Anterior cruciate ligament

Anterior cruciate ligament
Diagram of the right knee. Anterior cruciate ligament labeled at center left.
Details
From	lateral condyle of the femur
To	intercondyloid eminence of the tibia
Identifiers
Latin	ligamentum cruciatum anterius
TA	A03.6.08.007
FMA	44614
Anatomical terminology []

The anterior cruciate ligament (ACL) is one of a pair of cruciate ligaments (the other being the posterior cruciate ligament) in the human knee. They are also called cruciform ligaments as they are arranged in a crossed formation. In the quadruped stifle joint (analogous to the knee), based on its anatomical position, it is also referred to as the cranial cruciate ligament. The anterior cruciate ligament is one of the four main ligaments of the knee, and the ACL provides 85% of the restraining force to anterior tibial displacement at 30 degrees and 90 degrees of knee flexion.

The ACL originates from deep within the notch of the distal femur. Its proximal fibers fan out along the medial wall of the lateral femoral condyle. There are two bundles of the ACL—the anteromedial and the posterolateral, named according to where the bundles insert into the tibial plateau. (The tibia plateau is a critical weight-bearing region on the upper extremity of the tibia). The ACL attaches in front of the intercondyloid eminence of the tibia, being blended with the anterior horn of the lateral meniscus.

These attachments allow the ACL to resist anterior translation and medial rotation of the tibia, in relation to the femur.

ACL tears are among the most common knee injuries, with over 100,000 tears in the US occurring annually. Most ACL tears are a result of landing or planting in cutting or pivoting sports, with or without contact. Most serious athletes will require an ACL reconstruction if they have a complete tear and want to return to sports, because the ACL is crucial for stabilizing the knee when turning or planting. Reconstruction is most commonly done by autograft, meaning the tissue used for the repair is from the patient’s body. Other times, a cadaver is used for tissue. The two most common sources for tissue are the patellar tendon and the hamstrings tendon. The surgery is arthroscopic, meaning that a tiny camera is inserted through a small surgical cut. The camera sends video to a large monitor so that the surgeon can see any damage to the ligaments. In the event of an autograft, the surgeon will make a larger cut to get the needed tissue. In the event of an allograft, in which material is donated, this is not necessary. The surgeon will make holes in the patient’s bones to run the tissue through, and the tissue serves as the patient’s new ACL. Recovery time ranges between one and two years or longer. A week or so after the occurrence of the injury, the athlete is usually deceived by the fact that he/she is walking normally and not feeling much pain. This is dangerous as some athletes start resuming some of their activities such as jogging which, with a wrong move or twist, could damage the bones. It is important for the injured athlete to understand the significance of each step of an ACL injury to avoid complications and ensure a proper recovery.