The THA-10 Score for Predicting Conversion to Total Hip Arthroplasty After Contemporary Hip Arthroscopy for Femoroacetabular Impingement Syndrome at a Minimum 10-Year Follow-up.

Abstract

Previous studies have identified predictors of total hip arthroplasty (THA) conversion after hip arthroscopy (HA) for femoroacetabular impingement syndrome (FAIS) at short- to midterm follow-up, yet no studies to the authors' knowledge have established a scoring system for predicting THA conversion at a minimum 10-year follow-up. To create a scoring system to predict 10-year THA conversion after contemporary HA for FAIS. Case-control study; Level of evidence, 3. Data were prospectively collected from patients undergoing primary contemporary HA for FAIS, including labral repair, osteoplasty of FAIS deformity, and capsular repair, between January 2012 and October 2013, with a minimum 10-year follow-up. Patients who underwent THA conversion were compared with patients who achieved 10-year THA-free survivorship. Significant predictors of THA conversion were identified, and predictor weights were assigned to create the THA-10 score. The score was applied to the cohort, and its clinical utility was evaluated. The threshold score with the greatest sensitivity and specificity for predicting 10-year THA conversion was identified. In total, 280 patients were included; 21 (7.5%) underwent THA conversion by the 10-year follow-up. Patients who underwent THA conversion were of older age (45.4 ± 11.3 vs 33.2 ± 12.1 years; <i>P</i> < .001), had a greater body mass index (28.0 ± 5.2 vs 24.8 ± 4.7 kg/m²; <i>P</i> = .011), and had a greater prevalence of Tönnis grade 1 osteoarthritis (42.9% vs 14.3%; <i>P</i> = .003) and high-grade acetabular (61.9% vs 12.7%; <i>P</i> < .001) and femoral head (33.3% vs 7.3%; <i>P</i> < .001) chondral defects compared with THA-free survivors. After variable weighting, the THA-10 score was established as 1 point for body mass index ≥25 kg/m², 1 point for Tönnis grade 1, 2 points for age ≥47 years, and 3 points for high-grade defects of the acetabulum or femoral head. The THA-10 score was found to have clinically significant diagnostic value with an area under the receiver operating characteristic curve of 0.823. Patients scoring ≥4 points were 13.2 times more likely to undergo THA conversion (95% CI, 5.0-35.1; <i>P</i> < .001). This study created the THA-10 score and showed it to have clinically significant diagnostic utility in predicting 10-year THA conversion after HA for FAIS. Patients scoring ≥4 points were 13.2 times more likely to undergo THA conversion.