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Protocol for Developing a Femur Osteotomy Model in Wistar Albino Rats
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Histomorphometric Analysis of Callus Formation Stimulated by Axial Dynamisation in a Standardised Ovine Osteotomy
K M Reich1,2, S Tangl1,2, P Heimel2,3
1Karl Donath Laboratory for Hard Tissue and Biomaterial Research, Department of Oral Surgery, University Clinic of Dentistry, Medical University of Vienna, Vienna, Austria.
Biomed Research International
|March 21, 2019
Summary
Cyclic axial dynamisation of fractures may improve bone healing quality. Increased displacement amplitudes showed a trend towards larger callus areas and more compact bone, suggesting enhanced fracture repair.
Area of Science:
- Orthopedics
- Biomaterials Science
- Regenerative Medicine
Background:
- Cyclic axial dynamisation is used to promote bone healing after fracture stabilization.
- Previous research has primarily focused on biomechanical properties and the quantity of new bone, with less attention to callus tissue quality.
Purpose of the Study:
- To investigate the impact of cyclic axial dynamisation on both the quantity and quality of callus in a sheep delayed fracture healing model.
- To evaluate the effect of varying displacement amplitudes on histological and compositional aspects of callus formation.
Main Methods:
- 41 sheep underwent transverse osteotomies stabilized with external fixators.
- 32 sheep received axial stimulation with different displacement amplitudes (0.8, 0.4, 0.2, 0.0 mm) for six weeks.
- A control group (9 sheep) had rigid fixation; histological sections were analyzed using histomorphometry.
Main Results:
- Increasing displacement amplitudes showed a trend towards larger total callus area, new bone area (nB.Ar), and cartilage area (Cg.Ar).
- New bone and cartilage areas were significantly larger on the anterior compared to the posterior callus side across all groups.
- Treatment groups exhibited predominantly compact bone, while the control group showed more porous bone, indicating improved callus quality with dynamisation.
Conclusions:
- Cyclic axial dynamisation, particularly at higher displacement amplitudes, appears to enhance the quality of newly formed bone callus, leading to more compact bone formation.
- The study introduces a method to assess local callus compactness, which, combined with biomechanical testing, can reveal relationships between tissue distribution and bone strength.
- This quantitative assessment of callus quality offers valuable insights beyond traditional histomorphometry for understanding fracture healing.
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