Risk Factors and Predictors of Subsequent ACL Injury in Either Knee After ACL Reconstruction
Tears of the anterior cruciate ligament (ACL) are common in the active population. The ACL-deficient knee has significant risk of functional instability, future meniscal tears, and subsequent osteoarthritis.56 Reconstruction of a torn ACL is often performed with the goal of restoring stability to the knee and decreasing risk of subsequent injury to the knee. It is estimated that 200,000 ACL reconstructions (ACLRs) are performed annually in the United States (US) alone.9 Excellent results of ACLR, in terms of restoring functional knee stability, have been widely reported in the literature.7,56,61 During the 6- to 12-month recovery from an ACLR, there is a significant investment of time, discomfort, money, and effort by the patient. For the ACL graft to tear after a successful surgery and rehabilitation is a devastating event for the patient as well as the family, coach, and surgeon. Further, it has been demonstrated that revision ACLRs have inferior results compared with primary ACLRs.12,40,64 Unfortunately, it also is not uncommon to recover from an ACLR of one knee and then tear the native ACL of the contralateral knee.