The anterior cruciate ligament (ACL) runs from the front of the tibia (lower leg bone) to the back of the femur (thigh bone). It prevents the tibia from sliding forward and keeps the knee from pivoting (instability). The ACL sits in the center of the joint and has poor blood supply that contributes to its poor healing potential.
The ACL is often injured in sports with twisting type injuries or hyperextension injuries of the knee. ACL injuries can occur with rapid stopping while running and often as contact injuries. ACLs can be an isolated injury, but often occur with associated injuries to the meniscus (cartilage pads) or other ligament combinations. Females are known to have a higher rate of ACL injuries than males in the same sports.