Normative Functional Outcomes as a New Outcome Assessment Tool Following Hip Procedures

Patient-reported outcome measures play an important role in evaluating the functional outcome of surgical and nonsurgical treatments of the hip joint. One thousand healthy volunteers completed the modified Harris hip score, the University of California, Los Angeles score, the Hip Osteoarthritis Outcome Score, and the Western Ontario and McMaster Universities Osteoarthritis Index score. Between September 2010 and December 2015, a total of 127 periacetabular osteotomies were performed in 111 patients with symptomatic developmental dysplasia of the hip. Forty-two of these patients (10 male and 32 female) met inclusion criteria. Mean follow-up was 32 months (range, 13-59 months). Pre- and postoperative radiographic analysis of the lateral center-edge angle and the acetabular index was conducted in all cases with a proper pelvic anteroposterior radiograph. The patients completed the modified Harris hip score, the University of California, Los Angeles score, the Hip Osteoarthritis Outcome Score, and the Western Ontario and McMaster Universities Osteoarthritis Index score. The authors investigated the influence of various confounding variables to (1) obtain recommendations when outcome scores are being compared between 2 cohorts and (2) define a normative reference level of "hip-healthy" functionality. This normative level of functionality was used as a target level of functionality following a hip procedure such as periacetabular osteotomy. All functional outcome scores had significantly improved 1 year after periacetabular osteotomy; thus, patients were much better than preoperatively. However, only 55% achieved the 95% functionality of the normative population based on modified Harris hip score and University of California, Los Angeles score. The results were worse for the Hip Osteoarthritis Outcome Score subscales. This approach places the results of surgical procedures in a different but potentially more realistic perspective in terms of expectations and goals. [Orthopedics. 2018; 41(5):e663-e670.].