ACL Injuries: Who, How, and why?
“Doc, I fell and twisted my knee. I heard a pop. It hurt briefly. When I stood up, the knee felt as if it was not underneath me, and the knee gave way. It swelled up by the next day and ever since feels as though it would pop out when I twist or even cross the street quickly.” In almost all cases the above complaints occur due to an injury to the ACL (Anterior Crucial Ligament) of the knee. The ACL is a very important ligament in the knee that controls the pivoting motion of the knee. This joint guides the femur and tibia through a regular range of motion. It is the most common and serious of injury sustained to the knee (Duffy, f9). How this injury happens, who is most susceptible, and how it is treated are a few questions athletes are becoming heavily concerned with.
ACL injuries account for over sixty percent of all knee injuries and those numbers are growing every year (Lamb 145). The major cause of injury to the ACL is sports related. The types of sports, which have been associated with ACL tears, are numerous. Those sports requiring the foot to be planted and the body to change direction rapidly (such as basketball) carry a high incidence of injury. Football, of course, is frequently the source of an ACL tear. Football combines the activity of planting the foot and rapidly changing direction plus the threat of bodily contact.
One group that has a high occurrence of ACL injuries is female athletes. This is in part due to the rise in women’s athletics, but studies have shown that female athletes are more likely to suffer this injury when compared to their male counterparts. The exact reason is unknown, but there are several theories. One theory is that women’s athletics are becoming more intense and this is putting female athletes at higher risk (Robertson Personal Interview). The women’s sports are trying to catch up to the intensity men’s sports are now played and women are suffering injuries trying to get to that level of competition. Other reasons thought to be contributing to women’s higher risk are the anatomy of their knee differing from that of a man’s (Lamb 142). Tests have shown that the female ligament is weaker than males due to the effects of the female hormone estrogen. The distribution of muscle strength may also be a factor. With the help of the hamstring and quadriceps (back and front of leg) the knee joint is stabilized. If those muscles are not of adequate strength the knee may bear more stress than it is capable of. “On average the hamstring should be sixty to seventy percent the strength of the quadriceps. In most women this number drops to forty-five to fifty percent” (Duffy, f9). Women also use these two muscles differently; women rely more on the quadriceps than the hamstring. The hamstring protects the ACL more than the quadriceps so the imbalance is considered a risk factor in knee injuries.
One other group in high risk of knee injury is the “weekend warriors”. These are the people that are not active on a regular basis. They may take part in an athletic activity once in a while, but not often enough to be in the shape needed to compete at high levels. When injuries occur in this group it is usually because these “weekend warriors” push their bodies to a limit they are not used to reaching. “Exercise and making one’s body work hard is good if it can be done often, but rare cases of exertion tend to just be added stress to the body and injuries are prone to happen”(Robertson Personal Interview). The strength of the legs and joints is very important like mentioned above to avoid injury, but this group of people never takes the time to condition these muscles and in many cases, they are provoking an accident to happen.
Treatment of ACL injuries varies greatly from case to case. Initial treatment for ACL injury includes crutches and rest until the swelling resolves. The knee joint may need to have blood removed from the joint. “Once, the initial pain and swelling begins to resolve physical therapy will probably be initiated to regain as much of the normal range of motion as possible” (http//: sportssci.org). One of the problems that tearing the ACL causes, is that the nerve endings in the ligament are torn as well. These nerves are there to give the brain information about where the body is in 3D space. A good physical therapy program will help re-train these nerves as they repair themselves, and will strengthen certain muscles that will take over some of the functions of stabilizing the knee joint from the loss of the ACL.
To help replace the stability of the knee due to the loss of the ACL, an ACL brace may be suggested. These braces are fairly effective at preventing the knee from giving way during strenuous activity. “A certified orthotist , a physical therapist, or a physician must fit most of these braces” (http//: sportssci.org). These are not the types you can buy at the drugstore. Most orthopedists will recommend wearing a brace for at least one year after a reconstruction, so even if you decide to have surgery, a brace is a good investment. If a brace and/or rehab program does not control the symptoms of instability, then ACL surgery will be suggested. Most surgeons now favor reconstruction of the ACL using a piece of tendon or ligament to replace the torn ACL. Today, this surgery is most often done using the arthroscope. Incisions are usually still required around the knee, but the joint itself is not opened. Most patients can expect at least one night in the hospital, although more and more surgeries are being done outpatient, where you leave the hospital the same day.
In the typical surgical reconstruction, the torn ends of the ACL must first be removed. Once this has been done, the type of graft that will be used is determined. One of the most common tendons used for the graft material is the patellar tendon. This tendon connects the kneecap to the lower leg bone. Another very common graft that is used is to combine two of the hamstring muscles to tendons that attach to the tibia just below the knee joint. Studies have shown that these two tendons can be removed without really affecting the strength of the leg.
Other types of grafts that are used sometimes come from tissues harvested from tissue and organ donors. Tissues are taken at time of death and checked for infection, then sterilized for later use. This procedure is best because nothing has to be rearranged in the patient’s body.
After surgery, a physical therapist will be contacted to begin your rehabilitation program. You will probably be involved in some type of rehabilitation for six months after surgery to ensure the best result from you ACL reconstruction. The first six weeks following surgery expect to see the physical therapist about three times a week. Following the initial period, you may be placed on a home program and monitored by the therapist.
An ACL injury can greatly affect one’s life. Most people afflicted by this injury are very active and are forced to drastically change their lifestyles while recovering. After re-constructive surgery and an adequate and successful rehabilitation program, the patient should expect a full recovery and be able to compete at the same level they had before the injury. With proper precautionary measures ACL injuries are avoidable, but completely eliminating them is impossible. As long as people choose active lifestyles, ACL injuries are a threat athletes will just have to live with.