ACL Injuries

The ACL (anterior cruciate ligament) is in the knee. The knee is the largest and most complex joint in your body. It depends on four ligaments and other muscles and tendons to function properly. The ACL connects the front part of the shin bone to the back part of the thigh bone and keeps the thigh bone from sliding forward.

Causes of Injuries
A direct blow to the knee, which commonly happens in football or a fall when skiing, is one of the most common causes of ACL injuries. The knee is forced into an abnormal position and one or more ligaments are torn. However, most ACL tears actually happen without contact between the knee and another object. Such non-contact injuries happen when the athlete is planting the foot and cutting, landing on a straight leg, or making an abrupt stop. These movements are common in basketball, football, volleyball and soccer.

Symptoms
In many cases, when the ACL is torn, you will feel the knee give way with an audible "pop." You may feel a moderate amount of pain, making it impossible to continue activity. Over the next several hours, the knee becomes very swollen and walking becomes difficult. The swelling and pain usually are the worst for the first two days and then begin to subside.

Diagnosis
ACL tears usually cause enough discomfort to cause the injured person to seek medical attention. The physician will examine the knee, and, in most cases, be able to identify which ligaments are injured. However, there may also be injuries to the joint surface that are more difficult to diagnose. In addition, swelling may sometimes make it difficult to diagnose a tear. Further evaluation with an MRI or arthroscope may be necessary to completely evaluate the injury.

Treatment
A physician will consider several factors to determine if you are a candidate for surgery or non-surgical treatment, such as your activity level and expectations, other associated injuries, and condition of your knee.

Rehabilitation of the knee is a non-surgical option for some patients. Exercises help restore full range of motion and build strength. A return to sports with or without a brace is allowed only after leg strength, balance and coordination have returned to near normal.

The overall success rate for ACL surgery is very good. Many studies have shown that over 90 percent of patients are able to return to sports and workplace activities without symptoms of knee instability. Although some patients do complain of stiffness and pain after surgery, these problems have been minimized by current surgical techniques and aggressive rehabilitation.

Source: American Orthopaedic Society for Sports Medicine