Total Ankle Replacement in Obese Patients: Component Stability, Weight Change, and Functional Outcome in 118 Consecutive Patients

Abstract

Obesity is a growing problem in Europe and the United States. While obesity has been linked to poor outcomes after total knee or hip replacement, there are no data addressing outcomes in obese patients who underwent total ankle replacement (TAR). This retrospective chart review included 118 patients (123 ankles) with a minimum body mass index (BMI) of 30 kg/m2 who underwent TAR between May 2000 and June 2008. There were 61 male (51.7%) and 57 female (48.3%) patients with a mean age of 59.8 +/- 11.6 years (range, 25.4 to 85.0). All patients were evaluated pre- and postoperatively (mean followup 67.7 +/- 27.0 months; range, 29 to 126). Radiological outcomes were assessed using standardized weightbearing radiographs. Clinical outcomes were assessed using the visual analogue scale (VAS) and American Orthopaedic Foot and Ankle Society (AOFAS) hindfoot scale. There were nine intraoperative complications. All patients experienced significant pain relief (VAS change from 7.0 +/- 1.7 to 1.4 +/- 1.1, p < 0.001) and functional improvement (AOFAS score change from 35.4 +/- 14.9 to 75.4 +/- 9.6, p < 0.001; total ROM change from 26.9 +/- 13.7 to 35.3 +/- 8.1 degrees, p < 0.001). BMI measured preoperatively, and at 1 and 2 years postoperatively was 32.9 +/- 2.5 (range, 30.0 to 40.0) kg/m2, 32.4 +/- 2.4 (range, 28.6 to 41.0) kg/m2, and 32.2 +/- 2.4 (range, 28.6 to 40.5) kg/m2, respectively. Gender had a significant effect on weight loss, but not age or postoperative sports activity. Revision surgery was performed in six patients, resulting in a 6-year survivorship of 93%. Our findings confirm that TAR gives significant pain relief and functional improvement. In this study, the survivorship of the prosthesis components was comparable to the results obtained in non-obese patients.