The biology of anterior cruciate ligament reconstructions.

Ligaments, including the anterior cruciate ligament (ACL), have a limited biological response to injury. The same healing process affects graft tissues used to reconstruct the ACL. These biological processes interact with mechanical forces to transform the grafts into tissues, which are expected to functionally replace the ACL. Although these grafts may undergo "ligamentization," they may not undergo "ACL-ization." Further study of the important relationship between these biological and biomechanical interactions is warranted.