Global Acetabular Retroversion Is Associated with Increased Conversion to Total Hip Arthroscopy after Primary Hip Arthroscopy: A Propensity-Matched Analysis with Minimum 8-Year Follow-up

Objectives: The purpose of the present study was to compare long-term survivorship following primary hip arthroscopy between patients with global acetabular retroversion and a propensity-matched control group. Methods: This retrospective study queried patients > 18 years, with preoperative hip and pelvic radiographs, and minimum 8-year follow-up that underwent hip arthroscopy by a single surgeon for the treatment of symptomatic labral tears secondary to FAI. Patients with global acetabular retroversion, as indicated by the presence of a crossover sign, ischial spine sign, and posterior wall sign on preoperative pelvic radiographs, were propensity-score matched 1:1 by age, sex, body mass index (BMI), and labral treatment (repair versus debridement) to controls. Baseline demographic, radiographic, and intraoperative variables were compared between cohorts. Cox multivariate regression controlling for global retroversion and Tönnis grade was used to assess conversion to THA. Patient-reported outcome measures (PROMs) were compared between cohorts. Results: Overall, 49 patients with global retroversion were 1:1 matched to 49 controls, with mean follow-up of 10.7 ± 2.1 years and 11.1 ± 2.8 years, respectively. There were no significant differences in baseline demographics, radiographic findings, or intraoperative findings between cohorts (P>0.05 for all) ( Table 1; Table 2 ). Unadjusted Kaplan-Meier survival curves analyzed by log-rank test demonstrated a significantly decreased survivorship among patients with global retroversion (68.6%) compared to controls (83.9%) at final follow-up (P=0.036) ( Figure 1 ). Cox multivariable regression controlling for Tönnis grade demonstrated that patients with global retroversion had a significant greater risk of THA conversion (hazard ratio, 3.94; p=0.038). There were no differences in PROMs at final follow-up between cohorts (P>0.05 for all) ( Table 3 ). Conclusions: Patients with global acetabular retroversion had significantly inferior THA-free survivorship at minimum 8-year follow-up relative to matched controls, despite no differences in PROMs at final follow-up for patients who did not undergo THA. These findings suggest that global retroversion by preoperative radiographic assessment may be a useful predictor of long-term failure and that patients should be counseled accordingly.