Torsional tests of long bones with computerized equipment

Area of Science:

• Biomechanics
• Orthopedic Research
• Materials Science

Background:

• Understanding the mechanical properties of bone is crucial for diagnosing and treating skeletal diseases.
• Existing methods for testing bone mechanics may lack precision or the ability to simulate complex loading scenarios.

Purpose of the Study:

• To describe a novel experimental method for studying the mechanics of entire diaphyseal bones using a computerized torsion machine.
• To evaluate the precision and capabilities of this new method for characterizing bone mechanical behavior.

Main Methods:

• Development and utilization of a computerized torsion machine capable of controlled continuous torsion to fracture.
• Implementation of non-linearity detection for reversal of torsion direction and controlled repeated loading/unloading cycles.
• Measurement of torque-twist curves to determine parameters like stiffness and residual deformation.

Main Results:

• The computerized torsion machine demonstrated good linearity and high precision, with a method error of 2.3% for stiffness determination.
• The system successfully controlled complex loading protocols, including repeated loadings and unloadings until final fracture.
• Analysis of entire dog femora revealed minor residual deformation before ultimate fracture, highlighting the method's sensitivity.

Conclusions:

• The described computerized torsion machine provides a precise and versatile method for investigating the mechanical properties of entire bones.
• This technique allows for detailed characterization of bone behavior under various loading conditions, advancing biomechanical research.
• The findings contribute to a better understanding of bone fracture mechanics and material properties.