Anterior Cruciate Ligament (ACL) Tear
Knee injuries often occur among active teens, especially athletes, and a torn anterior cruciate ligament (ACL) — a ligament that helps give the knee its stability — is a common knee injury. An anterior cruciate ligament, or ACL, injury is a tear in one of the knee ligments that joins the upper leg bone with the lower leg bone. Injuries range from mild, such as a small tear, to severe, such as when the ligament tears completely or when the ligament and part of the bone separate from the rest of the bone. Symptoms of an acute ACL tear include:
1. Feeling or hearing a pop in the knee at the time of injury.
2. Pain on the outside and back of the knee.
3. The knee swelling within the first few hours of the injury. This may be a sign of bleeding inside the knee joint. Swelling that occurs suddenly is usually a sign of a serious knee injury.
4. Limited knee movement because of pain or swelling or both.
5. The knee feeling unstable, buckling, or giving out.
After an acute injury, you will probably have to stop whatever you are doing because of the pain, but you may be able to walk. It is estimated that 70 percent of ACL injuries occur through non-contact mechanisms while 30 percent result from direct contact with another player or object. The mechanism of injury is often associated with deceleration coupled with cutting, pivoting or sidestepping maneuvers, awkward landings or "out of control" plays.
Several studies have shown that female athletes have a higher incidence of ACL injury than male athletes in certain sports. It has been proposed that this is due to differences in physical conditioning, muscular strength, and neuromuscular control. Other hypothesized causes of this gender-related difference in ACL injury rates include pelvis and lower extremity (leg) alignment, increased ligamentous laxity, and the effects of estrogen on ligament properties. Immediately after the injury, patients usually experience pain and swelling and the knee feels unstable. Within a few hours after a new ACL injury, patients often have a large amount of knee swelling, a loss of full range of motion, pain or tenderness along the joint line and discomfort while walking.
Surgical treatment is usually advised in dealing with combined injuries (ACL tears in combination with other injuries in the knee). However, deciding against surgery is reasonable for select patients. Nonsurgical management of isolated ACL tears is likely to be successful or may be indicated in patients:
1. With partial tears and no instability symptoms
2. With complete tears and no symptoms of knee instability during low-demand sports who are willing to give up high-demand sports
3. Who do light manual work or live sedentary lifestyles
4. Whose growth plates are still open (children)
In nonsurgical treatment, progressive physical therapy and rehabilitation can restore the knee to a condition close to its pre-injury state and educate the patient on how to prevent instability. This may be supplemented with the use of a hinged knee brace. However, many people who choose not to have surgery may experience secondary injury to the knee due to repetitive instability episodes.