Anatomy of the Posterior Cruciate Ligament and its Length Patterns During Knee Flexion

We dissected 10 cadaver knee joints to determine the exact site, shape, and width of attachments of the posterior cruciate ligament. The tibial attachment was on the sloping posterior portion of the tibial intercondylar area and extended 11.5–17.3 mm distal to the tibial plateau. The femoral attachment was to the antero-inferior portion of the lateral aspect of the medial femoral condyle. The tibial attachment was oval and averaged 11.9 mm. The fan-shaped femoral attachment was, on average, 1.7 times wider than the tibial. In each knee, the posterior cruciate ligament was split into six longitudinal fibre bundles. The distance between the femoral and tibial attachment of each bundle was measured at 0, 30, 60, 90, and 130° of knee flexion. No part of the posterior cruciate ligament remained the same length during knee flexion. The greatest change in tibio-femoral distance occurred in the fibres that were attached distally on the femur and anteriorly on the tibia; the least change occurred in fibres attached proximally on the femur and posteriorly on the tibia. These results can be used during reconstruction of the posterior cruciate ligament to help the surgeon determine the best site for attaching the graft.