Influence of Early Ovariohysterectomy on the Mechanical Properties of Rabbit Medial Collateral Ligament

Female athletes have significantly higher incidence of anterior cruciate ligament (ACL) injuries than males participating in similar sports [1]. To date, no clear explanation has emerged for this disparity. However, hormonal differences may provide an explanation because some ACL injuries have been linked to physiologic fluctuations in estrogen levels over the menstrual cycle [2]. Receptors for estrogen have been identified in rabbit and human ACLs and medial collateral ligaments (MCLs) [3]. Increased estrogen levels caused decreased fibroblast proliferation and collagen synthesis in cell cultures from human and rabbit ACLs [4]. Since fibroblasts maintain collagen production and degradation in ligaments and collagen is the major load-bearing component of ligaments, estrogen may affect knee ligament mechanical properties.