Torsional force applied to the tibia of living lambs in an attempt to change the bone rotational axis
Volpon, Jose Batista; Falcai, Mauricio Jose; Moro, Carlos Alberto; Leal, Daniel Mendes.
Acta cir. bras.;
29(3): 193-200, 03/2014. tab, graf
Artigo
em Inglês
| VETINDEX
| ID: vti-10211
Resumo
To evaluate the effects of torsional force on the rotational axis of living lamb tibias. METHODS: An external fixator device was designed to apply rotation to the tibias of lambs. Once a week, the bone distal extremity was rotated 2º. After achieving ~20º of internal rotation, the turning was discontinued and the device was maintained in situ for one month and euthanasia occurred in group A (n=10) after this. In group B (n=9) euthanasia occurred three months after removing the device. Computed tomography scans evaluated the rotational angle; dual-energy X-ray absorptiometry assessed the bone mineral density, and conventional and polarized light microscopy studied the bone microstructure. RESULTS: In group A, the mean angle of the external rotation in the control tibias was 24º and 8º in the twisted tibias (p<0.0001); in group B, the angle was 23º (control) and 7º (twisted, p<0.0001), with no differences between groups A and B (p=0.9567). The BMD increased in the twisted tibias in group A (p<0.0001) and in group B (p=0.0023), with no between-group differences (p>0.05). Microscopically, the twisted tibias showed asymmetrical subperiosteal bone deposition on the lateral cortex surface. CONCLUSION: Gradual torsion applied to the immature tibia significantly modified its rotational axis.(AU)
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