Biomechanics of bone and fractures

During the past decade, an explosion of new information and techniques avai lable to the veterinary orthopedic surgeon with regard to methods used for fracture fixation has occurred. Because of the numerous options available f or successful fracture management, it has become increasingly necessary for an orthopedic surgeon to have a basic understanding of biomechanics pertai ning to bone and implant systems. Mechanics describe the dynamic forces act ing on a stucture which act to change the structure's form and direction of motion. Biomechanics is simply the application of mechanical engineering p rinciples to biologic systems in the hope of gaining insight into (1) the m aterial and structural characteristics of a living material such as bone, ( 2) the impact of intrinsic as well as extrinsic physiological and nonphysio logical forces on a biological system, and (3) the influence of modem techn ology on a biological system. Understanding the mechanical and structural characteristics of normal bone allows comprehension of how different extraneous forces can act on bone, cr eating predictable fracture patterns, and why some fractures have specific anatomical predispositions. A working knowledge of the forces causing fract ures as well as of the mechanical principles used to stabilize a fracture d uring bone healing allows educated decision making when choosing an implant for fracture stabilization. In addition, this information enables the vete rinary orthopedic surgeon to scientifically critique new implant systems as they are developed with regard to their inherent ability to effectively co unteract the potential postoperative disruptive forces acting on a fracture .