EP8.80 Patients with Tönnis Grade 0 and 1 Demonstrate Durable Outcomes at 15-year Follow Up

Abstract

Abstract Background Though osteoarthritis is a known risk factor of decreased outcomes following hip arthroscopy for femoroacetabular impingement syndrome (FAIS), long-term outcomes comparing those with and without mild arthritis have not been defined. Purpose The purpose of this study is to evaluate the effect of Tönnis grade on 15-year patient-reported outcomes, clinically meaningful improvement, and survivorship following hip arthroscopy. Methods Patients undergoing primary hip arthroscopy were stratified by Tönnis grade (0 vs 1). Patients with Tönnis grade 0 were propensity score matched to patients with Tönnis grade 1 arthritis controlling for age, sex, body mass index (BMI), smoking status, labral debridement, capsular closure, lateral center-edge angle (LCEA), and alpha angle (45° view). Outcomes included modified Harris Hip Score (mHHS) and Non-Arthritic Hip Score (NAHS) at baseline and 15 years, as well as change (Δ) scores. Achievement of minimal clinically important difference (MCID; MHHS ≥6.685, NAHS ≥6.08) and patient acceptable symptomatic state (PASS) were calculated. Revision surgery and conversion to total hip arthroplasty (THA) were assessed and compared between groups. Continuous variables were compared using Welch t-tests, and categorical variables with Fisher’s exact tests. Results A total of 55 matched patients were included, 21 with Tönnis grade 1 and 34 with Tönnis grade 0. There were no significant differences in baseline demographics and 15-year PROs between cohorts (mHHS: 88.3 vs 89.2, p = 0.863; NAHS: 86.6 vs 88.0, p = 0.825). Similarly, improvements from baseline were comparable (ΔMHHS: 38.1 vs 36.4, p = 0.847; ΔNAHS: 44.6 vs 41.6, p = 0.643). Rates of patient-acceptable symptom state (PASS) achievement were high among the cohorts (mHHS, p = 0.754; NAHS, p = 0.754). Though the Tönnis grade 1 cohort demonstrated similar achievement of minimally clinically important difference (MCID) for mHHS (p = 0.369), they approached significantly lower rates of achievement for NAHS (p = 0.053). There were no differences in survivorship outcomes, including revision surgery (p = 1.00), conversion to THA (p = 0.300), time to revision (p = 0.780), or time to THA (p = 0.503). Conclusion Patients with Tönnis grade 1 osteoarthritis achieved comparably durable 15-year total outcomes, improvement, and survivorship to those with Tönnis grade 0 following hip arthroscopy for FAIS. While a trend toward lower NAHS MCID achievement was observed in Tönnis 1 patients, this did not reach statistical significance. These findings suggest that mild radiographic osteoarthritis should not be considered a contraindication to hip arthroscopy in appropriately selected patients.