Comparing Methods to Determine the Minimal Clinically Important Differences in Patient-Reported Outcome Measures for Veterans Undergoing Elective Total Hip or Knee Arthroplasty in Veterans Health Administration Hospitals.

Importance: The minimal clinically important difference (MCID) in a patient-reported outcome measure (PROM) is the smallest change that patients perceive as beneficial. Accurate MCIDs are required when PROMs are used to evaluate the value of surgical interventions.

Objective: To use well-defined distribution-based and anchor-based methods to calculate MCIDs in the Hip Disability and Osteoarthritis Outcome Score (HOOS) and in the Knee Injury and Osteoarthritis Outcome Score (KOOS) for veterans undergoing primary total hip arthroplasty or total knee arthroplasty.