Science Fair Project Encyclopedia
Anterior cruciate ligament
The anterior cruciate ligament (or ACL) is one of the four major ligaments of the knee. It connects from a posterio-lateral (back & outside) part of the femur to an anterio-medial (front & inside) part of the tibia.
Damage to the ACL frequently occurs with lateral blows to the knee (as happens with a tackle from the side in American football) and often is accompanied by injuries to the medial collateral ligament (MCL) and the medial meniscus , which is attached to the MCL; physicians are taught "...knee injuries come in threes - anterior cruciate, medial collateral, medial meniscus." A damaged ACL can be confirmed (clinically) by a physician with the anterior drawer test , the Lachman test, or an MRI.
Non-contact tears or ruptures of the ACL often occur when athletes moving quickly in one direction make a sharp or sudden change in direction (cutting). In jump sports, ACL failure has been linked to heavy or stiff landing as well as twisting or turning the knee while landing. Studies indicate that women in jumping and cutting sports such as basketball, volleyball, or football (soccer), are significantly more prone to ACL injuries than men; this is generally believed to be due to differences between the sexes in the angle between the hip and knee, general muscular strength, and possibly training techniques (a new study suggests hormone-induced changes in muscle tension associated with menstrual cycles may be an important factor [1]).
ACL injuries are also common in alpine skiing, partially because of improvements in boots. Today's boots have been successful in preventing many of the ankle and leg fractures once caused by accidents; however, the tradeoff has been that the stresses have been transferred to the knees, resulting in many ACL tears.
An ACL injury can often be debilitating for far longer than a broken leg.
Treatment
Replacement is also available via a posthumous donor, but there is a slightly higher risk of infection than with autologous tissue. The risk is still very small, and is estimated to be 1 in 3 million. Compared to the risk of chronic patellar tendinitis that could result from using your own tissue, it is relatively small.
See also
External links
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