PCL Tear

The posterior cruciate ligament (PCL) is the strongest ligament in the knee, running inside the joint from the posterior tibia to the medial femoral condyle, preventing the tibia from sliding backward. PCL tears most commonly occur from a direct blow to the front of the flexed knee or from a fall on the knee with the foot plantarflexed. PCL tears are less common than ACL tears and are more often isolated.

Isolated PCL tears often have a better prognosis than ACL tears — many patients with isolated grade I–II PCL tears regain full function with rehabilitation alone. Combined ligament injuries are more disabling.

Posterior knee pain and swelling after a direct blow. The posterior drawer test — pressing the tibia backward on the femur with the knee at 90° — shows increased posterior translation. The "posterior sag sign" (tibia drops posteriorly relative to femur when lying supine) may be visible. MRI confirms the tear and evaluates associated injuries.

Grade III PCL tears, combined ligament injuries (posterolateral corner, ACL), and cases with persistent functional instability after rehabilitation are considered for surgical reconstruction.

External patient-education references and related OSI pages for additional background:

• Britannica — Ligament
• Britannica — Knee (anatomy)
• AAOS OrthoInfo — patient education library
• OSI glossary — orthopedic terminology in plain language