The ACL is most often partially or fully torn (or both) by a sudden twisting motion (for example, when the foot is planted one way and the knee is turned another, such as skiing, soccer or basketball).
The PCL is most often injured by a direct impact, such as in an automobile accident or stepping into a hole.
- Pain and immediate swelling
- Difficulty straightening and bending the knee
- Loud popping sound when the injury happened
- Instability or buckling of the knee, especially when pivoting
For an incomplete tear, the doctor may recommend rest and immobilizing the knee until pain is controlled, then physical therapy to strengthen surrounding muscles. The doctor may also prescribe an ACL brace to protect the knee during activity.
For a completely torn ACL in an active athlete or motivated person, the doctor is likely to recommend surgery. This is to prevent further injury to the knee and allow the patient to return to sports that require pivoting. The surgeon will reconstruct the torn ligament by using a piece of healthy ligament from the patient (autograft) or from a cadaver (allograft).
One of the most important elements in a patient’s successful recovery after cruciate ligament surgery is a 4- to 6-month exercise and rehabilitation program.