What is the ACL?

The ACL, or anterior cruciate ligament, is a rope-like structure in the middle of the knee which helps to stabilize and support the knee. With activity, especially high-speed cutting and pivoting, the ACL acts as a restraint to excessive translation and rotation in the knee. In some cases, usually during athletic activity, the stress across the ligament is too great, and the ACL ruptures. Tears of the anterior cruciate ligament are quite common, with between 70,000 to 80,000 reported each year in the United States. In many patients who have torn their ACL, subsequent instability develops leading to occasional episodes of giving way or buckling. Not all patients who tear their ACL require surgery, however. In some cases, the patient’s knee will remain stable despite absence of the ligament. In most high level athletes, though, a ligament reconstruction is advised to provide the needed stability required to protect the knee?.

What do I do if I think I have torn my ACL?

Immediately after the injury, the patient is advised to use crutches, limit weight-bearing, ice (20 minutes every 2-3 hours), and take an anti-inflammatory to reduce pain. An appointment with an orthopaedist should be scheduled, and x-rays and an MRI will be ordered if appropriate. ?

Can the ACL heal by itself?

Many ligaments can heal by themselves after an injury. The ACL, however, is unique in that it seldom, if ever, heals after a complete tear. There are anatomical and biochemical factors which explain this peculiarity. For these reasons, surgical reconstruction requires the grafting of replacement tissue in place of the torn ligament.

How long does the surgery take?

The surgery to reconstruct an ACL takes between 60-90 minutes depending on whether there is associated damage in the knee and what type of graft is used.

What are my options for graft tissue?

There are three common graft choices for ACL reconstruction: patellar tendon, hamstring tendon or allograft (cadaver) tissue. Patellar tendon is the preferred graft for many orthopaedic surgeons and is usually Dr. Diaz’s graft of choice. Use of patellar tendon allows solid bone to bone fixation and healing. Hamstring tendon and Allograft have become a second “gold standard” for ACL reconstruction over the last decade as fixation techniques have evolved. Allografts were typically used for older patients or those who have already had previous ACL reconstruction which failed (revision surgery). Increasingly, however, allograft is being used in younger patients in primary reconstructions. There are other graft option, such as quadriceps, which are used less commonly.

Which is better, patellar tendon or hamstrings?

This is a common source of debate. All graft choices have distinct advantages and disadvantages. “In my opinion, patellar tendon provides a very stable construct over the long term, allowing reliable fixation and providing a consistent source of robust graft tissue,” says Dr. Diaz. There may be discomfort with kneeling which typically resolves by one year. The scar in the front of the knee is slightly larger with patellar tendon graft than with hamstrings, and this may be an issue in female patients. The principal disadvantage of a hamstring graft is loss of flexion (bending) strength past 90 degrees. When using hamstring graft, two of the hamstring tendons are sacrificed for the graft. This is in contrast to patellar tendon graft where only the central third of the tendon is harvested. It is important to keep in mind that both graft choices are essentially equivalent with respect to outcomes data over the long term. Dr. Diaz explains, “In certain situations, one graft may be preferable over another, however, it is best for the surgeon to use the graft with which he is most comfortable, and which he feels best suits your needs.”

When does rehabilitation start?

The patient returns for follow-up with Dr. Diaz two days after surgery. The knee is checked and bandages are changed. Formal therapy is initiated on the fifth day after surgery. The initial goals of therapy include quadriceps activation, minimizing swelling and achieving full extension (getting the knee completely straight).

When can I return to playing my sport?

The rate limiting step in return to sport is the conversion of the graft tissue to a viable ligament. Once complete the patient is allowed full return to sport provided all swelling has resolved and full motion and near-full strength have been regained. This process is complete by 5-6 months. Nonetheless, it is important to realize that not all patients heal at the same speed. “I have had some patients return to normal level of play by 4 months, and others that require 9-12 months. These athletes need to work hard in therapy and on their own to maximize their recovery. The best outcomes are the product of a well-performed surgery and a rigorous and thoughtful rehab protocol,” says Dr. Diaz.

How is the surgery performed?

ACL reconstruction is performed using arthroscopic techniques, in which a combination of fiber optics, small incisions, and small instruments are used. (A somewhat larger incision is needed to obtain the tissue graft.) Patients undergoing ACL reconstruction are usually given a femoral nerve block, which helps decrease pain for several hours after surgery, and a general anesthetic. An overnight stay in the hospital is not necessary.?The following is video from an arthroscopic ACL reconstruction using patellar tendon graft. The graft was harvested prior to the arthroscopic portion of the case.