FP15.8 Long-Term Outcomes of Patients with Tönnis Grade 1 Osteoarthritis Undergoing Hip Arthroscopy: A Matched-Pair Comparison with a Tönnis Grade 0 Control Group

Abstract ICLB15 - The Preservation Scorecard: Fundamentals of Tracking Outcomes and Standardizing Recovery, Session Room 12 (BMCC Level 3), October 9, 2026, 14:00 - 16:00 Background Limited research exists on long-term outcomes following arthroscopic treatment for femoroacetabular impingement (FAI) and labral tears in patients with mild osteoarthritis (OA). This study evaluates 10-year outcomes of arthroscopic treatment in patients with preoperative Tönnis grade 1 OA compared with a matched cohort of Tönnis grade 0 patients. Methods A retrospective review was conducted on patients who underwent hip arthroscopy between February 2008 and April 2014. Patients with preoperative Tönnis grade 1 OA were matched 1:1 with Tönnis grade 0 controls based on age, sex, BMI, labral and capsular treatment, acetabular Outerbridge classification, and follow-up duration. Inclusion criteria required a minimum 10-year follow-up with patient-reported outcome (PRO) scores, including the Modified Harris Hip Score (mHHS), Non-Arthritic Hip Score (NAHS), Hip Outcome Score–Sports-Specific Subscale (HOS-SSS), and Visual Analog Scale (VAS). Exclusion criteria included prior ipsilateral hip surgery, hip conditions (fractures, slipped capital femoral epiphysis, avascular necrosis, dysplasia with lateral center-edge angle <18°), or worker’s compensation claims. Results Of 217 eligible hips, 174 had a minimum 10-year follow-up (80%) and were matched to 174 control hips. Both groups showed significant improvements in all PROs (p < 0.01). There were no consistent differences in clinically relevant outcomes, including rates of achieving the MCID and PASS. Conversion to total hip arthroplasty (THA) occurred more frequently in the Tönnis 1 group (30.4%) than in the Tönnis 0 group (24.1%), though this difference was not statistically significant (p = 0.18). Rates of secondary arthroscopy were similar between groups (8.6% vs. 9.7%). In a sub-analysis limited to patients treated with modern surgical techniques—including labral repair/reconstruction and capsular closure—there were no significant differences in any PRO, MCID, PASS, or secondary surgery rates between Tönnis grade 1 and 0 patients. Conclusion Hip arthroscopy provides sustained functional benefits and pain relief in patients with Tönnis grade 1 OA, with outcomes comparable to those of Tönnis grade 0 patients. Despite a higher conversion rate to THA, patients with mild OA can achieve substantial long-term improvements, supporting the role of hip arthroscopy as a viable treatment option.