Fracture Fixation Device Testing

The Challenge

Fracture fixation plates are used to immobilize bones that have been fractured or severely broken. These plates are most commonly made from titanium or stainless steel. Both have similar mechanical properties, including stiffness and ultimate tensile strength, as native bone. These plates are often irregular geometries and come in a variety of sizes to accommodate different size bone fractures in the body. For example, a plate used to immobilize a fractured bone in a femur will be very different than one used in an ankle, finger, or jaw. The irregular geometry and size range of fracture fixation plates makes them challenging components to test. In addition, in most cases, these plates remain within a patient for life and must be able to withstand the dynamic motion of the body over decades of time.

In order to understand the mechanical properties of fracture fixation plates, a range of both static and dynamic tests are required. Monotonic flexural, tension, and compression testing is necessary to understand modulus and ultimate tensile strength. Given the irregular geometry of fracture fixation plates, measuring strain is a challenge. 2D and 3D modeling techniques, such as finite element analysis, are often conducted to understand full-field stress and strain properties of fracture fixation plates. For monotonic tensile, compression, or flexural testing, our Digital Image Correlation software paired with our Advanced Video Extensometer allows researchers and scientists to visualize and quantify the full-field strain properties of these plates. For all fatigue tests, we recommend using our ElectroPuls™ systems. Specifically, we recommend either the E3000 or E10000 Linear-Torsion test system. The ability to test plates simultaneously in axial loading and torsional loading best represents realistic loading conditions in the human body.