The anterior cruciate ligament, also known as the ACL, is a critical part of the knee anatomy. This ligament is responsible for keeping the tibia and the femur aligned in the knee joint. Damage to this ligament may involve a tear, leading to instability in the joint. Patients with an ACL tear may need surgery to resume normal activities.
Injury Causes
ACL repair can be necessary as a result of different injuries, SportsMed.org explains. One cause can be trauma from a direct blow to the knee, which can happen as a result of a football tackle. The ACL can also become damaged when a person tries to suddenly change direction, or if the knee becomes hyperextended. These kinds of ACL tears are especially common among athletes who participate in sports that require agility, including soccer, basketball, football and skiing.
Signs and Diagnosis
The ACL requires surgical repair if the ligament is torn. Patients who develop a torn ACL will often hear or feel a "pop" in their knee at the time of the injury, according to the Mayo Clinic. An ACL tear can be diagnosed using a thorough physical exam of the injured area, as well as imaging studies, such as magnetic resonance imaging (MRI). The MRI is especially important for detecting these kinds of injuries, the American Academy of Orthopedic Surgeons explains, because ACL tears often occur in conjunction with damage to the meniscus, knee cartilage and other ligaments, which may also require surgical repair.
Grafts
In general, a torn ACL must be replaced with a graft taken from a tendon, the American Academy of Orthopedic Surgeons explains, because repair of the original ligament is rarely successful. Allografts, which are tendons taken from cadavers, can be used, but there is a greater risk of infection and graft failure when these tissue sources are used. Frequently the tendon graft is taken from another area of the patient's body; common harvest sites include the patellar, hamstring and quadriceps tendons. The exact type of graft used depends on the preferences of the physician and the patient.
Surgery
ACL repair is almost always done under general anesthesia, Arthroscopy.com explains. Once the graft has been prepared, holes will be drilled into the femur and the tibia where the ACL used to be connected. The graft can then be threaded through these drill holes so that it is in the same position as the old ligament. Once the reconstructed ligament has been anchored in place using surgical staples or some other attachment, the incisions are sewn up and the patient is put in the recovery room. After the surgery, the patient will require physical therapy to strengthen the joint and re-establish a full range of motion.
Risks
Even if the ACL surgery is successful, some patients may still experience pain, weakness or stiffness in the knee joint, Medline explains. Patients also run the risk of developing an infection at the surgical site, particularly if a graft from a cadaver is used. There is also the risk that an artery in the leg will be damaged during the surgery, which can lead to blood loss. Patients may also have an allergic reaction to the anesthesia or develop breathing problems. Patients should discuss these risks with their physician before undergoing ACL repair.
