The stress-protecting effect of metal plates on the intact rabbit tibia.

The purpose of the present study was to find the extent of stress-protection by a steel plate (45 X 5 X 1 mm) on the rabbit tibia. The animals were sacrificed after 6, 12 and 18 weeks. The median strength after plate application was 84, 73 and 72%, respectively. The elastic stiffness of plated bones was also reduced, while the deformation at fracture showed no significant reduction. The mineral content in the bone segment previously covered by a plate was measured by photon absorptiometry; it was reduced after 12 and 18 weeks. The stress-protecting effect caused by this thin steel plate was less pronounced than that previously reported by groups using more rigid plates on rabbit tibiae. The stress-protecting effect increased up to 12 weeks, but subsequently no further increase occurred.