Fractures of the first phalanx were simulated in a compression testing device, investigation biomechanical conditions leading to these fractures.
Legs from either euthanised or slaugtered horses, which had been frozen by -21° right after the death of the horses, were prepared immediately after the thaw process.
A material testing machine of Walter & Bai AG (technical number PA 1050R, S/Nr. 405), was programmed to a load of a maximum of 50 kN. The distance was set on either 2 or 4 cm. The punch´s speed was set by 3 m/s.
In order to use the material testing machine the chuck had to be redesigned and stabilized. Within the first 10 examination series various fixation materials were used. But no fracture could be achived.
Either loosing of the sample or luxation of the fetlock joint occurred on loading, but no typical fractures could be achieved.
Using a fast drying cement within the 11th examination serie, with pressure applied directly to the sagittal notch and bilateral equal support of the distal joint surface, finally 15 fractures could be extended. All of the 15 fractures were midsagital though the load used varied between 3,83 kN and 43,23 kN.
The final results indicate that a bilateral support of the first phalanx under load leads to a microfracture first and the final fracture at second place.
Horse / first phalanx / fetlock / material testing machine / biomechanics / fracture