Posterior Cruciate Ligament (Full)

ligamentum cruciatum posterius (complete)

The PCL is the strongest intra-articular knee ligament, acting as the primary restraint against posterior tibial translation. It has two bundles: the anterolateral (tightest in flexion — larger and primary) and posteromedial (tightest in extension). Isolated PCL tears are managed non-operatively in most cases; combined PCL-PLC or PCL-ACL tears require surgical reconstruction with allograft or autograft using single or double-bundle techniques.

Region: Knee

Anatomical Data

Origin, Insertion & Supply

Origin	Posterior intercondylar area of the tibia (posterior tibial surface — 1 cm below the joint line)
Insertion	Anterior lateral surface of the medial femoral condyle (occupying a larger femoral footprint than the ACL)

Biomechanics

Function & Actions

Actions	Primary restraint against posterior tibial translation at all flexion angles; the strongest knee ligament (tensile strength 2000 N vs ACL 2200 N); the axis of knee rotation

Clinical Relevance

Clinical Notes

The posterior drawer test (posterior translation of the tibia at 90 degrees of flexion), quadriceps active test (quadriceps contraction reducing posterior sag), and posterior sag sign (tibial posterior drop in supine with both hips and knees at 90 degrees) confirm PCL deficiency. Tibial inlay reconstruction (direct posterior tibial attachment) avoids the acute angle of transtibial tunnel techniques.

Pathology

Common Injuries & Conditions

Isolated PCL Tear

Posterior tibial translation from dashboard or hyperflexion mechanism — isolated Grade I-II tears managed non-operatively; Grade III or combined injuries require PCL reconstruction.