What should you know about PCL avulsion injury?

The PCL helps limit backward movement of the shin bone relative to the thigh bone. In an avulsion, the ligament may remain attached to a bone fragment that has been pulled from its usual attachment. A force to the front of a bent knee, a fall or a sports collision can cause this pattern, sometimes alongside other knee injuries. Pain, swelling, stiffness or a feeling of instability can occur, but symptoms do not show the bone fragment’s position. Examination and imaging are needed to define the injury.

Until assessed, protect the knee from twisting, deep bending and impact. Use only the weight-bearing plan and support recommended by your clinician. Ice wrapped in cloth and elevation may help swelling if suitable for you. Treatment can involve a brace, structured rehabilitation or an operation when the fragment is displaced or the knee is unstable. A plan for [Knee Bracing](/treatments/non-surgical-orthopedics/knee-bracing/) or [Physiotherapy](/treatments/physiotherapy-and-rehabilitation/physiotherapy/) should be tailored after imaging.

Seek urgent assessment after a major knee injury if the knee is visibly deformed, rapidly swelling, locked or impossible to bear weight on. Get immediate help for a cold or pale foot, new numbness, weakness or severe calf pain. Worsening pain, fever or redness around a wound also needs prompt medical review. Do not return to sport while instability or an avulsion injury remains unassessed.

Ask where the bone fragment is, whether other ligaments or cartilage are involved, how much weight you may put through the leg, and which movements to avoid. Ask how progress will be checked and what findings would change non-surgical care to surgery.