The anterior cruciate ligament (ACL) is one of the most common knee injuries seen in orthopedic surgery. This injury occurs in basketball, football, soccer as well as other sports. It can also occur at work from a twisting, turning type of injury.
The knee has four main ligaments: the medial and lateral collateral ligaments and the anterior and posterior cruciate ligaments. The collateral ligaments are outside the knee capsule and control side to side movement. The cruciate ligaments are inside the joint and control forward and backward motion. All four ligaments provide stability to the knee.
Ligaments are graded by their severity: 1, 2 and 3 being the most severe.
Grade 1: mild stretching of the ligament.
Grade 2: partial tearing of the ligament.
Grade 3: complete tearing of the ligament.
When a ligament is injured a patient may actually hear a "pop" in the knee followed by pain and later swelling. If the ligament is severely injured there will be instability. This will feel like the knee wants to give out. Patients will usually not be able to move their knee fully and will have difficulty walking.
The doctor will take a history and examine the knee at the visit. The knee will be checked for its range of motion as well as its stability. The non-injured knee will also be examined to provide comparison. Xrays may be ordered, but they often are of little help with a torn ligament since it will not show up on regular films. An MRI is the gold standard for visualizing ligament tears as well as looking at the meniscus and cartilage surfaces.
Treatment for ACL injuries is either non-operative versus surgery. Non-operative treatment usually entails rest, crutches, bracing and physical therapy. This is usually recommended for those patients with a very low activity level.
Surgery involves reconstructing or making a new ACL. The ligament cannot be sutured back to itself due to the blood supply being disrupted. ACL reconstructions are done using autograft, the patient's own tendon or allograft, using cadaver tendon. The decision to use which type of graft is made with the surgeon and the patient. Either way the surgery is done arthroscopically with limited incisions. The surgery is done as an outpatient and most patients are able to put some weight on the leg right away.
Physical therapy is just as important whether or not surgery is performed. Initially the goal of therapy is to regain knee motion and decrease swelling. As time progresses it is important to rebuild knee strength. This will usually take at least 6 months post injury/surgery. An ACL brace may be used to help protect the new ligament. Most patients who undergo ACL reconstruction are able to return to all sports after completing therapy.