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Updated: Mar 25, 2026
Transverse Fracture of the Mouse Femur with Stabilizing Pin
Published on: December 29, 2021
Effect of Stabilization on the Healing Process of Femur Fractures in Aged Mice
T Histing1, K Heerschop1, M Klein1
1a Department of Trauma, Hand and Reconstructive Surgery , Saarland University , D-66421 Homburg/Saar, Germany.
Background:
The influence of mechanical stability on fracture healing has previously been studied in adult mice, but is poorly understood in aged animals. Therefore, we herein studied the effect of stabilization on the healing process of femur fractures in aged mice.
Methods:
Twenty-four 18-month-old CD-1 mice were stabilized after midshaft fracture of the femur with an intramedullary screw. In another 24 18-month-old mice, the femur fractures were left unstabilized. Bone healing was studied by radiological, biomechanical, histomorphometric, and protein expression analyses.
Results:
After 2 and 5 weeks of healing, the callus of nonstabilized fractures compared to stabilized fractures was significantly larger, containing a significantly smaller amount of osseous tissue and a higher amount of cartilaginous tissue. This was associated with a significantly lower biomechanical stiffness during the early phase of healing. However, during the late phase of fracture healing both nonstabilized and stabilized fractures showed a biomechanical stiffness of ∼40%. Of interest, Western blot analyses of callus tissue demonstrated that the expression of proteins related to angiogenesis, bone formation and remodeling, i.e. VEGF, CYR61, BMP-2, BMP-4, Col-2, Col-10, RANKL, OPG, did not differ between nonstabilized and stabilized fractures.
Conclusion:
Nonstabilized fractures in aged mice show delayed healing and remodeling. This is not caused by an altered protein expression in the callus but rather by the excessive interfragmentary movements.
