Effect of Computer-guided Operations on Improving the Distal Femoral Flexion Angle on the Sagittal Placement of Femoral Prosthesis in Total Knee Arthroplasty.

ABSTRACT

Background: The precise placement of prosthesis in total knee arthroplasty (TKA) surgery significantly impacts the postoperative outcomes and the long-term survival rate of prosthesis. While the optimal coronal position of femoral prosthesis has been extensively researched, there remains a gap in the study of sagittal placement. Therefore, our aim is to investigate the impact of the distal femoral flexion angle (DFFA) on the sagittal placement of femoral prosthesis in TKA. Methods: A total of 88 patients (90 knees) with osteoarthritis were enrolled in this study. To mitigate the impact of DFFA, they were randomly assigned to either the traditional operation group (50 cases) or the computer navigation operation group (40 cases). A comparison was made between the two groups regarding the sagittal femoral prosthesis flexion angle (SFPFA) and the sagittal femoral component angle (SFA). Additionally, linear regression analysis was conducted to analyze DFFA, SFA, and SFPFA. Results: The absolute values of DFFA were (2.27 ± 0.32)° in the navigation group and (2.15 ± 0.27)° in the traditional group (t=0. 30, P = .77). The absolute values of SFPFA were (0.63 ± 0.14)° in the navigation group and (2.40 ± 0.29)° in the traditional group (t =-5. 47, P = .05). The absolute values of SFA were (4.44 ± 0.62)° in the navigation group and (7.20 ± 0.57)° in the traditional group, with SFA being lower in the navigation group compared to the traditional group (t =-3. 28, P = .002). The regression equations between DFFA and SFA in navigation group and traditional operation group were SFA=5. 510-0.979×DFFA (P = .01) and SFA=7. 869-0.971×DFFA (P = .08), respectively. The regression equations between DFFA and SFPFA in navigation group and traditional operation group were SFPFA=0. 105-0.081×DFFA (P = .38) and SFPFA=-0. 96 +0.516 ×DFFA (P = .06), respectively. Conclusion: In TKA, the DFFA can impact the placement position of the femoral prosthesis in the sagittal position. When compared to traditional operation methods, computer-guided operations tend to provide a more precise and accurate sagittal position of femoral prosthesis. This study represents the first investigation into the influence of DFFA on the sagittal placement of femoral prostheses in TKA, addressing a research gap in this area. It further underscores the important role of computer-guided surgery in achieving accurate sagittal alignment of femoral prostheses, suggesting a potential adjunctive approach.