Biomechanical evaluation of fixation methods used in the treatment of fifth metatarsal fractures and the development of a novel biodegradable screw design.

Abstract

The fifth metatarsal is essential for balance control during gait and remains susceptible to proximal fractures such as the Jones fracture due to its limited vascularity, making the choice of fixation method of critical importance. The study was conducted to biomechanically compare conventional fixation techniques and identify the most effective strategy for Jones fracture management, culminating in the design and rigorous evaluation of a novel biodegradable implant. A volumetric model of the fifth metatarsal with fixation constructs was developed using medical imaging and digital design tools, and its mechanical performance was assessed by finite element analysis. The proximal end of the metatarsal bone was immobilized, and a 60 N-according to literature-was applied to the distal end; frictional interaction was incorporated at the fracture interface to simulate realistic mechanical conditions. The mechanical properties of Ti6Al4V and CrNiMo alloys were used for the implant models. The intramedullary screw model registered the lowest stress values for both materials, prompting subsequent material and design modifications. A magnesium-based biodegradable material was adopted, and mechanical analyses were conducted again following the implementation of requisite design refinements. The modified biodegradable implant was verified to provide adequate structural performance, indicating its suitability for Jones fracture fixation.