Responsiveness of patient reported outcome measures in total joint arthroplasty patients.

UNLABELLED: This study reports the responsiveness to change and minimal clinically important difference (MCID) of three patient reported outcome measures following total hip arthroplasty (THA) and total knee arthroplasty (TKA). Patient-reported outcome measures were collected preoperatively and 3 months postoperatively for 391 patients enrolled in the California Joint Replacement Registry. Effect size, standardized response means, and MCID were calculated for each measure. The WOMAC and the SF12v2 physical component summary (PCS) score were the most responsive to perioperative changes. The MCID was 4.97 for the SF12v2 PCS and 10.21 for the WOMAC. THA patients were more likely to exhibit improvements above the MCID than TKA patients. The WOMAC and SF12v2 PCS are useful to measure health status changes in TJA patients. LEVEL OF EVIDENCE: Prognostic Level II.