I-Corps: Translation Potential of Mechanically Compliant Fracture Fixation Plates for Long Bone Fractures

The broader impact of this I-Corps project is based on the development of a bone plate for treating fractures of long bones (such as the humerus, femur, and tibia) that is a single-piece and mechanically compliant (flexible). The plate improves clinical care outcomes by reducing fracture non-unions, which are extremely burdensome for patients physically, mentally, and financially. The technology improves equity for women, are they are disproportionately affected by non-unions in long bone fractures. The technology may reduce the long bone non-union rate (currently 5 - 20%), saving approximately $68,000/patient. This research informs future work across other applications in orthopedics. This I-Corps project utilizes experiential learning coupled with a first-hand investigation of the industry ecosystem to assess the translation potential of the technology. The solution is based on the development of fundamental knowledge that establishes the feasibility, limitations, and general principles of single-piece, flexible, fracture fixation plates for delivering controlled micromotion in long bone fracture healing. The technology leverages mechanical compliance to achieve this micromotion. The innovation includes: 1) the design of a single-piece, linear motion compliant mechanism bone plate, reducing the part count and assembly relative to alternative dynamic plates; 2) novel analytical models to select geometry of flexible elements, which allow the tuning of plate stiffness for various clinical scenarios without changing the material; 3) subtractive and additive manufacturing methods for machining thin flexible members which must endure many loading cycles; and 4) retaining critical plate features present in current rigid plates (i.e. locking screw holes, stainless steel materials, limited contact regions on the bone-facing side of the plate) to both preserve surgical technique and create a feasible regulatory clearance pathway with the Food and Drug Administration. This innovation introduces a resource for surgeons to reduce the stiffness of plated fractures, which has been shown to reduce non-unions, without the introduction of new materials, friction and wear, assembly of multiple components, or modified surgical technique. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.