Adjustable stiffness, external fixator for the rat femur osteotomy and segmental bone defect models

Area of Science:

• Orthopedics
• Biomedical Engineering
• Regenerative Medicine

Background:

• Mechanical environment significantly influences bone fracture healing.
• Clinical interest is growing in optimizing bone healing via mechanical stability.
• Preclinical research faces limitations in controlling the mechanical environment of healing bone defects.

Purpose of the Study:

• To design and utilize an external fixator for studying bone healing in large segmental defects and osteotomies.
• To enable controlled and adjustable axial stiffness during the in vivo healing process.
• To provide a reliable tool for preclinical research in bone regeneration.

Main Methods:

• Development of a novel external fixation device for rat models.
• Application of the fixator to create and stabilize a 5 mm femoral defect in rats.
• Monitoring of the healing process for at least 8 weeks, assessing stability, distortion, and infection.

Main Results:

• The external fixator successfully maintained a 5 mm femoral defect gap in rats throughout the 8-week healing period.
• No significant distortion or infection (including pin site infections) was observed.
• Reproducible and standardized stabilization of bone defects and osteotomies was achieved.

Conclusions:

• The developed external fixator provides a robust platform for in vivo preclinical research on bone healing.
• It allows for precise control and manipulation of the mechanical environment in rat models.
• This device is well-suited for investigating bone regeneration and repair mechanisms.