ACL Injuries

What is it?
Like all other forms of ligaments, the anterior cruciate ligament (ACL) connects one bone (the femur or thigh bone) to another (the tibia or leg bone) and helps stabilize the joint. When torn, the ligament does not have significant healing capability and the individual is prone to episodes of instability and further damage to the joint.
Who gets it?
Injuries of the ACL of the knee can affect individuals of all ages and levels of activity.
What are the symptoms?
The ACL is most frequently injured in athletics, but certainly can be torn by any method that applies unusually high stresses to the knee joint. In sports, the injury typically occurs in association with sudden twisting or deceleration activities, and sometimes with a direct blow to the knee. As a rule, swelling develops shortly thereafter. Many athletic events occur in the evening, and patients may not notice the swelling until the following morning. In the event of an acute knee injury (which is marked by pain, followed shortly thereafter by swelling), there is approximately an 80% chance of a torn anterior cruciate ligament. The patient does not have to feel something pop or experience a sense of instability at the time of injury.
Diagnosis
The diagnosis of an ACL tear is made based upon a carefully performed history and physical examination. X-rays are usually normal, and magnetic resonance imaging (MRI) is usually not necessary to make this diagnosis.
Treatment
The treatment must be individualized and is based upon the age and activity level of the patient. In general, young individuals involved in agility sports are best treated with reconstructive surgery. Older individuals not participating in activities which require jumping, change of direction, and other agility activities can frequently be treated with strengthening of the muscles of the leg. The most important aspect of non-operative (conservative) treatment of patients with anterior cruciate ligament tears is the avoidance of high-risk activities.
At the time of surgery, the anterior cruciate ligament cannot be repaired. It is therefore reconstructed using an alternate material. The most frequently used materials are tissues from a strip of the patella tendon from the front of the knee, or hamstring tendons from the back of the knee. Most orthopaedic surgeons prefer using the patient’s own tissue, although some prefer donated cadaveric tissue from a tissue bank. Return to play typically takes six to nine months.