The effect of patient weight on the functional outcome of total knee arthroplasty.

Overweight patients are often considered poor candidates for total knee arthroplasty. For assessment of the validity of this proscription, two-year follow-up data from 109 patients were analyzed. Hospital for Special Surgery Scores were recorded, roentgenograms were inspected for radiolucencies, and isokinetic strength tests were conducted. Surgical time, the presence and severity of radiolucencies, and isokinetic joint strength were found to have statistically significant, positive correlations with patient weight. The Hospital for Special Surgery Score was found to have negative correlations with weight for those patients weighing less than 80 kg, and it was found to have negative correlations with the percentage by which patients were heavier than their ideal weights. However, multiple regression analyses indicated that these correlations were caused by patient gender and not by any independent effect due to weight. From a clinical point of view, the results of this study suggest that orthopedists can expect their overweight total knee patients not to be at a significant postoperative functional disadvantage because of their weight during the initial, two-year postoperative period.