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Knee Ligament Reconstruction

One of the more common and devastating athletic injuries evaluated by the sports physician is the anterior cruciate ligament tear in the knee. This is seen across a wide spectrum of both contact and non-contact sports participants. A large number of surgical procedures have been developed over the past several decades for treatment of this condition.

Once torn, the anterior cruciate ligament ends are usually shredded and do not have the capacity to regenerate or heal. Attempts to suture the torn ends together are doomed to fail. Normally, the torn ligament ends are absorbed and are not evident a few months after injury. Athletes with a torn anterior cruciate ligament usually develop an unstable or "trick" knee. To treat persistent instability, a variety of tendon transfers, muscle advancements, and non-anatomic ligament reconstructions have been attempted in the past. Unfortunately, most previous attempts have done very poorly and, in many cases, have actually made instability worse causing early post-traumatic arthritis of the knee.

Over the last fifteen years it has been realized that if a surgical procedure is going to be successful it must restore a reconstructed ligament to the site of the original anterior cruciate ligament. This is known as an anatomic reconstruction. Once this was realized, a variety of attempts were made to utilize synthetic graft materials such as dacron or gortex. Unfortunately, these materials do not attach well to the human body and normally will fail after a short period of time. It is not a synthetic braided material , but living tissue to replace the anterior cruciate ligament.

A decade ago there was considerable interest in transplanting donor ligament or tendon structures from cadaver specimens. Actual cruciate ligaments and tendons were transplanted by an arthroscopic procedure into the injured knee to the site of the anterior cruciate ligament attachments. This tissue, while actually dead, is re-vascularized by the body and a new ligament will grow across the reconstruction. The transplant or allograft tissue acts as a ladder for the new healthy tissue to grow over a period of approximately six months. The use of allograft material allows for the surgical reconstruction to be performed through small arthroscopic incisions. Unfortunately, there has been considerable concern in the medical and athletic community about the possibility of virus transmissions, such as HIV or hepatitis C with this tissue. Obviously, nobody wants to contact a severe, potentially fatal, viral infection in an attempt to regain a stable knee.

At the present time, the standard technique to reconstruct the anterior cruciate ligament utilizes what is known as autologous tendon material. This normally represents a strip of quadriceps or hamstring tendon from the patient's own leg that is harvested leaving the bulk of the muscle and tendon fibers in place. Surgical drill holes are placed across the femur and tibia, exiting inside the knee at the site of the anterior cruciate ligament origin and insertion sites. The tendon strip is then placed through both bone tunnels and fixed at both ends with staples or screws. Normal healing and vascular ingrowth will then occur.

Within six to eight weeks the tendon graft has been incorporated and begins to remodel and form a new ligament. Care must be taken to avoid stressing the ligament during this time frame, as there is a possibility of the reconstruction rupturing or pulling loose. For the most part, the anterior cruciate ligament surgery is performed arthroscopically and requires an overnight stay at the hospital. Immediate protected weight-bearing is allowed, but with a hinged knee brace and crutches for support. Normally, the crutches are discontinued in four to six weeks. Rehabilitation is continued two to three times a week for three to four months prior to allowing the athlete to return to running activities at four months and usually to contact activities by six months. Proper surgical technique and proper rehabilitation normally allow the athlete to return to their pre-injury level of athletic participation.