Numerical Analysis of Stabilization of a Horse’s Third Metacarpal Bone Fracture for Prediction of the Possibility of Bone Union

Horses have been companions of people for thousands of years. Areas in which humans use these animals include, for example, transport, participation in sports competitions, or during rehabilitation (hippotherapy). Unfortunately, injuries such as lower limb fracture very often require euthanasia due to the significant difficulties in conducting fracture therapy/repair. Therefore, there are still many possibilities for the improvement of existing treatments. The aim of the study was to conduct a numerical analysis enabling the prediction of bone union of the third metacarpal bone of a horse. The loading conditions and type of fracture were based on a pony weighing 120 kg; however, research on a live animal was not the purpose of this study. Numerical studies were carried out for three different methods of stabilization using bone plates in the Ansys program (lateral, anterior, and lateral–anterior stabilization). An algorithm based on the Carter model was used to predict bone union, while linear-coupled models were used to describe the behaviour of materials. The authors also performed dynamic analyses in the Abaqus/Explicit program to determine the maximum speed at which the horse could move so that the fracture would not deepen. For dynamic analyses, the authors used nonlinear models—Johnson–Cook in the case of the 316L surgical steel material and cortical bone. Material failure was described using the Johnson–Cook failure model for steel and the limit strain model for cortical bone. A series of numerical simulations allowed to determine the direction of bone union building, and the most favourable case of stabilization was determined.