Cartilage attachment morphology of the fetal cruciate ligaments of the knee: An immunohistochemical study using human fetal specimens

Abstract

Fetal cruciate ligaments of the knee provide two types of cartilage attachments: to a cartilage fovea or a simple continuation to the perichondrium. To examine a difference in matrix substance between a ligament attachment to the fovea and another attachment to the perichondrium. We histologically observed 12 human fetal femurs in which the posterior (or anterior) cruciate ligament provided a fovea-type (or a perichondrium-type) attachment. Immunohistochemistry of matric substances (aggrecan, versican, tenascin-c) was performed. In the knees, aggrecan was consistently positive in any cartilage, versican was in the joint surface and tenascin-c in the perichondrium. In contrast to the femoral attachment, the anterior and posterior cruciate ligaments consistently continued to the perichondrium at the tibial attachment (versican-, tenascin+). In the femoral condyles, tenascin-immunoreactivity was seen in both of a fovea-type and a perichondrium-type attachments, but versican was not in both. During development of the cartilage fovea, the growing ligament seemed to push the perichondrium into the cartilage and, much or less, the tenascin-positive perichondrium was likely to be involved into the fovea.