Sequential changes in lower extremity function after total knee arthroplasty

Abstract Background: The effectiveness of total knee arthroplasty for recovering ambulation and balance function has not been investigated in detail. The present study aimed to measure functional changes in the lower limb before and after TKA by measuring ambulation function with the 3 meters Timed Up and Go test and balance function using one-leg standing time.Methods: The study included 137 patients (116 women and 21 men) with osteoarthritis of the knee who underwent primary total knee arthroplasty. The mean age of the patients was 74.4 years. The mean postoperative hospital stay for rehabilitation was 23.9 days. The Timed Up and Go test and standing time were performed preoperatively, 2 weeks postoperatively, at discharge, and 3, 6, and 12 months postoperatively. These results from these 6 measurements were also compared using one-way analysis of variance.　We also separated the patients into 3 groups by the length of hospital stay: 3 weeks or less (early discharge group), 3 to 4 weeks (standard discharge group), and over 4 weeks (late discharge group). The Timed Up and Go test and standing time among the 3 groups were evaluated at 6 measurement points.Results: Ambulation and balance function were significantly improved at 3 months after surgery. However, ambulation and balance function did not improve further from 3 months to 6 months postoperatively or from 6 months to 1 year postoperatively. Ambulation function in the early and standard discharge group were significantly lower than those in the late discharge group at all measurement points. Balance function in the early and standard discharge groups were significantly longer than those in the late discharge group preoperatively.Conclusions: Total knee arthroplasty is useful for restoring lower limb function, as both ambulation and balance function were significantly improved 3 months after surgery. Although a longer hospital stay with rehabilitation not always affected ambulation and balance function, preoperative ambulation and balance function may predict the length of hospital stay after surgery. No further improvement in ambulation or balance was recognized beyond 3 months, suggesting that further rehabilitation after hospital discharge is needed.