Effect of Posterior Cruciate Ligament Resection on Gap Balancing in Robot‐assisted Total Knee Arthroplasty

Abstract

OBJECTIVE: Retention or sacrifice of the posterior cruciate ligament (PCL) is one of the most controversial issues while performing total knee arthroplasty (TKA). This study aimed to evaluate the impact of PCL resection on flexion-extension gaps, femoral component rotation, and bone resection amounts during robot-assisted TKA. METHODS: , respectively. The guidance module and camera stand assembly were used to capture gaps before and after PCL resection. Measurements of femoral component rotation and bone resection amounts were made in cruciate-retaining (CR) TKA mode and PS-TKA mode. RESULTS: After PCL resection, the mean change in the medial and lateral compartments of flexion gaps increased by 2.0 and 0.6 mm, respectively (p < 0.001). Compared with the CR-TKA mode group, the bone resection amounts of the medial posterior condyle and the lateral posterior condyle in the PS-TKA mode group decreased by 2.0 ± 1.1 and 1.1 ± 1.1 mm, respectively, and the external rotation of the femoral prosthesis relative to the posterior condylar axis and trans-epicondylar line was reduced by 1.0° ± 1.3° and 1.2° ± 1.6°, respectively (p < 0.001). CONCLUSION: The release of the PCL did not affect the extension gap, but significantly increased the flexion gap. Moreover, the increases in the medial flexion gap were greater than those of the lateral flexion gap. After PCL resection, less external rotation of the femoral prosthesis and fewer bone cuts of the posterior femur were needed in PS-TKA.