Paper 46: Modern Hip Arthroscopy for FAIS Delays the Natural History of Osteoarthritis in a Fourth of Patients: A 12-Year Follow-Up Analysis

Abstract

Objectives: Little is known about the impact of modern hip arthroscopy on the natural history of femoroacetabular impingement syndrome (FAIS) with respect to joint preservation. The purpose of this investigation was to (1) characterize the natural history of FAIS and (2) understand the impact of modern hip arthroscopy by radiographically comparing the hips of patients who underwent only unilateral primary hip arthroscopy with a minimum follow-up of ten years. Methods: Between 2010-2012, 619 consecutive patients were reviewed from the practice of a single fellowship-trained hip arthroscopist. Inclusion criteria were FAIS, primary unilateral hip arthroscopy (labral repair, femoroplasty, capsular closure), and minimum ten-year follow-up. The preoperative and minimum ten-year postoperative radiographs of patients were evaluated at each timepoint. Both operative and nonoperative hips were graded using the Tönnis classification or the presence of hip arthroplasty by two independent reviewers. Subgroup analyses were performed. Results: A total of 200 hips from 100 patients were available with 74% follow-up at a mean of 12.0 years were evaluated. The nonoperative hip advanced to a worse Tönnis grade in 48% (48/100) of cases compared to 28% (28/100) among operative hips (Table 1). At follow-up, Tönnis grades between hips were equal in 70% (70/100) of the cases, the operative hip had a better grade 25% (25/100) of the time, and the nonoperative hip had a better grade 5% (5/100) of the time (Table 2). Modern hip arthroscopy conferred a relative risk reduction of 42% in osteoarthritis progression. Borderline dysplasia, age, preoperative Tönnis grade, and alpha angle > 65° were key risk factors in the radiographic progression of osteoarthritis. Conclusions: While the majority of patients (70%) undergoing hip arthroscopy for FAIS did not experience differences between operative and nonoperative hips in terms of the radiographic progression of osteoarthritis, the natural history was favorably altered in a quarter of patients after arthroscopic correction (Figure 1). Modern hip arthroscopy indications and techniques represent a valid joint preservation procedure conferring a relative risk reduction of 42% in the progression of osteoarthritis. Mixed patterns of impingement and instability that underwent arthroscopy were the fastest to degenerate.