Role of the Posterior Cruciate Ligament in Knee Arthroplasty
Introduction
The posterior cruciate ligament (PCL) is the principal ligament resisting posterior translation of the tibia relative to the femur. In total knee arthroplasty (TKA), its status is important because removal or preservation of the PCL alters knee kinematics, flexion-gap balancing, femoral component design, polyethylene conformity and the amount of prosthetic constraint required. The decision is not simply anatomical; it depends on the integrity and function of the ligament, deformity, bone quality, soft-tissue balance, implant philosophy and the surgeon’s ability to obtain stable flexion and extension gaps.
In conventional TKA, the anterior cruciate ligament is generally excised. The PCL may either be retained, as in a cruciate-retaining design, or excised and functionally replaced by a posterior-stabilized mechanism or another form of increased articular conformity. Thus, PCL management is a central determinant of the relationship between the femoral and tibial components.
Anatomy and Biomechanical Functions of the PCL
Anatomy
The PCL extends from the lateral surface of the medial femoral condyle to the posterior intercondylar area of the tibia. It is composed functionally of two major bundles:
- Anterolateral bundle: relatively tight in flexion and more relaxed in extension.
- Posteromedial bundle: relatively tight…