Return to regular sports activity was evaluated in a retrospective review of 160 patients who had undergone total knee replacement surgery by a single surgeon (208 knee replacements). Mean age of the patients was 68 years (range, 27 to 87) at surgery and 73 years (range, 33 to 91) at review at a mean follow-up of 5 years (range, 3 to 7). Seventy-nine patients regularly participated in sports, at least once per week, before surgery, and 51 patients regularly participated in sports after surgery. Only eight patients took up sports after surgery who were not regularly involved in sports in the year before surgery. Patients were more likely to return to low-impact activities such as bowls (29 of 32, or 91%) than to high-impact activities such as tennis (6 of 30, or 20% returned). Forty-three of 56 patients (77%) who had participated in regular exercise in the year before surgery returned to sports. Eighty patients did not participate in sports before surgery and 54 of these had coexisting disease that prevented sports. None of these patients returned to sports.