Preoperative factors related to the ambulatory status at 1 year after total knee arthroplasty

Purpose: The purpose of this study is to investigate whether preoperative factors can predict the ambulatory status at 1 year after primary total knee arthroplasty (TKA). Methods: The subjects were 115 patients who had undergone TKA. Isometric lower limb muscle strength was measured and the Timed Up and Go (TUG) test and the 2011 knee society scoring were conducted preoperatively. Then, the patients were divided into two groups after surgery: a cane-assisted walking group (n = 42) and independent walking group (n = 73). Unpaired t-test, chi-square test, Mann-Whitney U-test, logistic regression analysis and the receiver-operating characteristic curve analysis were used in this study. Results: A multiple logistic regression analysis selected age, TUG test and functional activities as significant variables estimating the use of a cane after surgery. Receiver-operating characteristic curve analyses revealed that the cut-off score for TUG test was 10.8s (sensitivity =69%, specificity =67%, area under curve =0.81) and the cut-off score for functional activities was 39 points (sensitivity=83%, specificity =63%, area under curve =0.83) in predicting the ambulatory status. Conclusions: Preoperative TUG test with a cut-off score of 10.8s and functional activities with a cut-off score of 39 points are reliable assessment tools for predicting the use of walking aid following TKA. IMPLICATIONS FOR REHABILITATION An accurate prediction of the ambulatory status after total knee arthroplasty can aid patients in understanding their own goals of the activities of daily living. Preoperative timed up and go test of <10.8s and a preoperative functional activities functional activities score in the 2011 knee society scoring >39 points are useful for predicting the ambulatory status after total knee arthroplasty.