The relationships between body weight and joint replacement are debated often in the orthopaedic community. Some surgeons are so concerned about perioperative complications related to obesity that they recommend delaying arthroplasty in obese patients until weight loss is achieved.
But what are the likelihood and implications of weight changes after joint replacement? For those answers, in the June 3, 2015 edition of JBJS, Ast et al. tracked differences in body mass index (BMI) among nearly 7,000 patients for two years after total hip arthroplasty (THA) or total knee arthroplasty (TKA). Establishing a 5% BMI change as “clinically meaningful,” the researchers found that:
- Most patients (73% of those undergoing THA and 69% of those undergoing TKA) experienced no weight change.
- Female patients, patients with a higher preoperative BMI, and those undergoing TKA were most likely to lose weight after surgery.
- Weight loss was associated with improved clinical outcomes after THA, but not after TKA. However, weight gain in general was associated with inferior clinical outcomes.
- Those with better preoperative functional status were less likely to gain weight after THA or TKA.
Countering conventional wisdom that weight loss after total joint arthroplasty is unlikely, Ast. Et al. emphasize that “obese patients who undergo total joint arthroplasty are more likely than non-obese patients to lose weight after surgery.”