Arthroscopic surgery for femoroacetabular impingement has limited effect in patients with Tönnis grade-2 at 4-year follow-up.

Introduction: This study evaluated intraoperative findings and outcomes in Tönnis grade-2 patients after hip arthroscopy and compared these results with patients with Tönnis grade-0 and grade-1.

Materials And Methods: Retrospective cohort study of patients undergoing hip arthroscopy between January 2013 and December 2017. Patients were divided into either Tönnis grade-2, grade-1, and grade-0 osteoarthritis groups. Labral and chondral status were evaluated. Radiographic analysis, modified Harris hip score (mHHS), a self-administered Hip Outcome Score (HOS) questionnaire, with activity of daily living (ADL) and sports subscale (SSS), and a self-administered short version of the International Hip Outcome Tool (IHOT-12) were assessed at 6, 12 months, and then yearly. Clinical meaningful outcomes were measured with the minimal clinical important difference (MCID), patient acceptable symptom state (PASS), and substantial clinical benefit (SCB) for mHHS, HOS-ADL and HOS-SSS, and IHOT-12.

Results: A total of 264 hip arthroscopic procedures met the inclusion criteria. There were 38 patients Tönnis grade-2, 91 patients Tönnis grade-1, and 135 patients Tönnis grade-0. Mean follow-up was 48.7 months in Tönnis grade-2 group, 48.6 months in Tönnis grade-0 group, and 48.1 months in Tönnis grade-1 group. Tönnis grade-2 patients had more extensive rim chondral damage, and a higher rate of labral debridement was performed in this group. There were no statistically significant differences in preoperative PROs among the groups. Tönnis grade-2 group had statistically significant improvement in mHHS, but not in HOS-AVD, HOS-SSS and IHOT-12. Between T1 and T2 groups there were no statistically significant differences in outcomes. Lower significant percentage values of Tönnis grade-2 patients achieved MCID, PASS, and SCB threshold.

Conclusion: Improvements in PROs and rates of achieving clinical meaningful outcomes were limited for patients with Tönnis grade-2 after HA at 4-year follow-up. The outcomes of the Tönnis grade-2 cohort deteriorate over mid-term follow-up. Our results could be used in orthopedic practice to inform patients about the limited role of hip arthroscopy as a joint preservation procedure in these selected patients.

Level Of Evidence: Cohort study, level 3.