Women who play contact sports injure their ACLs about seven times more often than men who play such sports. So far, sports medicine experts have not been able to determine why women athletes have a higher risk of ACL injuries. Some researchers believe it's related to a slight difference in the anatomy of the knee in males and females. Others blame it on the effects of female hormones on body ligaments. Still others point to differences between females and males in skill, training, conditioning or even athletic shoes.

Symptoms

Symptoms of an ACL injury can include:

• Feeling a "pop" inside your knee when the ACL tears

• Significant knee swelling and deformity within a few hours after injury

• Severe knee pain that prevents you from continuing to participate in your sport (most common in partial tears of the ACL)

• No knee pain, especially if the ACL has been completely torn and there is no tension across the injured ligament

• A black and blue discoloration around the knee, due to bleeding from inside the knee joint

• A feeling that your injured knee will buckle, "give out" or "give way" if you try to stand