Measured ambulation and self-reported health status following total joint replacement for the osteoarthritic knee

Objective. To quantify the increase in ambulation produced by total knee replacement for osteoarthritis (OA) of the knee and to compare this with questionnaire-derived data. Methods. We compared the measured ambulatory activity and self-reported Nottingham Health Profile (NHP) data of 19 subjects with OA of the knee before and after total knee replacement (TKR). Results. Subjects were considerably restricted in their measured activity before operation compared with subjects with less severe disease. At 6 months the activity had increased by an average of 79% (P=0.02). The pain scale of the NHP had significantly improved at 3 months, as had the mobility scale. Between 3 and 6 months, however, at the same time the measured activity was increasing, self-reported mobility declined. Conclusions. Replacement of a knee for OA is an effective way of improving ambulation. At 6 months the average increase amounted to 79%. Self-reported mobility did not correlate with mobility measured objectively.