ACL Injury and Repair Options
Kevin G. Shea, M.D.ANTERIOR CRUCIATE LIGAMENT
The Anterior Cruciate Ligament, or 'ACL', is one of the most important ligaments for the knee. It is a primary knee stabilizer, which limits the motion of the knee joint in the front to back plane. The ACL also provides some rotational stability to the knee joint. Many high profile athletes have injuries to this structure. This injury is relatively common in athletes that compete in 'high-demand' knee sports, such as football, basketball, volleyball, skiing, soccer, etc. Sports that require rapid changes in direction place very significant demands on the knee. Athletes with this injury may experience 'instability or giving out' episodes, if they try to return to high demand sports. Although these injuries can occur during collisions with another athlete, these injuries may occur without contact with another athlete. The ACL can be injured when the athlete changes directions, or comes down from a jump. These 'non-contact' injuries are especially common in female athletes. In general, adult female athletes are much more likely to tear their ACL than male athletes. Recent research conducted in the Treasure Valley has also shown that young female soccer players have higher rates of ACL injury, starting at age 12(1).
(1) American Academy of Orthopaedic Surgeons Annual Meeting, 2001 Age related risk factors for ACL injury in pediatric and adolescent soccer players - differences between male and females. Shea KG, Wang J, Pfeiffer R.
If I have torn my ACL, do I need to have it repaired?
Some people who sustain this injury do not necessarily need a surgical reconstruction, as they can function well if they participate in an appropriate rehabilitation program. In patients that place high demands on their knees, we usually recommend ACL reconstruction, as these individuals may have problems with their knees in the future without undergoing an ACL reconstruction. In general terms, younger individuals place higher demands on their knee, and are more likely to have problems with their knee in the future. These problems include feelings of 'instability', 'giving way' episodes, as well as future injuries such as meniscus tears, or articular cartilage damage. Although younger patients tend to be more active and place high demands on their knee, many people remain physically active and participate in high demand activities throughout their lives. Many types of work place high demands on the knee, and surgery may be required to stabilize the knee for a high demand work environment. Many older patients will also develop symptoms after an ACL injury, and require an ACL reconstruction.
If you and your surgeon decide that an ACL reconstruction is an option to treat your knee injury, your physician will discuss the details of the procedure, as well as the rehabilitation after surgery. Rehabilitation after surgery is a critical component in your recover, and you must make a serious commitment to your rehab. This will include extensive therapy under the supervision of your surgeon and a therapist. A commitment of one year is very important, and your will be followed closely during your rehab. Your rehab program will consist of several modalities, which are designed to obtain the maximal recovery, and to allow you to return to sports and other activities.
The surgical reconstruction involves using a tendon graft to repair your ACL. This graft is attached to your thigh bone (femur), and your shin bone (tibia), by placing the graft through drill holes in the bone. The tendon can be obtained from your own knee, or a cadaver. In essence, there is no perfect ACL graft, as each type of graft choice has certain advantages and disadvantages. These factors need to be considered for all patients, and different choices exist for individual patients. In many cases, a patient will have several choices of graft type, and the patient and their surgeon can make the choice together. For ACL reconstruction, several graft choices exist, and these will be listed below.
1. BONE-TENDON-BONE: This graft choice has a 20-year history of successful use, and has been one of the most common graft choices for ACL reconstruction. This graft is harvested from the front of your knee. A portion of bone is taken from your knee cap and the tibia, with a section of tendon in between these two bone sections. In most patients, this graft is of adequate size and quality. Some patients have a small knee tendon, and this may not be the best choice. In recent years, several studies have shown that the chronic anterior knee pain is a problem in some patients after surgery using the bone-tendon-bone graft. Because of this, many ACL surgeons have started using other grafts, to reduce the incidence of anterior knee pain. Many patients are concerned about this potential for anterior knee pain, and they would prefer that other graft sources be used. This graft still remains a good choice, and the results with this tissue are consistently good. In many cases, the anterior knee pain is a minor problem, and the incidence of this condition can be influenced by proper physical therapy, exercise, and conditioning. Some patients that perform work tasks while kneeling complain of additional pain with this procedure.
2. HAMSTRING TENDON: In recent years, more surgeons have been using this graft, because the incidence of anterior knee pain with this graft is minimal. Like any new surgical technique, there is a learning curve involved with the new procedure. Some surgeons find that this technique is more demanding technically, although some surgeons are equally comfortable with either hamstring grafts or bone-tendon-bone grafts. In this technique, one or two tendons are harvested from the back of the knee and thigh region. One hamstring tendon (semi-tendinosis muscle) and one adductor tendon (gracilis muscle) are harvested from their attachment point on the crest of the tibia, just below the knee. These grafts are then configured into a tendon. Some surgeons have suggested that it is more difficult to obtain secure fixation of this graft to the knee, although recent techniques have demonstrated that this graft can produce a good ACL reconstruction with excellent clinical results. In general, the rehabilitation is easier with this graft, as the pain from harvesting the graft is less intense. Similar to patients that use the bone-tendon-bone grafts, patients will need to work on extensive rehabilitation, with an emphasis upon weight lifting to recover strength after surgery.
3. QUADRICEPS TENDON: Many surgeons in Europe use this graft, as they believe that it has some of the advantages of the bone-tendon-bone graft, without having the problems with anterior knee pain. In this case, a portion of the quadriceps tendon is taken with a portion of bone from the top or proximal part of the kneecap. This graft may be used as a revision graft as well, in cases where the athlete has torn the ACL for a second time.
4. ALLOGRAFTS: These grafts are obtained from cadavers, and may consist of patellar bone-tendon-bone, Achilles tendon grafts, or tendons. These grafts are tested extensively for most known types of infectious disease, and the chance of acquiring an infection from these grafts is very small. The potential for acquiring an infection still exists, and patients need to be award of this. One significant advantage of this graft is the lack of pain and weakness that occurs in a patient after harvesting their own tissue for a graft. The surgery takes less time, the incisions are smaller, and the rehabilitation is much easier and less painful for the patient. In patients who have sustained another ACL injury, or in patients that are older, this may be a reasonable choice. The number of studies with long-term follow-up is more limited, and there is the potential for problems with these grafts in the future. Many surgeons will use these grafts in patients with a second injury, or in patients that have sustained a serious injury, which requires multiple ligament repair.
5. SYNTHETIC LIGAMENTS: Different types of polymers (Dacron , Gore-Tex , etc.) have been tried in the past. Many of these tissue substitutes have not stood up over time, and most are no longer available for clinical use. For most patients, we usually recommend using your tissue as the first choice. Because the tissue is from your own knee, there are no risks of infection or graft rejection. In some cases, patients will prefer to use a graft from a cadaver. These issues will be discussed between you and your surgeon.