Reliability and validity of self-paced walking time measures for knee osteoarthritis.

This study assessed the reliability and validity of self-paced walking time as an outcome measure for osteoarthritis (OA) of the knee. The 13-m timed walking tests were carried out twice on two separate occasions for 15 patients using photocells. Validity was examined by comparing the walking time data with results of other methodologies for evaluating osteoarthritic gait. As indicated by intra- and inter-day intraclass correlation coefficients of 0.97 and 0.88 the gait measurements were reliable. The measurements also compared favorably with a validated subjective functional index for knee OA (P < 0.01). The findings suggest that measurements of self-paced walking time can provide both reliable and valid data for evaluating functional performance in this patient population.