Predictors of Achieving the Maximal Outcome Improvement Threshold for Willingness to Undergo Revision Hip Arthroscopy.

Background: The maximal outcome improvement threshold for willingness to undergo revision hip arthroscopy (MOWT) has not been defined yet.

Purpose: To determine the percentage MOWT in patients who underwent revision hip arthroscopy and to identify predictors of achieving the MOWT.

Study Design: Case-control study; Level of evidence, 3.

Methods: An anchor question was provided to patients who underwent revision hip arthroscopy between April 2008 and June 2020 who returned for follow-up between August 2019 and June 2021 at one institution. Patients were included if they underwent revision hip arthroscopy, had answered the anchor question, and had baseline and postoperative minimum 1-year follow-up scores for the modified Harris Hip Score (mHHS), Nonarthritic Hip Score (NAHS), and the visual analog scale (VAS) for pain. Exclusion criteria were Tönnis grade >1, hip dysplasia, previous hip conditions, or unwillingness to participate. Receiver operating characteristic analysis was used to determine the MOWT. Multivariate logistic regression was used to determine intraoperative predictors of achieving the MOWT.

Results: In total, 153 patients (163 hips) were included, with 117 female hips (71.8%), a mean patient age of 34.3 ± 12.4 years, and an average follow-up time of 61.6 ± 42.7 months. It was determined that 77.3% of the patients reported that they would choose to undergo the revision hip arthroscopy again. The MOWT for the mHHS, NAHS, and VAS was 43.1%, 53%, and 33.4%, respectively. The probability of choosing to undergo revision surgery if the MOWT was achieved was 77.5%, 77.6%, and 79.2%, for the mHHS, NAHS, and VAS, respectively. Patients with residual cam-type morphology, which was addressed during the revision, were 2.3 times more likely to achieve the MOWT for the VAS ( = .014).

Conclusion: Patients who improved 43.1%, 53%, and 33.4% of their MOWT for the mHHS, NAHS, and VAS, respectively, were likely to be willing to undergo revision hip arthroscopy again. Moreover, the presence of residual cam-type femoroacetabular impingement morphology before their revision surgery was identified as a predictor to achieve the MOWT for the VAS.