Obesity and osteoarthritis

This paper provides an up-to-date review of obesity and lower limb osteoarthritis (OA). OA is a major global cause of disability, with the knee being the most frequently affected joint. There is a proven association between obesity and knee OA, and obesity is suggested to be the main modifiable risk factor. Obese patients (Body Mass Index, BMI, over 30kg/m(2)) are more likely to require total knee arthroplasty (TKA). The global prevalence of obesity has doubled since 1980; by 2025, 47% of UK men and 36% of women are forecast to be obese. This rising global burden is a key factor in the growing rise in the use of TKA. It is therefore important to appreciate the outcomes of surgery in patients with end-stage OA and a high BMI. This review found that while OA is felt to contribute to weight gain, it is unclear whether TKA facilitates weight reduction. Surgery in obese patients is more technically challenging. This is reflected in the evidence, which suggests higher rates of short- to medium-term complications following TKA, including wound infection and medical complications, resulting in longer hospital stay, and potentially higher rates of malalignment, dislocation, and early revision. However, despite slower initial recovery and possibly lower functional scores and implant survival in the longer term, obese patients can still benefit from TKA in terms of improved function, quality of life and satisfaction. In conclusion, despite higher risks and more uncertain outcomes of surgery, higher BMI in itself should not be a contraindication to TKA; instead, each patient's individual circumstances should be considered.