Obesity and hypertension predict joint replacement surgery outcomes

Metabolic abnormalities affect patient function negatively after joint replacement surgery, possibly because of the systemic proinflammatory state. Obesity and hypertension are important predictors for hip surgery outcomes, and obesity predicts knee surgery outcomes.

Gandhi and coworkers reviewed patients who had primary knee or hip replacement and at least 1 metabolic syndrome (MetS) risk factor. Age, sex, and comorbidity were recorded. MetS risk factors of interest were body mass index (BMI) greater than 30 kg/m², diabetes mellitus, hypertension, and hypercholesterolemia. Western Ontario McMaster University Osteoarthritis Index (WOMAC) scores at baseline and 1 year were compared by number of MetS risk factors. Linear regression modeling was used to evaluate the effects of the MetS risk groups and the individual metabolic abnormalities.

Patients in the knee and hip groups showed a significant difference in sex distribution, BMI, and mean comorbidity across risk groups. Baseline and 1-year WOMAC scores increased significantly with increasing number of MetS risk factors for patients in both groups. The regression model with the individual metabolic abnormalities was more predictive of outcome than one with the number of risk factors present.

The authors noted that this knowledge should be used when counseling patients before surgery.