The Effect of Congruent Tibial Inserts in Total Knee Arthroplasty: A Network Meta- analysis of Randomized Controlled Trials

Objective: This study aims to determine whether modern ultracongruent tibial inserts are associated with different outcomes in Total Knee Arthroplasty (TKA). Background Ultracongruent fixed-bearing (UCFB) and medial congruent fixed-bearing (MCFB) inserts have been known to be effective in total knee arthroplasty with patient satisfaction. Nonetheless, no supporting evidence to date exists to rank the clinical outcomes of these various congruent inserts in TKA. Methods We searched for PubMed, Embase, The Cochrane Central Register of Controlled Trials, Web of Science, and Scopus up to May 15, 2022. We selected studies involving an active comparison of UCFB or MCFB in TKAs. We performed a network meta-analysis (NMA) of randomized controlled trials (RCTs) and compared different congruent inserts. We ranked the clinical outcomes by SUCRA score with the estimate of the best treatment probability. Our primary outcomes were revision rates and radiolucent lines. Secondary outcomes were functional scores, including the range of motion (ROM), the Knee Society Score (KSS), Oxford Knee Score (OKS), and WOMAC. Results 18 RCTs with 1793 participants were obtained. The MCFB performed similar revision rates as CRFB and PSRP. CRFB and UCFB had the lowest radiolucent lines. UCFB and MCFB had the best OKS score overall. Conclusions The ranking probability for better clinical outcomes in congruent inserts demonstrated the superiority of congruent tibial inserts, including UCFB and MCFB. UCFB may be associated with improved postoperative functional outcomes. However, integrating future RCTs for high-level evidence is necessary to confirm these findings.