The Journal of Bone and Joint Surgery, Vol 60, Issue 2 230-234, Copyright © 1978 by Journal of Bone and Joint Surgery, Inc
Influence of age and sex on the strength of bone-ligament junctions in knee joints of rats
CM Tipton, RD Matthes and RK Martin
The bone-ligament junction strength of femur-medial collateral
ligament-tibia complexes in rats was measured in situ at various ages
during a two-year period. Male rats had a higher junction strength than
female rats, a difference that became apparent when the animals were sixty
days old and in male but not female animals subsequently paralleled the
changes in body weight. However, on a bodyweight basis, the junctions were
stronger in female than in male rats and this sex difference was evident at
fifteen days old and persisted thereafter. Regression analysis between body
weight and junction strength indicated that female rats had a significantly
higher slope than males, which suggested that the sex differences were due
to a hormonal factor or factors. Other measurements showed that elastic
stiffness, failure energy, and collagen concentration in the ligament
increased, whereas the water content of the ligament decreased with age.
Most of these changes could be attriubted to the aging process and not the
sex of the animal. It was concluded, however, that the strength of the
insertion sites of ligaments on bones are responsive to the hormonal
fluctuations that occur with aging.