A Prospective, Longitudinal Study of Patient Activity Levels Following Total Knee Arthroplasty Stratified by Demographic and Comorbid Factors

With the marked increase in the annual number of total knee arthroplasties (TKAs) in the United States, there has been an increased interest in evaluating patient-reported outcomes. The purpose of this study was to prospectively and longitudinally evaluate temporal trends in patient activity levels following TKA and to identify potential demographic and comorbid factors that may affect these outcomes. This prospective study evaluated 281 patients, including 108 men and 173 women, who had a mean age of 66 years (39-80 years) and underwent primary TKA. All patients were followed for a minimum of 2 years. Medical comorbidities were recorded preoperatively and activity scores were evaluated at each follow-up visit. The effects of different patient demographics and systemic comorbidities on activity outcomes were further analyzed using multivariate regression analysis. Compared with preoperative levels, the activity score was observed to initially significantly decrease at 6 weeks postoperatively to below preoperative levels (9.2 vs. 8.1 points). By 3 months, scores were above preoperative levels (10.3 points), but below peak levels. A significant peak in the activity score was observed at 2-year follow-up after which there were no significant differences in scores at 5 years (11.49 vs. 11.47 points). In evaluating patient demographics and comorbidities, significant negative impact of older age, tobacco use, history of cancer, cardiovascular disease, lymphatic disease, and renal disease can be seen on activity levels. Activity scores following TKA follow a temporal trend in which scores initially drop below preoperative levels after surgery, but recover and reach a peak at 2 years postoperatively. This peak was maintained at 5-year follow-up. Surgeons should counsel their patients that they will not perceive the full benefit of a TKA until 1 to 2 years after surgery, in addition, patients may actually perceive their progress to decrease initially. Also, their improvements at 2-year follow-up are likely to remain constant for at least 5 years. However, certain demographic and comorbidities may negatively impact patient activity outcomes.