Anatomy of the anterior cruciate ligament

An internet-based literature review using the catalog of the National Library of Medicine for the keyword “anterior cruciate ligament” results in 5884 hits, thus reflecting the high importance of basic and clinical research. To achieve a satisfying surgical outcome after anterior cruciate ligament (ACL) reconstruction, a basic knowledge of the anatomy of the ACL is essential. The early manifestation of the ACL in the fetal knee joint suggests that the knee joint is early under the stabilization of the ACL. The origin of the ACL is at the medial surface of the lateral femoral condyle and runs distal-anterior-medial to the insertion at the medial tibial eminence. In the literature, a 2-bundle description of the ACL into anteromedial and posterolateral bundle has been accepted as a basis for the understanding the function of the ACL. Length and diameter of the native ACL may play an important role for choosing the type of graft and for the preparation of the graft. Microscopically, femoral origin and tibial insertion have the structure of a chondral apophyseal enthesis and can be separated into 4 layers. The collagen fibrils of the ACL are surrounded by connective tissue forming multiple fascicles. Proximal and distal vessels support a synovial plexus from which small vessels run into the ligament and align longitudinally parallel to the collagen bundles.