Stress-protection after external fixation on the intact rabbit tibia

Area of Science:

• Orthopedics
• Biomedical Engineering
• Bone Physiology

Background:

• Metal plates cause bone loss due to stress protection.
• External fixation is used in bone fracture treatment.

Purpose of the Study:

• To investigate if external fixation causes a stress-protecting effect on intact bone.
• To compare the effect of external fixation to that of metal plates.

Main Methods:

• External mini-fixation applied to rabbit tibiae.
• Biomechanical testing (three-point bending) and bone mineral content measurement (photon absorptiometry) at 6 and 12 weeks.

Main Results:

• No significant changes at 6 weeks.
• Significant reduction in bone strength (87%) and stiffness (88%) at 12 weeks.
• Significant reduction in bone mineral content (90%) in the stabilized segment at 12 weeks.

Conclusions:

• External mini-fixation induces a stress-protecting effect on rabbit tibiae.
• This effect occurs later and is less pronounced than with metal plates.