Summary

Os acetabuli were not found to be associated with differential 2-year functional outcomes or rates of achieving clinically meaningful improvements.

Abstract

Introduction

To investigate whether os acetabuli influence 2-year functional outcomes following arthroscopic acetabular labral repair.

Methods

Prospectively collected data from patients undergoing primary hip arthroscopy by a single, fellowship-trained sports medicine surgeon were retrospectively reviewed. Inclusion criteria were age ≥18 years and completion of patient-reported outcome measures (PROMs) preoperatively and at 3-, 6-, 12-, and 24-month follow-up. Exclusion criteria were labral debridement, hip dysplasia, advanced hip osteoarthritis (Tönnis grade >1), or previous surgery on the ipsilateral hip. Patients were divided into cohorts based on the presence of an os acetabulum identified on preoperative anteroposterior (AP) radiographs. Primary outcomes collected included the International Hip Outcome Tool (iHOT-33) and modified Harris Hip Score (mHHS). Secondary outcomes were the Hip Outcome Score-Activities of Daily Living, Hip Outcome Score-Sports Subscale, Non-Arthritic Hip Score, and visual analog pain scale. Inter-cohort outcomes were compared using linear mixed-effects modeling and Fisher’s exact tests. Nonlinear improvement trajectories were accounted for by sensitivity analyses.

Results

193 hips (49.2% female; mean±SD age, 35.9±11.0) were included in the final analyses. Of these, 25 (13.0%) had an os acetabulum. No significant differences in iHOT-33 (weighted difference: 0.09; 95% CI: -6.81, 6.98; p=0.98) or mHHS scores (weighted difference: 2.93; 95% CI: -2.13, 7.98; p=0.26) were found between patients with versus without os acetabuli across the 2-year follow-up period. Additionally, there were no significant differences in rates of achieving clinically meaningful outcomes (p>0.05 for all), revision arthroscopy (p=.342), heterotopic ossification formation (p>.999), or conversion to total hip arthroplasty (p>.999). These results were upheld across sensitivity analyses.

Conclusions

Os acetabuli were not found to be associated with differential 2-year functional outcomes or rates of achieving clinically meaningful improvements. Thus, appropriately managed os acetabuli are not a contraindication to arthroscopic labral repair.