Effect of Partial and Complete PCL Sectioning in Medial Congruent TKA on Femoral Rollback and Posterior Sag - A Computational Study

Description

This presentation from the ISTA 2024 conference held in Nashville, focuses on the biomechanical effects of retaining versus resecting the posterior cruciate ligament (PCL) during medial congruent total knee arthroplasty (TKA). The speaker begins by acknowledging the audience and presenting disclosures.



They explain how media congruent polyethylene designs are intended to improve joint stability and kinematics in TKA, especially with the addition of an "interior lip media" that affects bone movement. The discussion then moves towards the controversy surrounding the PCL, highlighting its role in enhancing femoral rollback and the implications of its resection. The speaker notes that while retaining the PCL promotes femoral rollback, excessive inflection could necessitate its partial or complete removal, which may lead to undesirable posterior translation of the femur, referred to as "posterior sac."



A central focus of the presentation is assessing how PCL resection impacts femoral movement and posterior sag under varied tibial insert conditions. The methodology includes using a physics-based computational model simulating cadaveric knee joints to measure translation of both femur and tibia. Experimental results reveal that PCL resection diminishes femoral rollback and enhances posterior sag, whereas partial resection offers a middle-ground effect. Additionally, increasing the thickness of the tibial insert can reduce posterior sag but doesn't completely counteract the effects of PCL removal.



In conclusion, the findings suggest that resecting the PCL adversely affects knee mechanics in medial congruent TKA, indicating the anterior lip design is insufficient to control movement patterns effectively when the PCL is removed. The implications reiterate the necessity to consider the PCL's role in knee arthroplasty to maintain functional stability.

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