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Back To: PATIENT ED
ACL InjuriesAnterior Cruciate Ligament, ACL  Over the past several decades, the incidence of skiing injuries has dropped in half from 7.5 per 1,000 skier days to 3 per 1,000 skier days. One of the main reasons for this is improved equipment. Although the incidence of ankle and leg injuries has declined, the relative incidence of knee injuries has not. Though skiing is a safe sport, falling is not. During a ski fall much of the energy is transmitted from the ski up the leg and absorbed by the knee. The length of the skis cause them to act as levers resulting in significant torque and subsequent strain on the bones and ligaments around the knee. The new multi-release bindings have saved the leg from severe fractures but the knee remains vulnerable. Hopefully with new technology, a faster releasing binding may ultimately help protect the knee from injury. The knee is one of the more frequently injured areas of the body from skiing. The ACL is the second most commonly injured ligament as a result of skiing. FUNCTION The ACL's main function is to prevent the tibia bone from sliding forward on the femur bone. Without a functioning ACL, the knee is unstable and this can lead to difficulty with certain athletic movements and put the knee at risk for injuring other structures such as the meniscus and articular cartilage. Without a functioning ACL, the natural history of the knee is one that will be unstable during athletic activities and a knee which will progress to early arthritis. PREVENTION Though the modern binding and the modern ski boot have protected the leg from various fractures and ankle injuries, they have not protected the knee from ACL tears. The best way to prevent an ACL tear is proper pre-season conditioning aimed not only on strength and endurance, but also on balance and agility. By working on these various aspects of condition, one may help prevent the circumstances which are responsible for ACL injuries. It has also been encouraged that when falling in a mechanism such as the phantom foot syndrome, to fall to the side rather than backwards. By fighting to regain balance, the forces across the knee are increased and the chances of ACL injury heightened. To prevent knee injuries, it is best to fall forward or to the side, if possible. It is also very important to use up to date equipment which is tuned and adjusted by experienced professionals. CAUSE  The most common mechanism of injury is called the "phantom foot syndrome." This occurs when the skier is falling backwards with the hips below the knees. The back side of the downhill ski hits the ground, causing an anterior directed force up through the lower leg which produces excessive strain on the ACL, thus causing an ACL tear. A twisting mechanics produced by the long lever arm (ski) can also produce sufficient torque to rupture the ACL. The second most common cause is a boot-induced ACL injury. This occurs during hard landings by off balance skiers. When the skier lands, the tail of the ski hits first driving the tibia out from under the femur, thereby tearing the ACL. An ACL injury is typically an all or none phenomenon. Sprains rarely occur and if the ACL is injured, it is usually completely torn. EXAM AND STUDIES  An ACL tear can most often be diagnosed by obtaining a clear history of the event and by a thorough knee exam. If any question remains, an MRI can be helpful to make a diagnosis NON -SURGICAL TREATMENT This is an option reserved for non-active individuals and elderly patients. Age is less of an issue as the population is getting older and more active. Non-surgical treatment would include muscle training (in particular the hamstrings) and bracing. However, no good study exists to support bracing as a treatment alternative. SURGICAL TREATMENT In most active individuals, surgical reconstruction of the ACL is recommended. It has been shown that repairing the ligament is ineffective and thus reconstructing the ligament using the patient's own patellar tendon or hamstring tendons is recommended. There are varying opinions as to which tissue makes the best ACL graft. Many surgeons favor the patellar tendon, where as others opt to use the hamstring. Both tendons are adequate and acceptable substitutes for the ACL. SURGICAL RECOVERY AND REHABILITATION Following surgery, an aggressive structured rehabilitation program is encouraged. Patients are allowed to bear full weight on the knee immediately after surgery and usually are on a stationary bike or "Stair Master" at two to three weeks. A brace is typically used for two weeks and patients are off of crutches after a week or so. Sport-specific activities are not begun until three months, and patients are usually not encouraged to go back to twisting or deceleration type of activities for 5-6 months following their surgery. Aspen Office 100 East Main Street, Suite 101 Ph.970/925-4141 Fax.970/925-4233 Glenwood Springs Office 622 19th Street Ph.970/945-8683 Fax.970/945-5843 Basalt Office (Midvalley Medical Center) 1450 East Valley, Suite 201 Ph.970/927-1757 Fax.970/927-8633
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