The volleyball match has been going on for over an hour. Both teams have been trading points and side-outs. The ball is set high outside so that the big outside hitter can put the ball away. He comes in hard, plants, leaps and smashes the ball down the line in twisting motion. As he lands on his right foot, a "POP" is heard and down he goes. What has just happened is occurring more and more often in athletics, the athlete has just torn the anterior cruciate ligament (ACL). In this paper I will describe ACL, how it is injured and diagnosed, how it is repaired and what is being done to prevent ACL injuries. The Anterior Cruciate Ligament (ACL) is one of two cruciate ligaments of the knee, the other being the Posterior Cruciate Ligament (PCL). These ligaments are the stabilizers of the knee. The ACL is a strip of fibery tissue, which is located deep inside the knee joint. It runs from the posterior side of the femur (thigh bone) to the anterior side of the fibia (shin bone) deep inside of the knee. The ligament is a broad, thick cord the size of a person's index finger. It has long collagen strands woven together in a fashion that permits forces of up to 500 pounds to be exerted. The function of the ACL is to prevent the tibia from moving in front of the knee and femur. The ACL also prevents hyperextension (or extreme stretching of the knee backward) and helps to prevent rotation of the tibia.The amount of knee ligament injuries have been on the rise in the recent years. Over the last 15 years, ankle sprains have decreased by 86% and tibia fractures by 88%, but knee ligament injuries have increased by 172 %. The injury usually occurs in either slow twisting fall, a sudden hyperextension, or sudden hyperflexion as an landing from jumping. When the injury occurs the athlete usually hears a "pop" and they will have immediate swelling of the knee. When the person tries to put weight on the leg it will feel like the knee isn't underneath the...
