Obesity, OA, and the Need for Knee Replacement

Kevin Deane, MD, PhD


May 31, 2016

Obesity and the Relative Risk of Knee Replacement Surgery in Patients With Knee Osteoarthritis

Leyland KM, Judge A, Javaid MK, et al
Arthritis Rheumatol. 2016;68:817-825

Study Summary

For this study, Leyland and colleagues used a large database in Spain to evaluate factors associated with knee replacement in a cohort of patients with knee osteoarthritis (OA).

They found that the risk for knee replacement steadily increased as body mass index (BMI) increased, which was classified using the World Health Organization BMI categories. In particular, for patients in the highest BMI category (ie, obese III or a BMI of ≥ 40 kg/m2), the risk for knee replacement was the highest (adjusted hazard ratio: 2.67; 95% confidence interval: 2.34-3.04).

The authors concluded that among patients with OA, weight reduction strategies could potentially reduce the need for knee replacement by 31%.


This article joins emerging research that links obesity to risk for either incident rheumatic disease (eg, OA, rheumatoid arthritis, psoriatic arthritis, and gout), progressive rheumatic disease (eg, rheumatoid arthritis), or comorbidities (eg, cardiovascular disease). Taken together with the other known adverse associations with obesity (eg, diabetes and some cancers), weight loss could be a key factor to improve public health.

Unfortunately, identifying another adverse effect of obesity will not make implementation of weight reduction strategies any easier. However, the findings from this study will hopefully provide healthcare providers with a strong discussion point about weight loss when caring for patients with both OA and obesity.