Overview Snapshot A 35-year-old man presents to the emergency department after sustaining an injury to the knee while playing football. An opposing player's helmet collided with his anterior proximal tibia. After the event, the patient experienced posterior knee pain, mild swelling, and limped off the football field. Physical examination is notable for antalgic gait and a positive posterior drawer test. Preparations are made to obtain a magnetic resonance imaging of the affected knee. Introduction Clinical definition injury of the posterior cruciate ligament (PCL) Epidemiology risk factors high-energy trauma (e.g., motor vehicle accident) sport activities Etiology trauma that posteriorly translates the proximal tibia Pathoanatomy normal anatomy the largest intraarticular ligament in the knee originates from the lateral portion of the medial femoral condyle and inserts at the fovea centralis (PCL facet) pathology posteriorly directed shear force when the knee is flexed "dashboard injury" (high-energy trauma) when the proximal tibia collides with the dashboard of a car in a motor vehicle accident sports injuries (low-energy trauma) the player falls on their knee while it is flexed and the foot is plantarflexed direct trauma to the anterior knee Associated conditions high-energy trauma can result in PCL injury as well as injury to the posterolateral corner anterior cruciate ligament medial collateral ligament Prognosis insufficient evidence to determine the true prognosis Presentation Symptoms may present with posterior knee pain athletes may continue playing sports and not seek medical care Physical exam posterior drawer test the proximal tibial is pushed posteriorly to assess for PCL laxity while the knee is flexed at 90 degrees posterior translation is considered a positive test mild-to-moderate effusion slight limp or antalgic gait may have impaired terminal knee flexion Imaging Radiography indication performed initially to assess for fractures Magnetic resonance imaging (MRI) indication typically performed in all patients presenting with acute PCL injury highly sensitive and accurate for acute PCL injury Studies Making the diagnosis a presumptive diagnosis can be made based on clinical presentation MRI can definitively diagnose acute or subacute PCL injury Differential Anterior cruciate ligament injury distinguishing factor patients typically hear a "pop" after injury and there is typically significant edema and joint effusion patients have a positive anterior drawer test Treatment Conservative rest, ice, compression, and elevation (RICE) therapy indication standard management of patients with an isolated PCL injury in addition to RICE therapy, patients should receive nonsteroidal anti-inflammatory drugs (NSAIDs) or acetaminophen for pain management immobilization in extension (e.g., hinged knee brace) Operative reconstructive surgery indication typically reserved for acute and multi-ligamentous knee injuries Complications May result in osteoarthritis