Weight loss intervention before total knee arthroplasty-feasibility and safety

Background: Annually 8500 total knee arthroplasty (TKA) are performed in Denmark. About 80% of this population is overweight or obese. The present material is part of a longitudinal randomized study (ClinicalTrial.gov: NCT01469403). Objectives: To investigate whether it is feasible and safe to implement an intensive weight loss program in order to reduce preoperative body weight of obese patients before TKA surgery. The primary aim of the Weight Loss Intervention before Total Knee Arthroplasty (WITKA) study is to investigate whether weight loss interventions before total knee arthroplasty (TKA) will improve QoL and physical function 1 year after surgery. Methods: We conducted a single-blind, randomized study. Eligible patients were scheduled for TKA due to osteoarthritis (OA) of the knee and obesity (BMI >30kg/m2). Participants were randomized to either a control group that followed the standard care or a weight loss group that followed a low-energy diet (810 kcal/day) 8 weeks before surgery. Outcomes were assessed before intervention for the weight loss group, and within 1 week preoperatively for both the weight loss group and the control group. The primary outcome in the WITKA study was the Short-Form 36 (SF-36). Secondary outcomes were Knee injury and Osteoarthritis Outcome Score (KOOS), 6 Minutes' Walk Test, and body composition. Results: Included were 77 patients (weight loss group n=38; control group n=39), 71% were females, the mean age was 65 years (range 46-85), and the average BMI was 31. The average weight loss after 8 weeks was 10.7 kg (10% of body weight). According to dual energy X-ray absorptiometry (DXA), the weight loss consisted of a 6.7 kg reduction in fat mass, a 3.0 kg reduction in lean body mass, and lean body mass increased by 2.3%. In addition, cholesterol decreased and systolic blood pressure decreased by 12 mm/Hg. The intensive diets had few and mild adverse effects. Serious cardiac complications were found in two cases in the intervention group and in one case in the control group. All three patients later underwent TKA without complications. No perioperative complications were recorded in any group. Conclusions: Our results suggest that it is feasible and safe to implement an intensive weight loss program shortly before TKA.