Stress-protecting effects of semi-rigid titanium alloy plates on osteotomized rabbit tibiae

We have examined the stress-protecting effects of titanium alloy (Ti-6A1-4V) plates of various thicknesses on osteotomized rabbit tibiae. We used three kinds of plates: One had a load-deflection rate close to that of intact rabbit tibiae (Group A), the other two had rates of one-fourth (Group B) and one-eighth (Group C) that of intact rabbit tibiae. No mechanical failure in the plates was observed, and bone healing occurred by eight weeks after operation in every group. Bone mass at 24 weeks after operation showed significantly less reduction in Groups B and C than in Group A. In biomechanical tests at 24 weeks, maximum energy stored to the maximum load in Group C had recovered significantly more than that of Group A. These findings suggested that it is possible to make a semi-rigid metal plate without using composite materials.