Diabesity is associated with a worse joint specific functional outcome following primary total knee replacement

The combined effect of diabetes mellitus and obesity (Diabesity) on total knee replacement (TKR) outcomes is unclear. This study aimed to assess whether diabesity influenced functional outcomes and complication rate following primary TKR.

This case-controlled study compared the independent effects of obesity, diabetes, and diabesity on TKR outcomes. Data were collected pre-operatively and 12 months post-operatively from a single study centre. Outcomes included Oxford Knee Score (OKS), EuroQol 5-dimensions (Eq. 5D), post-operative satisfaction and complication rate.

There were 2577 TKRs in the cohort, of which 244 (9.5%) had diabesity. Diabesity was independently associated with reduced pre-operative OKS (-1.14 points, 95% CI -1.97 to -0.31, p = 0.007) and OKS improvement (-2.37 points, 95% CI -3.11 to -1.62, p < 0.001). Obesity was also independently associated with worse pre-operative OKS (-0.78 points, 95% CI -1.28 to -0.27, p = 0.003) and OKS improvement (-0.81 points, 95% CI -1.26 to -0.35, p = 0.001). Both diabesity (-0.05 points, 95% CI -0.08 to -0.02, p = 0.003) and obesity (-0.02 points, 95% CI -0.04 to 0.00, p = 0.039) were associated with worse pre-operative Eq. 5D score. Patients with diabesity reported reduced post-operative satisfaction due to obesity independently (OR 0.75, 95% CI 0.56 to 1.00, p = 0.048). Diabesity was not independently associated with post-operative complications.

Diabesity was independently associated with a worse knee-specific function and Eq. 5D score pre-operatively, and diminished joint specific functional improvement following TKR. Patients with diabesity also experienced reduced post-operative satisfaction due to obesity independently.