The PCL is the ligament that prevents the tibia from sliding too far backwards
The PCL helps to maintain the tibia in position below the femur
The most common mechanism of injury of the PCL is the so-called "dashboard injury." This occurs when the knee is bent, and an object forcefully strikes the shin backwards
The other common mechanism of injury is a sports injury when an athlete falls on the front of their knee. In this injury, the knee is hyperflexed (bent all the way back), with the foot held pointing downwards
Symptoms of a PCL tear are very similar too an ACL rupture; knee pain, swelling, and decreased motion are common with both injuries
PCL tears are graded by the severity of injury, grade I through grade III. The grade is determined by the extent of laxity measured during your examination. In general, grading of the injury corresponds to the following:
Grade I: Partial tears of the PCL.
Grade II: Isolated, complete tear to the PCL.
Grade III: Tear of the PCL with other associated ligament injury.