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Related Experiment Video

Updated: Jan 26, 2026

A Reliable and Reproducible Critical-Sized Segmental Femoral Defect Model in Rats Stabilized with a Custom External Fixator

A Reliable and Reproducible Critical-Sized Segmental Femoral Defect Model in Rats Stabilized with a Custom External Fixator

Published on: March 24, 2019

A Reliable and Reproducible Critical-Sized Segmental Femoral Defect Model in Rats Stabilized with a Custom External

Benjamin Kerzner¹, Hannah L Martin², Michael Weiser¹

¹Department of Orthopedics and Rehabilitation, University of Wisconsin-Madison.

Journal of Visualized Experiments : Jove

|April 9, 2019

Summary

Researchers developed a reliable rat femur model for studying bone healing. Recombinant human bone morphogenetic protein-2 (rhBMP-2) significantly improved healing in critical-sized defects, unlike collagen sponges alone.

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Last Updated: Jan 26, 2026

A Reliable and Reproducible Critical-Sized Segmental Femoral Defect Model in Rats Stabilized with a Custom External Fixator

A Reliable and Reproducible Critical-Sized Segmental Femoral Defect Model in Rats Stabilized with a Custom External Fixator

Published on: March 24, 2019

Establishment of a Segmental Femoral Critical-size Defect Model in Mice Stabilized by Plate Osteosynthesis

Establishment of a Segmental Femoral Critical-size Defect Model in Mice Stabilized by Plate Osteosynthesis

Published on: October 12, 2016

A Simple Critical-sized Femoral Defect Model in Mice

A Simple Critical-sized Femoral Defect Model in Mice

Published on: March 15, 2015

Area of Science:

Orthopedic Research
Regenerative Medicine
Biomaterials Science

Background:

Animal models are crucial for orthopedic research, particularly for studying bone healing and evaluating new treatments.
Critical-sized segmental defects present significant clinical challenges, necessitating robust small animal models for research.

Purpose of the Study:

To establish an optimized, reproducible surgical protocol for creating a 5 mm critical diaphyseal defect in a rat femur.
To evaluate the efficacy of recombinant human bone morphogenetic protein-2 (rhBMP-2) in promoting bone healing within this model.

Main Methods:

A custom jig and external fixator were used to create and stabilize a 5 mm femoral defect in rats.
Defects were treated with either a collagen sponge alone or a collagen sponge soaked in rhBMP-2.
Bone healing was assessed over 12 weeks using radiography and histological analysis.

Main Results:

Femoral defects treated with collagen sponge alone failed to heal (non-union).
rhBMP-2 treatment resulted in significant periosteal callous formation and new bone remodeling.
The external fixation effectively stabilized the defects throughout the 12-week study period.

Conclusions:

The developed surgical model provides a reliable and reproducible method for studying bone healing in vivo.
rhBMP-2 demonstrates significant potential for promoting bone regeneration in critical-sized defects.
This streamlined model is suitable for investigating orthopedic biomaterials and regenerative therapies.