#ACL stands for anterior cruciate ligament which is one of the four major ligaments of the knee. It connects the femur (thigh bone) to the tibia (shin bone), and allows you to pivot, twist, and turn. while preventing the two bones from separating and from sliding too far forward.
ACL injuries are very common in an athletic population such as soccer, basketball, and football. Many of these injuries occur when an athlete makes a sudden turn or “cut”, but the foot stays planted on the court or ground. Landing from a jump with a twisting motion, like in volleyball or basketball, also can injure the ACL, as well as a hyperextension of the knee and deceleration. In contact sports like football, a direct blow to the outside part of the knee can also cause an ACL injury.
Signs that you may have damaged or torn your ACL include: noise like a “pop", pain at the knee, immediate swelling, and a feeling of instability or giving way in the knee. The diagnosis of an ACL tear can typically be made by an experienced #sportsmedicine specialist based on the players history of the injury and physical examination. Imaging studies are usually obtained when an ACL tear is suspected. Plain x-rays are usually normal; magnetic resonance imaging (MRI) can be a valuable aid in making the diagnosis and identifying associated injuries.
Treatment is based on each individual person, their activity level, symptoms, and desire to return to sports. Athletes who attempt nonoperative management and continue to play sports frequently have persistent knee instability or a shifting sensation, and they may also complain of swelling or locking which makes return to high-level sports that involve cutting and pivoting very difficult. Persistent instability has been shown to result in cartilage damage in over 90% of patients if left untreated.
People who choose not to have surgery to repair or reconstruct a torn ACL usually do not participate in sports or activities that involve running, twisting, cutting or jumping, or in aggressive activities that place stress on the knee. Nonsurgical management in these types of individuals often does not result in further symptoms. Therefore, activities such as golf, cycling, swimming, and walking can usually be performed even with a torn ACL tear in these less active patients. By undertaking a rehabilitation program, it is possible to function normally without having surgery to reconstruct a torn ACL. Physical therapy will be important to strengthen the knee joint, improve range of motion and normalize your function.
Most often, surgery is required to replace a torn ACL to reestablish normal knee stability and mechanics. In a few particular instances, a direct repair of a torn ACL by suturing the fibers back to the bone may be successful but continued research is needed to see the longterm outcomes. Most of the time surgeons use another piece of tissue, called a graft, to replace the torn ligament.
The tissue that is harvested for the graft can be either an autograft (your own tissue) or an allograft (tissue from another donor). Autografts most commonly come from the tendon that connects your kneecap to the bottom leg bone (the patellar tendon), from your hamstring tendons or from the tendon that connects the thigh to the kneecap (the quadriceps tendon). The choice of graft is dependent upon several factors that the surgeon will discuss with the patient preoperatively.
Overall outcomes, regardless of graft choice, have been favorable. Surgery is performed on an outpatient basis, and the surgery typically takes about 1-2 hours depending on any other injuries. Surgery will be performed using minimally-invasive small incisions with a camera and small instruments. Tunnels are formed in the bones, and the ends of the graft are placed in the tunnels and affixed to the bones to stabilize them while healing occurs. The articular cartilage and meniscus in your knee will be evaluated at the time of surgery as well, and any other needed surgery such as meniscus repair, will be performed at the same time.
If you think you may have an ACL tear, make an appointment to discuss your options.
If you are scheduled for an upcoming surgery, review our frequently asked questions "Preparing for ACL Surgery" guide.