PCL (posterior cruciate ligament) injuries usually result from dashboard impacts or hyperflexion. Mild grade I/II tears heal with bracing; grade III tears or combined injuries need arthroscopic reconstruction.
How does a PCL tear happen?
The classic mechanism is a direct blow to the front of a bent knee — common in road traffic accidents (the dashboard injury).
Sports injuries with a hyperflexion or hyperextension force are the second most common cause.
Diagnosis
Posterior sag sign on examination plus a confirmatory MRI gives the diagnosis. Stress X-rays quantify the severity.
Treatment
Isolated grade I and II PCL tears do well with a 6–12 week PCL brace and progressive quad strengthening.
Grade III tears, multi-ligament injuries, or persistent instability need arthroscopic PCL reconstruction with a tendon graft.