Biomechanical rationale and evaluation of an implant system for rib fracture fixation

BACKGROUND: Biomechanical research directed at developing customized implant solutions for rib fracture fixation is essential to reduce the complexity and to increase the reliability of rib osteosynthesis. Without a simple and reliable implant solution, surgical stabilization of rib fractures will remain underutilized despite proven benefits for select indications. This article summarizes the research, development, and testing of a specialized and comprehensive implant solution for rib fracture fixation. METHODS: An implant system for rib fracture fixation was developed in three phases: first, research on rib biomechanics was conducted to better define the form and function of ribs. Second, research results were implemented to derive an implant system comprising anatomical plates and intramedullary rib splints. Third, the functionality of anatomic plates and rib splints was evaluated in a series of biomechanical tests. RESULTS: Geometric analysis of the rib surface yielded a set of anatomical rib plates that traced the rib surface over a distance of 13–15 cm without the need for plate contouring. Structurally, the flexible design of anatomic plates did not increase the native stiffness of ribs while restoring 77% of the native rib strength. Intramedullary rib splints with a rectangular cross-section provided 48% stronger fracture fixation than traditional intramedullary fixation with Kirschner wires. CONCLUSION: The anatomic plate set can simplify rib fracture fixation by minimizing the need for plate contouring. Intramedullary fixation with rib splints provides a less-invasive fixation alternative for posterior rib fracture, where access for plating is limited. The combination of anatomic plates and intramedullary splints provides a comprehensive system to manage the wide range of fractures encountered in flail chest injuries.