Mean BMI of Overweight and Obese Patients Does Not Decrease After Successful Ankle Reconstruction

BACKGROUND:End-stage arthritis may be associated with increased body mass index (BMI). Overweight patients with ankle arthritis often request surgery in the hope that this will allow them to initiate a weight loss program. METHODS:One hundred and forty-five overweight (BMI = 25.1 to 29.9 kg/m) or obese (BMI > 30 kg/m) patients who had successful ankle replacement or ankle fusion, as defined by the absence of revision ankle surgery and a postoperative improvement in the Ankle Osteoarthritis Scale (AOS) score, were identified in a retrospective cohort ankle database. Their BMIs at six months and one, two, and five years postoperatively were compared with their preoperative BMI as the primary outcome measure. Linear regression analysis was used to correlate the outcome scores against BMI with time. RESULTS:No significant change in the mean BMI, compared with the preoperative BMI, was found at six months or one, two, or five years postoperatively, despite significant improvement in the AOS and Short Form-36 (SF-36) Physical Component Summary scores at all time points. The factor that most strongly correlated with postoperative BMI was preoperative BMI. CONCLUSIONS:Pain and disability are significantly reduced in overweight and obese patients after successful ankle replacement or fusion. Despite this, the mean BMI remains unchanged after the surgery, indicating that weight loss does not commonly occur following successful ankle reconstruction in this patient population. Obesity is likely attributable to factors other than limited mobility caused by ankle arthritis. LEVEL OF EVIDENCE:Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.