Does the use of tibial stem extensions reduce the risk of aseptic loosening in obese patients undergoing primary total knee arthroplasty: A systematic review and meta-analysis.

BACKGROUND: This study aimed to compare the risk of revision for aseptic loosening in obese (body mass index >30 kg/m2 ) patients with stemmed (ST) versus non-stemmed (NST) tibial implants in primary total knee arthroplasty (TKA).

METHODS: A systematic review and meta-analysis were conducted following PRISMA and MOOSE guidelines. Studies reporting a direct comparison between ST and NST tibial implants in obese patients were included. The primary outcome of interest was revision for aseptic loosening. Outcomes were analysed using meta-analysis of relative risk. Risk of bias assessment was performed using the Newcastle-Ottawa Scale for observational studies and the RoB-2 Cochrane tool for randomised studies.

RESULTS: Seven studies met the selection criteria, consisting of four cohort studies and three randomised controlled trials. Mean follow up time for the eligible cohort was 62.6 months. Meta-analysis demonstrated a statistically significant reduction in the risk of aseptic revision in the ST group compared with the NST group (risk ratio 0.25, 95% confidence interval 0.07 to 0.92). After removal of all zero-event studies, the results remained in favour of the ST group (risk ratio 0.15, 95% confidence interval 0.03 to 0.64).

CONCLUSIONS: This study found that obese patients undergoing TKA with stemmed tibial implants may have a lower risk of aseptic revision compared with those with non-stemmed tibial implants. However, due to the lack of high-quality literature available, our study is unable to draw a definitive conclusion on this matter. We suggest that this topic should be re-evaluated using higher-quality study methods, particularly national joint registries studies and randomised controlled trials.