When a knee injury occurs to an athlete, the greatest concern is the stability of the knee. Although most injuries are minor, the one that worries us the most is a torn anterior cruciate ligament (ACL). The ACL provides the knee with rotational stability during pivoting or ballistic type sports activities. It is the major structure that protects the knee from damage. If the ACL is torn, the knee loses stability which causes additional damage to the surrounding structures, particularly the medial (inner) side of the knee. If recurrent episodes of instability occur and the knee suffers additional damage to the medial meniscus or articular cartilage, premature degeneration of the joint can occur. Arthritis can subsequently can result from an ACL tear.
To combat this premature degeneration, the last 25 years of orthopedic sports medicine has seen an explosion in techniques to reconstruct (replace) the ACL. Scientific evidence suggests, if you can protect the knee from additional episodes of instability, premature degeneration and arthritis can be delayed or prevented.
Since the torn ACL is in the center of the knee joint and experiences high forces of stress, it can not be simply repaired in a traditional sense. We cannot “sew it back together” like most other torn structures in the human body. In order to restore its proper function, the ACL has to be “replaced” (otherwise known as reconstruction).
In order to replace the ACL with a new ligament, we have to find a suitable substitute. Tendons have been found to be the easiest source for the new “grafted” ligament. We either use a tendon from the patient (autograft) or from another person (allograft or cadaveric tissue).
The most common sources of autograft are the patellar tendon and the hamstring tendon. Each graft has pro’s and con’s. In general, that patellar tendon autograft is felt to be the most reliable because it has the longest track record and results in predictable outcomes. It has the downside of increased postoperative pain and prolonged recovery. These two problems have led to the development of the hamstring autograft as an option. The hamstring graft (semitendinosis and gracilis tendons) has less pain, is more appealing cosmetically and clinically has equal outcomes in many studies. Some surgeons feel the autograft patellar tendon is the gold standard despite the studies that claim hamstrings and patellar tendons are equal.
My beliefs lie in the middle. I feel a hamstring graft is an excellent option and generally prefer it. For elite athletes who have access to therapy on a daily basis, I believe the patellar tendon is a better option. For the non-athlete who suffered an unusual injury resulting in an ACL tear, I utilize the allograft tendons (tibialis,patellar, peroneals). Allograft tissue has proven to be safe from accredited tissue banks. It results in a quicker return to activities of daily living and less post operative pain.
The latest development in ACL surgery is the use of two grafts in a double bundle configuration. Although this method is enticing because it reproduces “normal” anatomy, it is still in the developmental phases. I consider it another option in the armamentarium above. The surgery for two bundles is more complicated and more costly for a procedure that is already highly successful. The use of the double bundle ACL reconstruction will eventually either become mainstream or used for selected cases. Only time will tell.
If you have an ACL tear, and would like to discuss your options please contact me, or call my office at 313-277-6700.
