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Anterior Cruciate Ligament (ACL) Injury

Alternative names: ACL Damage, Torn or Ruptured ACL

What is the anterior cruciate ligament?

Four ligaments connect the thighbone (femur) to the shinbone (tibia). The ACL is in the center of the knee and keeps the femur from rotating too far, and from moving too far forward over the tibia.

What are the signs of an ACL injury?

A patient might hear a popping sound, and won't necessarily feel any pain. The leg may buckle when the patient tries to stand on it. The knee might swell up after the injury.

What causes an ACL injury?

The injury occurs most often if the feet are planted in one direction and the knees are twisted in another. Tears of the anterior cruciate ligament (ACL) of the knee have become an increasingly more common and recognized problem over the past 15 years.

How does a doctor tell if a patient has an ACL injury?

Your doctor will try to move your knee in different directions to see how loose it is and whether it stays in its proper position. An MRI is very accurate in detecting a tear, but looking at your knee internally through a scope may be the only way to tell if it is partially torn.

How is an ACL injury treated?

Advances in diagnostic and surgical techniques have allowed sports medicine physicians and orthopaedic surgeons to more successfully treat patients who have torn ACLs. Our approach has been to individualize the treatment of patients with ACL tears. Some patients with ACL tears have very little difficulty using their knees normally while others with the same degree of injury frequently have limitations in their activity. There are many critically important variables to consider (such as age, athleticism, expectations) in patients that have torn an ACL. The surgeon must tailor the treatment to each person's individual circumstances.

The most fundamental problem following a tear of the ACL (once one has recovered from the initial injury) is that the knee is "loose." The normal ACL restrains the knee in a very small range and this critical restraint is lost following a tear. Some patients will not place high demands on their knee following an ACL tear and are willing to avoid sports such as basketball and soccer and will be happy with nonoperative treatment of their injury. Patients who are active and unwilling to forego participation in activities which place significant stress on their knee will choose to have reconstruction of the anterior cruciate ligament.

Non-surgical treatment

For some patients, the doctor may recommend begining an exercise program to strengthen surrounding muscles. The doctor may also prescribe a brace to protect the knee during activity.

Surgical treatment

Various techniques and grafts are used to reconstruct the ACL. We use an arthroscopic technique and recommend one of the three most commonly used grafts. The patellar tendon (bone-tendon-bone) graft, the hamstring tendon graft, and allograft (donor tissue) all have their various advantages and disadvantages. At this point, there is no strong evidence to suggest that one of these grafts is better than the other. However, for certain patients, a particular graft may be better suited for that person to avoid the potential disadvantages that another type of graft may cause.

A specific post-operative rehabilitation program, based on the graft type selected, begins within one or two days of the surgery. Goals to reach in the postoperative recovery process are full range of motion by four weeks, jogging by three months, and return to sports by six months.

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