Introduction Anterior Cruciate Ligament Injury (ACLI) is most often a result of low-velocity, noncontact, deceleration injuries and contact injuries with a rotational component. Contact sports also may produce injury to the anterior cruciate ligament (ACL) secondary to twisting, valgus stress, or hyperextension all directly related to contact or collision. The importance of the ACL has been emphasized in athletes who require stability in running, cutting, and kicking. The ACL- deficient knee has also been linked to an increased rate of degenerative changes and meniscal injuries. For these reasons, approximately 60,000-75,000 ACL reconstructions are performed annually in theUnited States. Pathophysiology The ACL is composed of densely organized, fibrous collagenous connective tissue that attaches the femur to the tibia. The ACL is composed of 2 groups, the anteromedial and posterolateral bands. During flexion the anterior band is taught while the posterior is loose; during extension, the posterolateral band is tight, while the anterior band is loose. The ACL attaches to bone through a transitional zone of fibrocartilage and mineralized cartilage. On the femur, the ACL is attached to a fossa on the posteromedial edge of the lateral femoral condyle. The tibial insertion is located in a fossa that is anterior and lateral to the anterior tibial spine. The tibial attachment is noted to be somewhat wider and stronger than the femoral attachment. Read More Biomechanics The ACL is the primary (85%) restraint to limit anterior translation of the tibia. The greatest restraint is in full extension. The ACL also serves as a secondary restraint to tibial rotation and varus/valgus angulation at full extension. Since the relationship between the tibia and femur provides little bony stability, the ligamentous structures must provide stability. When the ACL is injured, a combination of anterior translation and rotation occurs. The average tensile strength for the ACL is 2160 N. This is slightly less than the strength of the posterior cruciate ligament and approximately half as strong as the medial collateral ligament (MCL). Read More Frequency An estimated 200,000 ACL-related injuries occur annually in theUnited States, with approximately 95,000 ACL ruptures. Approximately 100,000 ACL reconstructions are performed each year. The incidence of ACL injury is higher in people who participate in high-risk sports such as basketball, football, skiing, and soccer. When the frequency of participation is considered, a higher prevalence of injury is observed in females over males, at a rate 2.4-9.7 times greater for females Read More Medical-Legal Considerations |
Medical-legal issues from ACL injury and graft replacement generally arise from complications during surgery. Initial misdiagnosis of ACL injury also can be a source of potential litigation. Obtain a complete history from the patient. The mechanism of injury for ACL tear is fairly consistent. A thorough physical examination helps the physician confirm the diagnosis, and an MRI identifies additional possible injuries to other ligaments or cartilage. Potential for a lawsuit arising from improper physical therapy also exists. If the therapist is too aggressive in rehabilitation exercises and rupture of the ACL graft occurs, some patients might consider litigation. Read More | 
