AGE, BMI, AND LATERAL JOINT SPACE WIDTH NEGATIVELY INFLUENCE OUTCOMES AT 12-YEAR FOLLOW-UP OF HIP ARTHROSCOPY FOR FEMOROACETABULAR IMPINGEMENT

Arthroscopic treatment of femoroacetabular impingement (FAI) has grown in popularity since the early 2000s when it was first described. Given this, the mid to long-term outcomes of patients receiving this procedure remains unclear, with only a few mid-term follow-up studies published. Therefore, the aim of this study was to define the outcomes of patients undergoing hip arthroscopy for FAI at a follow-up of 9 to 16 years and to determine the risk factors for failure. The Non-Arthritic Hip Score (NAHS) as well as a radiological evaluation were completed preoperatively and at mid-term follow-up. Participants were divided into two groups according to their clinical evolution after mid-term follow-up. The success group (S) consisted of patients whose NAHS scores at the final follow-up was above the established patient acceptable symptom state (PASS) threshold of 81.9, whereas patients who underwent a second surgical intervention and/or did not reach the PASS threshold at final follow-up were assigned to the failure group (F). These groups were compared to identify preoperative differences in demographic, pathological, and surgical factors. Labral ossification lateral projection length was measured on pelvic anteroposterior view from the lateral edge of the acetabulum to the most lateral point of the ossification. Chi-Squared or Fisher tests were used for dichotomous variables and Student-T or Wilcoxon tests for continuous variables. Multivariate logistic regression was performed by including variables with P < 0.1 in the bivariate analysis. Amongst 118 eligible hips, 95 were included and 23 were lost to follow-up (80.5% follow-up). The mean age at surgery was 28.5 years (range, 16-40) and 20 patients had bilateral, staged procedures (26.7%). At a mean follow-up of 12.1 years (range, 9.2 to 16.0), 9 hips required total hip arthroplasty (THA) (9.5%), 5 required revision hip arthroscopy (RHA) (5.3%), 29 did not achieve the NAHS score PASS threshold (30.5%) whereas 52 achieved it (54.7%). The mean NAHS score was 82.4 at final follow-up compared to 66.9 preoperatively (mean difference = 15.5, p < 0.001). Higher Body-mass index (BMI) (mean, 23.0 vs 24.9; P = 0.030), older age (mean, 27.2 vs 30.0; P = 0.035) and inferior preoperative lateral joint space width (JSW) (mean, 4.4 vs 3.9; P = 0.019) were associated with inferior prognosis (P < .05). At the postoperative radiological analysis, osteoarthritis progression was observed in 69.2% of the failure group and in only 34.8% of the healthier group (P = 0.082). Labral ossification was observed in 78.3% of all patients and its lateral projection length was statistically associated with failure (P = 0.015). At a mean 12-year follow-up, patients undergoing hip arthroscopy for femoroacetabular impingement maintained a significant clinical improvement with only a 9.5% THA conversion rate. Increased BMI, older age and inferior preoperative lateral joint space width were significant negative prognostic factors. Postoperative degenerative changes were highly prevalent and demonstrated association with failure.