The PCL is the ligament that prevents the tibia (shin bone) from sliding too far backward. Along with the ACL which keeps the tibia from sliding too far forward, the PCL helps to maintain the tibia in a position below the femur (thigh bone).
Like most ligament tears, a torn PCL is typically observed with swelling and pain. Usually the swelling is located in the back of the knee, and in some cases there may be bruising. Some patients may have difficulty walking, and in severe cases, the knee may feel unstable like it's "giving out".
For a very minor sprain, which would be called a grade 1 PCL tear, athletes may be able to return back to competition within 2 or 3 weeks. ... For a grade 2 PCL tear, where there may be more instability of the knee, it may take up to 6 weeks for a sufficient recovery without surgery.
Although it is larger and stronger than the ACL, the PCL can be torn. PCL tears make up less than 20% of injuries to knee ligaments.