Preoperative predictors of locomotor ability two months after total knee arthroplasty for severe osteoarthritis

OBJECTIVE: To identify preoperative predictors of locomotor ability 2 months after total knee arthroplasty (TKA). METHODS: Sixty-five participants scheduled for a first TKA were recruited. The dependent variable was the distance covered during the 6-minute gait test 2 months after TKA. The independent variables, measured before surgery, were grouped into 3 categories: 1). personal; 2). organic system, and 3). capability variables. Multiple regression analyses were conducted to determine the best predictors of the dependent variable. Modified cross-validation of the model combining predictors from the three categories was obtained with 10 random samples derived from the original cohort by resampling with replacement. RESULTS: Predictors were identified in the 3 categories: 1). gender, number of comorbidities, body mass index, 2). knee pain, flexion and strength, lower limb mechanical power, and 3). preoperative 6-minute gait distance. When these variables were modeled together only the preoperative 6-minute gait distance and knee pain and flexion remained significant (adjusted R(2) = 0.66). CONCLUSION: Using variables easily measured before surgery, it is possible to predict with good accuracy locomotor ability 2 months after TKA.