The point of view of the veterinary surgeon: bone and fracture

It is important to understand the biomechanics of fractures if the morphological characteristics of fracture, fracture treatment and fracture healing are to be understood. Because of the mechanical properties of bone, which is stronger in compression than in tension, a fracture line is initiated perpendicular to the direction of tension or in shear. The mechanical properties of bone are also time-dependent (viscoelasticity). Subsequently, when the load is applied at a higher load range, a greater amount of energy is stored within the bone, resulting in a more severe fracture (high energy fractures). There are five types of fracture: tension, compression, torque, bending, and shear, with typical morphologies: transverse fractures in tension, fracture line at 45 degrees to the long axis of the bone in compression, spiral fracture in torsion, combined transverse and butterfly fracture in bending, shear line when the overload is applied eccentrically. These different morphological types are shown on radiographs.