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Knee Questions: Knee Arthritis Total Knee Replacement Oxford Knee Replacement ACL Reconstruction Patello Femoral Pain Cartilage Injury Meniscus Injury back |
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| _________________________________________________________________ What is the ACL? The anterior cruciate ligament (ACL) is one of the four stablizing ligaments of the knee. It prevents abnormal anterior displacement and rotation of the lower leg with respect to the thigh. The ACL is located in the center of the knee joint and runs from the femur (thigh bone) to the tibia (shin bone), through the center of the knee. How is the ACL injured? The ACL may be injured with excessive pivoting or twisting of the knee as well as hyperextension, hyper flexion or lateral trauma to the knee. Usually the tearing of the ACL occurs with a sudden direction change or when a deceleration force crosses the knee. The patient often feels or hears a popping sensation, has the rapid onset of swelling, and develops a buckling sensation in the knee when attempting to change direction. How is an ACL tear diagnosed? When the ACL is torn, the patient may hear or feel a "pop" in the knee, followed by swelling and difficulty continuing the sport. The patient may have a hard time walking and may also feel a sense of instability. An ACL tear is best diagnosed by a physical examination by an orthopedist. An MRI (magnetic resonance imaging) may be obtained to confirm an ACL tear as well as to identify injury to other knee structures. What is the outcome of an ACL injury? Regardless of whether the ACL is stretched, partially torn or completely ruptured, it no longer provides normal stability to the knee. Patients, who do not participate in pivoting sports or do not require knee stability for daily chores and work, may attempt a rehabilitation program to strengthen leg muscles and also wear a brace for pivoting activities. Approximately one-third of patients that injure their ACL will experience relatively few problems and lead a fairly normal lifestyle. Another one-third will have problems with their knee during various athletic activities. These people could live with their knee satisfactorily if they are willing to give up those activities that give them problems. The remaining one-third of patients will have problems with their knee even with simple activities of daily living such as stepping off a curb or changing direction while walking. The decision to undergo an ACL reconstruction is highly individualized. Patients who should consider undergoing an ACLreconstruction are those who plan to continue an active lifestyle which places demands on the injured knee. A torn ACL makes the knee vulnerable to re-injury because it is not stable in certain activities. This can lead to the knee repeatedly giving way which damages other supporting structures of the knee joint, including the medial and lateral collateral ligaments and the joint cartilage pads (called the meniscal cartilages). In someone with a recent ACL injury, the risk of associated meniscal cartilage damage may be 30-40%. In someone who has had an ACL injury that has been present for several years, and who may have had several re-injuries to the knee, the risk of associated meniscus damage is 90%. Patients who want to participate in cutting and pivoting sports are advised to consider ACL reconstruction in order to minimize the risk of re-injury. The person who has instability even in daily activities, such as climbing stairs or stepping off a curb, may also need surgery to regain normal knee stability.There is no age limit to an ACL reconstruction. Rather, one should determine their symptoms and desired activity level when deciding on an ACL reconstruction. How is the ACL reconstructed? The ACL may now be reconstructed with arthroscopic techniques. A replacement graft is precisely positioned in the knee joint at the site of the former ACL and then fixed to the thigh and lower leg bones with screws. Options for the type of replacement graft include autograft (the patient's own tissue-patellar tendon (see picture) or hamstring tendons) or allograft (donor tissue from a cadaver). The type of graft most suitable for each patient is decided with the doctor. The procedure takes about 60-90 minutes and may be done on an outpatient basis (without spending the night in the hospital). How is the knee cared for after surgery? At the end of surgery, the knee joint is instilled with anesthetic to reduce postoperative discomfort.Your incisions will be closed with absorbable sutures (that is, they do not need to be removed) and a light dressing will be applied to the knee. A long white stocking will be applied to hold the dressing in place. Finally, your leg will be placed in a knee immobilizer following surgery. From the operating room you will be transferred to the recovery room for approximately one to two hours. Once it is felt you are awake enough to return home, we will discharge you unless there is a problem controlling your pain with oral medication, an inability to urinate, or significant nausea that prevents adequate oral intake. This occus in only a small number of patients. During the first 24 hours you should limit your walking as much as possible. The leg should be elevated on 2 to 3 pillows, above your heart. You may apply ice to your knee for 20 minutes every 2 hours as needed. Ice will help decrease swelling and is most effective the first 48 hours after surgery. We encourage you to wear the immobilizer except when doing your exercises you were shown by the therapist. You can bear weight on your operated leg as much as pain allows. Keep your incision clean and dry. It is common to experience some bloody drainage from the knee for the first 24-36 hours. If this occurs, simply reinforce the dressing with sterile gauze. Another common occurrence is a low-grade fever during the first 24-48 hours. The fever is usually below 101 degrees and slowly resolves. Tylenol may be used if this occurs. If the fever is greater than 101 and is associated with shaking and chills and increasing knee pain, please call us as this may be an early indicator of infection. How long is the recovery program? Your newly reconstructed ACL undergoes a biologic transformation form the time of implantation until amost one year postoperatively. Studies indicate that your graft may initially be stronger than a normal ACL, but quickly loses strength to reach its weakest point by one month. It then gradually regains strength over the next 6-8 months. Your rehabilitation after surgery is designed to re-establish motion and strength during this remodeling. Initially, activities are permitted which cause the least strain on the reconstructed ligament. The priority is to obtain motion first, followed by strengthening. During the first week, the priority is to allow the incisions to heal and to achieve full extension. That is why we suggest you sleep in the knee immobilizer and start knee extension exercises. The early protective phase is from the second week until the eigth week. His is a transition period where the emphasis shifts from range of motion and weight bearing to strengthening and maintaing of aerobic conditioning. This will be guided by your physical therapist. By 3 to 4 months, we will begin to phase you into your desired sport by allowing agility drill and sport-specific training on a light level. By 6 to 8 months, our goal is to have you ready to return to your desired sport. Do I need a brace? You do not necessarily have to wear a sports brace to return to your desired sport. No study has conclusively shown that the brace prevents injury to your graft or to a normal ACL. If you are returning to a high-risk sport, such as basketball, football, soccer, volleyball, or singles tennis, many patients have found that wearing a sports brace for the first year is comforting. |
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| Articular cartilage |
| Lateral meniscus |
| Femur |
| Medial meniscus |
| PCL ACL |
| Posterior cruciate ligament |
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| Normal ACL |
| Torn ACL |
| Anterior cruciate ligament |
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| Patella Tendon |
| Patella |
| Tibial tubercle |
| Femur |
| Tibia |
| Femur |
| Reconstructed ACL |
| Tibia |
| Blair A. Rhode, M.D. ________________________________ Sports Medicine Knee/Shoulder/Elbow Reconstruction Specialist *Board Certified* |
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