The anterior cruciate ligament, often called the ACL, has an integral role in stabilizing the knee joint. According to the Mayo Clinic, ACL injuries commonly occur in athletes and often require surgery to correct. After surgery, most people can resume their normal activity, including athletics, within about six months.
Normal ACL
The knee joint is like a hinge that allows the shin to move behind the thigh. Four ligaments made of tough fibrous tissue connect the thigh bone (femur) to the shin bone (tibia) through the kneecap. In the middle of the kneecap, the ACL crosses over the posterior cruciate ligament, forming an “X” shape. The ACL prevents side-to-side rotation of the knee, and prevents the tibia from slipping in front of the femur.
ACL Injury
Sports that involve quick starts and stops, twisting, or extraordinary force on the knees take a toll on the ACL. When the ACL tears, the knee feels “loose,” as if it could twist to the side, or unstable and unable to bear weight. At the time of injury, the tear can sometimes be heard as a popping sound. Severe pain and swelling follow the injury.
Women and ACL Tears
Women are more likely than men to tear an ACL, even among those who play the same sports, because women’s quadriceps in the front of the thighs tend to be stronger than the hamstrings in the back of the thighs. Because the hamstrings help keep the shins correctly aligned behind the femur, weaker hamstrings put greater stress on the ACL and can predispose to a tear.
Choosing Surgery
Tears of the ACL in adults usually do not heal on their own, says Medline. Although some people with a torn ACL forgo surgery and function just fine, most people with an un-repaired ACL tear feel an uncomfortable sensation of looseness in the knee and worry that it will collapse. For people with more severe injuries or for athletes who want to return to their sport, doctors usually recommend surgery to replace the ACL. Medline says that un-repaired torn ACLs can lead to an early onset of arthritis in the injured knee. However, even after a successful surgery to repair a torn ACL, the Mayo Clinic says that about 50 percent of patients develop arthritis in the knee 10 to 20 years later.
Surgical Procedure
The surgeon cannot sew back together a torn ACL, so the surgery involves replacing the ACL with a tendon from the patient’s leg or from a donor. In this outpatient procedure, the surgeon makes one or two small incisions in the knee to accommodate special instruments and a camera to guide the attachment of the tendon to the femur and tibia.
