Anatomy of the posterior cruciate ligament as well as the posterolateral and posteromedial structures

The posterior cruciate ligament (PCL) is the strongest ligament of the human knee joint and the primary restraint against posterior tibial translation. It originates at the lateral wall of the medial femoral condyle and inserts into the posterior aspect of the tibial eminence approximately 10 mm below the joint surface. The quadriceps muscle is the functional agonist for the PCL, whereas the hamstrings act as an antagonist pulling the tibia back in 90 degrees of flexion. There are two functional bundles: the strong anterolateral bundle which tightens in flexion and a thin posteromedial bundle which becomes tense in maximal flexion and in extension. The AL bundle originates in the superior aspect of the femoral PCL origin. Under arthroscopic visualization in 90 degrees of flexion the PM bundle originates in the inferior aspect of the PCL origin. When the knee is extended the PM origin rotates backwards. The PM bundle inserts into the posterior aspect of the tibial insertion. The AL bundle inserts into the anterior aspect of the tibial insertion. When creating a tunnel for a PCL reconstruction one should be aware of the proximity of the nerves and vessels within the fossa poplitea. The PCL forms a functional unit with the posteromedial and posterolateral structures. The posteromedial structures are the medial collateral ligament, the posteromedial capsule with its muscular insertions (m. semimembranosus and m. gastrocnemius). The most important structures of the posterolateral corner are the fibular collateral ligament, the lateral m. gastrocnemius, the oblique popliteal ligament, the arcuate popliteal ligament the popliteofibular ligament, and the tendon of them. popliteus. The popliteofibular ligament has an important role for the passive stabilization against rotation. It is highly recommended that concomitant injuries of these structures be addressed when treating PCL injuries.