Changes in actual daily physical activity and patient-reported outcomes up to 2 years after total knee arthroplasty with arthritis.

The current study aimed 1) to describe changes in patient-reported outcomes and physical activity measured with an accelerometer preoperatively, 6 months and 2 years postoperatively in older patients undergoing total knee arthroplasty (TKA) for arthritis, and 2) to examine the predictors of the changes in physical activity (PA). This study included 58 patients (mean age 72.6 years, 84.5% women) who completed the Oxford Knee Score (OKS) and the 8-item Short Form Health Survey. Physical activity measured mean steps per day, duration of light physical activity and moderate-to-vigorous physical activity (MVPA) per week. All PA indicators and patient-reported outcomes improved 6 months postoperatively. After 6 months, knee-related pain and function gradually improved, and MVPA increased. The OKS was a sole predictor of improvement in PA during the 2-year study period, suggesting the importance of disease-specific quality of life.