Low Energy Orthopedic Instruments and Fixation Strategies

Reducing the energy requirements for orthopedic instruments is desirable for many reasons. In situations with limited energy resources, such as relief efforts for natural disasters, reducing energy requirements for orthopedic instruments would increase the availability of powered surgical tools. Additionally, alternative power sources, without the environmental concern of batteries for disposal, could be used with low energy instruments, bringing more powered surgical tools into these types of situations. Even in situations where energy is available, it is desirable to reduce the energy used by surgical tools. For example, reducing energy requirements in surgical drilling could reduce the rates of drill bit wear and fracture and the risk of injury to the surgeon. Reducing energy requirements is also beneficial to decrease the amount of energy dissipated in the form of heat; limiting thermal necrosis and subsequently improving healing and the ability of the cut surface to property anchor to an implant or close a gap. Surgical implant, cutting tool, and power source designs can be investigated to reduce the energy requirements for orthopedic surgical procedures. Small diameter pins in external fixators require less energy for insertion and are therefore well suited for low energy designs. The feasibility of using small diameter pins in cases of external fixation is investigated using three-dimensional numerical models. The process of drilling is widely applied in orthopedic surgical procedures and is particularly useful in fracture fixation. An understanding of how geometric design parameters affect the performance of orthopedic drill bits is desired to guide future low energy designs. This work details the development and validation of plane strain and three-dimensional orthogonal cutting models and three-dimensional drilling models of bone, utilizing Arbitrary Lagrangian Eulerian adaptive meshing. An experimental study was conducted to investigate the performance of a particular orthopedic drill bit design against other current designs and to compare its performance with the results from the three-dimensional drilling numerical model.With a focus on the reduction of energy requirements in orthopedic surgical procedures, alternative power sources can be investigated. This work includes a feasibility study of a proposed alternative power source for use with pneumatic surgical drills.