What Are the Causes of Anterior and Posterior Cruciate Ligament Injuries?
Injury to the cruciate ligaments is sometimes referred to as a "sprain."* The ACL is most often stretched or torn (or both) by a sudden twisting motion (for example, when the feet are planted one way and the knees are turned another).
The PCL is most often injured by a direct impact, such as in an automobile accident or football tackle.
Symptoms and Diagnosis
Injury to a cruciate ligament may not cause pain. Rather, the person may hear a popping sound, and the leg may buckle when he or she tries to stand on it. The doctor may perform several tests to see whether the parts of the knee stay in proper position when pressure is applied in different directions. A thorough examination is essential. An MRI is very accurate in detecting a complete tear, but arthroscopy may be the only reliable means of detecting a partial one.
Treatment
For an incomplete tear, the doctor may recommend that the patient begin an exercise program to strengthen surrounding muscles. The doctor may also prescribe a brace to protect the knee during activity. For a completely torn ACL in an active athlete and motivated person, the doctor is likely to recommend surgery. The surgeon may reattach the torn ends of the ligament or reconstruct the torn ligament by using a piece (graft) of healthy ligament from the patient (autograft) or from a cadaver (allograft). Although synthetic ligaments have been tried in experiments, the results have not been as good as with human tissue. 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 that may involve using special exercise equipment at a rehabilitation or sports center. Successful surgery and rehabilitation will allow the patient to return to a normal lifestyle.
What Is the Most Common Cause of Medial and Lateral Collateral Ligament Injuries?
The MCL is more easily injured than the LCL. The cause is most often a blow to the outer side of the knee that stretches and tears the ligament on the inner side of the knee. Such blows frequently occur in contact sports like football or hockey.
Symptoms and Diagnosis
When injury to the MCL occurs, a person may feel a pop and the knee may buckle sideways. Pain and swelling are common. A thorough examination is needed to determine the kind and extent of the injury. To diagnose a collateral ligament injury, the doctor exerts pressure on the side of the knee to determine the degree of pain and the looseness of the joint. An MRI is helpful in diagnosing injuries to these ligaments.
Treatment
Most sprains of the collateral ligaments will heal if the patient follows a prescribed exercise program. In addition to exercise, the doctor may recommend ice packs to reduce pain and swelling and a small sleeve-type brace to protect and stabilize the knee. A sprain may take 2 to 4 weeks to heal. A severely sprained or torn collateral ligament may be accompanied by a torn ACL, which usually requires surgical repair.
