The Effect of Anterior Cruciate Ligament

Rupture of the anterior cruciate ligament (ACL) is a com-mon injury. Up to 77 % of patients evaluated with acute trau-matic hemarthrosis of the knee are estimated to have an injury of the ACL, often without clinically noticeable abnormal joint laxity.5,16,26,30 Acute rupture of the ACL is often associ-ated with meniscal tears, chondral damage, and injury to the medial collateral ligament (MCL).5,8,16,26,30 As the ACL injury becomes more chronic, an increasing incidence of joint swelling, instability, and meniscal tears is found, even-tually resulting in progressive osteoarthritis.2,13,27,28 In com-bined ACL and MCL injuries, the MCL does not heal as well as it does in isolated MCL injuries.6,17,25,32,41 A potential explanation for the poor outcome after ACL injury is that the changes in tibiofemoral joint kinematics associated with ACL injury disturb the normal function of other tissue structures of the knee.3,12,18,25,36,38 Numerous in vivo studies have demonstrated that the ACL plays an impor-tant role in restraining anterior translation and interna