If you've ever read the sports pages, watched a sporting event or competed in a sport yourself, it wouldn't take you long to come across at least one ACL injury. The legs that were relied on completely are no longer stable. Major surgery followed by up to a year off of sports, all the time hoping that once through it all you will be able to return to sports. The athlete not only has to recover physically but mentally from an injury as serious as an A.C.L. injury. Every athlete wants to avoid knee injury while every coach hopes his players can.
The knee is a hinge joint in which the end of the femur links to the top of the tibia. The four major ligaments that stabilize the knee are the M.C.L., L.C.L., P.C.L. and the A.C.L. The medial collateral ligament (M.C.L.) and the lateral collateral ligament (L.C.L.) cover the inner and outer sections of the knee. They prevent the joint from bending inward and outward. The Posterior cruciate ligament runs from the anterior of the femur to the posterior of the tibia. The anterior cruciate ligament runs from the anterior of the tibia to the posterior of the femur. These two ligaments form and "X" within the knee, which stabilizes the tibia beneath the femur and limits the rotation of the tibia.(1) The size and strength of the ligaments will depend on the size and the make up of the individual. On average, the length of the ACL is between 28 and 34 mm, the width between 8 and 12mm, and between 4 and 6 mm thick (2). Within this structure there are numerous non-parallel fibers that together behave as three evident bundles (antermedial, posterolateral and intermediate). Variations in the lengths of their fibers and the ability of the A.C.L. to rotate slightly make flexion and tension of the leg possible (3). .
The cruciate ligaments can be referred to as the crucial ligaments of the knee, since they control several of the crucial motions (5). The A.C.L .is the only ligament that is able to prevent the femur sliding over the tibia.