Knee arthroplasties have similar results in high- and low-activity patients.

With increased patient demand to return to active lifestyles, total knee arthroplasties have evolved from primarily providing pain relief to allowing for increased function and mobility. We evaluated the influence of activity on the outcome of total knee arthroplasties. The overall satisfaction, rate of revision, and clinical and radiographic results for high-activity patients were compared with a matched group of low-activity patients at a minimum followup of 4 years (mean, 7 years; range, 4-14 years). There were 22 men and 35 women (72 knees) in each group. High-activity patients fared as well as their low-activity counterparts with no differences in clinical outcomes. At the time of last followup, mean Knee Society objective scores were 95 points (range, 70-100 points) and 96 points (range, 80-100 points) for the high-activity and low-activity groups, respectively. The high-activity group had one clinical failure, and neither group had any revisions. The groups had similar radiographic outcomes with no progressive radiolucencies and no evidence of osteolysis. While we await long-term results, these results suggest that low- to moderate-impact sports activities had no effect on the clinical and/or radiographic outcomes of total knee arthroplasties at mid-term followup.