Failure to Achieve Threshold Scores on Patient-Reported Outcome Measures Within 1 Year Has a Predictive Risk of Subsequent Hip Surgery Within 5 Years of Primary Hip Arthroscopy: A Case-Control Study

Abstract

Background: Research has identified factors that influence achievement rates of threshold scores on patient-reported outcome measures (PROMs) after hip arthroscopy. However, little data exist on whether failure to achieve a threshold score (minimal clinically important difference [MCID] or substantial clinical benefit [SCB]) in the short term after hip arthroscopy predicts the risk of future hip surgery. Purpose/Hypothesis: The purpose of this study was to determine if failure to achieve the MCID or SCB on PROMs within 1 year of hip arthroscopy can be considered a risk factor for repeat surgery within 5 years of primary hip arthroscopy. It was hypothesized that failure to achieve threshold scores would increase the risk of subsequent hip surgery. Study Design: Case-control study; Level of evidence, 3. Methods: A retrospective review of prospectively collected data was completed. Four PROMs were collected preoperatively and within 1 year of hip arthroscopy: modified Harris Hip Score, Hip Outcome Score–Activities of Daily Living, Hip Outcome Score–Sports, and the 33-Item International Hip Outcome Tool. Results: Two cohorts were formed: (1) a study cohort (n = 88) composed of patients who underwent repeat hip surgery within 5 years of hip arthroscopy and (2) a control cohort (n = 288) composed of patients who did not require repeat hip surgery. The study cohort had significantly ( P < .001) lower scores on all postoperative PROMs, and a significantly ( P < .001) smaller percentage of the study cohort met the MCID and SCB. Multivariable regression analysis demonstrated that not achieving the MCID or SCB on each of the PROMs is an independent risk factor for repeat hip surgery. For every PROM in which a patient failed to achieve the MCID, the odds of subsequent surgery increased by 1.68 (95% CI, 1.42-1.98; P < .001). For every PROM in which a patient failed to achieve the SCB, the odds of subsequent surgery increased by 1.63 (95% CI, 1.35-1.97; P < .001). Conclusion: Failure to meet threshold scores on PROMs after hip arthroscopy was an independent risk factor for subsequent hip surgery. This study establishes a novel utility of PROMs and confirms the importance of these metrics in the orthopaedic literature.