Patients in the third class were able to perform mildly stressful sports (eg, jogging, swimming, biking, cross-country skiing). The second class included patients who were able to perform all ADL. The first class included patients who were able to perform only symptomatic activities of daily living (ADL). The total number of patients in these combined studies was 363. Mortality/Morbidity: Not a single report of mortality was found in 6 different studies examining the morbidity and mortality of ACL repair. Internationally: International statistics are not available. If all ACL injuries were repaired, the associated expenditure for 100,000 procedures would eclipse $2,000,000,000 annually. The average cost for surgical repair of an ACL tear is approximately $11,500. This estimate is low for women because ACL injury rates are estimated to be 2-8 times higher in women than in men participating in the same sports. This figure corresponds to an overall injury rate approaching 200,000 injuries annually. In the US: Epidemiologic studies estimate that approximately 1 in 3000 individuals sustains an ACL injury each year in the United States. This type of tear occurs primarily as the ligament is transected by the pivoting lateral femoral condyle. The more common ACL tear, however, is a midsubstance tear. Avulsion of ligaments generally occurs between the unmineralized and mineralized fibrocartilage layers.
The vascularity within a ligament is uniform, and each ligament contains mechanoreceptors and free nerve endings that are hypothesized to aid in stabilizing the joint. Ligaments receive their blood supply from their insertion sites. The ultrastructure of a ligament is close to that of tendons, but the fibers in a ligament are more variable and have a higher elastin content. The ACL, like all other ligaments, is composed of type I collagen. The patient states, “I planted, twisted, and then heard a pop.” Before the advent of arthroscopic knee surgery in the early 1970s, ACL tear was often a career-ending injury. This injury usually occurs during a sudden cut or deceleration, as it typically is a noncontact injury. An ACL tear is a common injury that occurs in all types of sports. The ACL provides 85% of the total restraining force to anterior translation of the tibia. The ACL is composed of 2 bundles, the anteromedial bundle and the posterolateral bundle. The ACL tracts from the tibia superiorly, laterally, and posteriorly to its insertion on the posterior aspect of the medial wall of the lateral femoral condyle. The anterior cruciate ligament (ACL) originates from the tibial plateau just medial and anterior to the tibial eminence.