Abstract

Aim
Obesity is associated with higher rates of complications following total knee arthroplasty (TKA) hence bariatric surgery (BS) has been proposed as a preoperative optimisation strategy to mitigate obesity-related risks. However, existing literature presents conflicting evidence regarding whether BS affects the risk of revision after TKA. The objective of this study was to evaluate the effect of prior BS on revision rates following primary TKA in obese patients, and to assess whether the type or timing of BS influences these outcomes.

Method
MEDLINE, Embase, CENTRAL, and PubMed were searched through March 2025. Studies were eligible if they included obese adults undergoing primary TKA, comparing outcomes between those with and without prior BS. The primary outcome was revision surgery (short-term ≤90 days, long-term >90 days); secondary outcomes included indications for revision and subgroup analysis by BS type and timing. Risk of bias was assessed using RoB-2 and ROBINS-I tools.

Results
Fifteen studies were included (n=3,241,049; BS group n=130,029). Pooled meta-analyses showed no significant difference in revision risk between BS and non-BS groups at 90 days (OR 1.24, 95% CI 0.66–2.34) or at 1–2 years (ORs 0.98–1.24; all p>0.05). Heterogeneity was high (I² >90%). Type of BS did not consistently affect revision risk. Data regarding timing of TKA suggests lower revision risks when performed within 2 years of BS.

Conclusions
Our pooled analysis showed that prior bariatric surgery did not significantly impact revision rates after TKA. Future research should prioritise prospective studies and long-term registry follow-up.