Estrogen-dependent tensile properties of the rabbit knee medial collateralligament

The influence of oophorectomy or continuous administration of estradiol on the tensile properties of the rabbit knee medial collateral ligament was in vestigated. Young postpubertal female New Zealand white rabbits were either oophorectomized or underwent a sham operation. The sham-operated animals r eceived in addition a daily dosage of 4 mg 17 beta-estradiol. After 5 month s the animals were killed, and the material properties of the bone-ligament -bone complex in one knee were determined using a material testing machine and video system, and compared to non-treated control animals. There was no difference in elastic modulus between the groups. However, the ligaments f rom low-dose estrogen-treated animals had a smaller cross-sectional area an d a higher ultimate tensile strength than those from controls or oophorecto mized rabbits (P<0.01-0.0003).