Comparison of functional outcomes between single-radius and multi-radius femoral components in primary total knee arthroplasty: a meta-analysis of randomized controlled trials

Purpose Our purpose in the current meta-analysis was to compare the functional outcomes in patients who have received single-radius (SR) or multi-radius (MR) femoral components in randomized controlled trials (RCTs) for primary total knee arthroplasty (TKA). The hypothesis was that there would be no statistically significant difference between two groups in terms of functional outcomes. Materials and methods We searched the international electronic databases PubMed, Embase, and the Cochrane Central Register of Controlled Trials up to February 2020 for RCTs that compared functional outcomes of SR and MR femoral component designs after primary TKA. We performed a meta-analysis of nine RCTs using the Knee Society Score for the knee (KSS-knee), KSS-function, Knee Injury and Osteoarthritis Outcome Score (KOOS), Oxford Knee Score (OKS), degree of knee flexion, extension, and complications, including postoperative infection and revision surgery. Results The meta-analysis revealed no statistically significant differences in all the analyzed variables, including KSS-knee, KSS-function, KOOS, OKS, knee flexion, and knee extension. For postoperative complications, no statistically significant differences were detected for femoral component designs in postoperative infection or incidence of revision surgery between the two groups. Conclusions The current meta-analysis of RCTs did not show any statistically significant differences between SR and MR femoral component designs in terms of postoperative functional outcomes. Evaluated outcomes included functional outcome scores, degree of knee flexion, extension, and complications. However, because of the limited clinical evidence of this study owing to the heterogeneity between the included RCTs, a careful approach should be made in order not to arrive at definite conclusions.