Achievement of One-Year MCID Varies with Preoperative Function of Patients Undergoing Total Hip Arthroplasty

Abstract

The minimum clinically important difference (MCID) of an orthopaedic outcome measure is commonly used to assess treatment success including for patients undergoing total hip arthroplasty (THA). Various patient factors may contribute to MCID values in patients undergoing THA. The purpose of this study was to calculate the 1-year MCID for the Hip Disability and Osteoarthritis Outcome Score for Joint Replacement (HOOS-JR) based on patient factors and evaluate if there were any differences between each cohort's MCID.A patient-reported outcome measure (PROM) database was reviewed for patients undergoing THA from 2017 to 2018. Patients were included that underwent primary THA and completed baseline and 1-year follow-up for Patient-Reported Outcome Measurement Information System 10-item global health form (PROMIS10) and HOOS-JR surveys. MCID was calculated using the distribution method and an anchor-based method that used the PROMIS10 Physical Health item. Differences in MCID were assessed between patient cohorts stratified by preoperative characteristics.For the 523 patients that underwent THA, the average 1-year HOOS-JR MCID values were 33.9 ± 16.3 (men), 37.0 ± 13.9 (women), 38.1 ± 17.1 (diagnosis of mental health), and 35.0 ± 14.6 (no diagnosis). MCID values were not significantly different between groups according to sex (p = 0.186) or mental health status (p = 0.302). MCID value did not correlate with body mass index (β = –0.126). MCID achievement had a notable inverse relationship with preoperative HOOS-JR.This study demonstrated that preoperative function of patients undergoing THA affects the ability to achieve HOOS-JR 1-year MCID. Future investigation is necessary to clarify which patient factors may affect MCID.