Total knee arthroplasty in obese patients. We examined 182 patients (257 knees) who had had a total knee arthroplasty two to five six years earlier. The patients were grouped into five weight classes. Eighteen patients (twenty-seven knees) were considered moderately obese and twelve patients (twenty-seven knees), severely obese. The results in all but four knees were rated excellent or good. One patient needed a revision procedure for late infection, and the result was rated poor. Three results were rated fair. There was no discernible difference in the over-all scores among the five weight groups. However, 30 per cent of the knees of the moderately and severely obese patients had patellofemoral symptoms, whereas the incidence was 14 per cent in the other groups (p less than 0.03). No clear-cut association was found between obesity and either thrombophlebitis or complications related to the wound. 