Blood and lymph supply of the anterior cruciate ligament: Cadaver study by immunohistochemical and histochemical methods

Abstract

Injection techniques, immunohistochemical (antibodies against laminin), and histochemical (5-nucleotidase activity) methods were used to demonstrate the vascular pattern of the human anterior cruciate ligament (ACL). The major blood supply of the ACL arises from the middle geniculate artery. The distal part of the ACL is vascularized by branches of the inferior geniculate artery. The ligament is covered by a synovial fold where the terminal branches of the middle and the inferior geniculate artery form a periligamentous network. From the synovial sheath, the blood vessels penetrate the ligament in a horizontal direction and anastomose with a longitudinally orientated intraligamentous network. Within the ligament, the blood vessels are located in the loose connective tissue that is located between longitudinal fiber bundles. Compared to the surrounding synovial layer, the number of vessels in the ligament substance is greatly reduced. Three avascular areas can be detected within the ligament. In the attachment zones of the ligament to the femur and the tibia, the immunohistochemical reaction with antibodies against laminin is negative. A third avascular zone is located in the anterior portion approximately 0.5 cm proximal to the tibial insertion. The absence of blood vessels in this area may be the result of compressive stress caused by the anterior end of the notch. Lymphatics accompany most of the smaller blood vessels, showing similar regional distribution.