Posterior Condylar Offset Ratio and Anterior Femoral Cut between Anterior and Posterior Referencing Systems in Total Knee Arthroplasty

Background: The postoperative posterior condylar offset ratio (PCOR) and the anterior femoral cut (AFC) after total knee arthroplasty in the anterior referencing system (ARS) and posterior referencing system (PRS) are controversial. Objective: To compare PCOR and AFC in both referencing systems. Materials and Methods: The present study was a retrospective study that included 331 patients with 443 knees that underwent primary PSTKA. The patients were divided into two groups according to the referencing system. One hundred four knees were selected for the ARS and 104 knees were selected for the PRS by using the systematic sampling method. Preoperative PCOR, postoperative PCOR, and AFC were measured and compared in each group and between groups. Results: Preoperative PCOR and postoperative PCOR in the ARS and PRS were 0.47 (SD 0.04). Postoperative PCOR in the ARS and PRS were not significantly different (p=0.43). The gaps between the tip of the anterior flange of the femoral component and anterior femoral cortex were 24.04% in the ARS and 28.85% in the PRS, with no statistically significant difference (p=0.43). Anterior femoral notching was not found in either group. Conclusion: Both ARS and PRS could preserve the PCOR and showed no statistically significant difference in the AFC after total knee arthroplasty. Keywords: Posterior condylar offset ratio; Anterior referencing system; Posterior referencing system; Anterior femoral cut; Total knee arthroplasty