Outcomes of Hip Arthroscopic Surgery in Patients With Tönnis Grade 1 Osteoarthritis at a Minimum 5-Year Follow-up: A Matched-Pair Comparison With a Tönnis Grade 0 Control Group


Background: Studies on midterm outcomes of the arthroscopic treatment of femoroacetabular impingement (FAI) and labral tears with mild osteoarthritis (OA) are limited.

Purpose: To evaluate outcomes of the arthroscopic treatment of FAI and labral tears in patients with mild preoperative OA (Tönnis grade 1) at a minimum 5-year follow-up, and to perform a matched-pair comparison to a control group with Tönnis grade 0.

Study design: Cohort study; Level of evidence, 3.

Methods: Data were prospectively collected on patients who underwent hip arthroscopic surgery between February 2008 and April 2011. Inclusion criteria were arthroscopic treatment for FAI and labral tears and having preoperative patient-reported outcome (PRO) scores, including the modified Harris Hip Score (mHHS), Non-Arthritic Hip Score (NAHS), and Hip Outcome Score-Sports-Specific Subscale (HOS-SSS), and visual analog scale (VAS) scores for pain. Exclusion criteria were workers' compensation claims, preoperative Tönnis grade ≥2, and previous hip conditions (ipsilateral surgery, slipped capital femoral epiphysis, avascular necrosis, and dysplasia). Patients with minimum 5-year outcomes were eligible for matching on a 1:1 ratio (Tönnis grade 0 vs 1) based on age ±5 years, body mass index ±5 kg/m2, sex, labral treatment, and capsular treatment.

Results: Of 356 eligible hips, 292 hips had minimum 5-year outcomes (82%). Eighty-five hips with Tönnis grade 1 were evaluated. At 5-year follow-up, patients with Tönnis grade 1 had significant improvements in all PRO and VAS scores ( P < .0001). The overall satisfaction score was 8.2. The survivorship rate with respect to conversion to total hip arthroplasty for the Tönnis grade 1 group was 69.4% at 5 years, while in the Tönnis grade 0 group, it was 88.4% ( P = .0002). Sixty-two hips with Tönnis grade 0 were matched to 62 hips with Tönnis grade 1. Both groups demonstrated improvements in all PRO and VAS scores from preoperatively to postoperatively ( P < .0001). No significant differences existed between preoperative or postoperative scores or survivorship between the groups.

Conclusion: The arthroscopic treatment of FAI and labral tears in patients with Tönnis grade 1 had good results at 5-year follow-up. After controlling for other variables using a matched-pair comparison, patients with Tönnis grade 1 had similar, durable improvements to those with Tönnis grade 0. While strict surgical indications and appropriate expectations are recommended for patients with mild OA, Tönnis grade 1 alone should not be considered a contraindication to hip arthroscopic surgery.

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