis. All data were prospectively collected and retrospectively reviewed, including physical exam findings, radiographic measurements (alpha angle, the presence of a crossover sign or acetabular dysplasia, and joint space), re-operations or complications, and conversion to THA. Patients were evaluated pre- and post-operatively with a prospective subjective questionnaire. Primary outcome measure included the modified Harris Hip Score (MHHS), and secondary outcome measures included the Western Ontario and McMaster Universities Arthritis Index (WOMAC), Tegner activity scale, patient satisfaction, and conversion to THA. Results: Twenty-four patients were deceased or refused to participate at follow-up, and 284 patients(293 hips) met the inclusion criteria. The average age was 42 years(range, 18 to 77) and there were 140 females and 144 males. Sixty-eight hips (68 patients) required a total hip arthroplasty (THA) (24%). The average age of the THA group was 52 years (range, 32 to 77), with 60 patients (88%) over 40 years of age at the time of arthroscopy. There were 22 females (32%) and 46 males (68%). The average time to THA was 34.6 months post-operatively (range, 7 months to 5 years) and the average pre-operative MHHS was 58 (range, 24 to 100). Of the remaining 216 patients (225 hips), 171 patients (79%, or 178 hips) were available for follow up at a minimum of 5 years. The average follow-up was 6.6 years (range, 5 to 7.2). The MHHS improved from 61 to 80(p<0.001). The average WOMAC at follow-up was 9.0 and the median Tegner activity scale was 4.0. The median patient satisfaction with outcome was 9 (range, 1 to 10). There was no difference in the MHHS between patients who underwent labral debridement or labral repair(p=0.1). The significant multivariate predictors of increased post-operative patient satisfaction at follow-up were higher modified Harris Hip Scores (p=0.003) and not having a microfracture performed(p=0.015)(r2=0.2). Logistic regression modeling identified 2mm or less of joint space (P<0.0001, odds ratio=11.7, 95% CI: 3.6 to 38.1), hip requiring microfracure (o<0.0001, odds ratio=8.6, 95% CI:30. to 26.6) and age at surgery (p<0.0001) as significant independent, multivariate risk factors for conversion to THA. Conclusion: Hip arthroscopy for FAI and chondrolabral dysfunction results in a significant improvement in outcome measures with high patient satisfaction. Predictors of conversion to THA were age, 2mm or less of joint space, and having a microfracture. These results are from early generation hip arthroscopies and these predictors may be managed differently in current practice.