performance based patient outcome score for active patients following total knee arthroplasty.

OBJECTIVE: The aim of this study was to develop and validate a user friendly performance based knee outcome score for use in active patients undergoing TKA surgery. DESIGN: We prospectively studied a cohort of 50 subjects without any knee symptoms, and 50 patients who underwent TKA for osteoarthritis (OA). The patients were assessed pre- and postoperatively. SF-36 and WOMAC were concurrently administered for comparison. Patients completed seven physical tasks of the finalised outcome instrument which were objectively assessed and scored. RESULTS: The mean functional score was 31.7 in the normal subjects. The mean functional score improved postoperatively from 10.0 to 17.7 (P < 0.001) in the TKA group. Our results confirm that the performance based score has a high test-retest reliability (intra-class correlation coefficient (ICC) of 0.89), internal consistency (Cronbach's alpha 0.84) and construct validity showing expected correlations with relevant components of the WOMAC and SF-36 scores. The responsiveness as measured by the effect size compared favourably with the same relevant components of the SF-36 and WOMAC. CONCLUSIONS: Our performance based knee function score is a reliable dimension specific tool to detect change in musculoskeletal function after TKA. It complements existing self-reported outcome tools in facilitating a comprehensive assessment of patients following TKA.