Material Properties and Engineering Performance of Bone Fracture Plates Made from Plant Fiber Reinforced Composites: A Review

Bone fracture plates are usually made from titanium alloy or stainless steel, which are much stiffer than bone. However, overly stiff plates can restrict axial interfragmentary motion at the fracture leading to delayed callus formation and healing, as well as causing bone "stress shielding" under the plate leading to bone atrophy, bone resorption, and plate loosening. Consequently, there have been many prior efforts to develop nonmetallic bone fracture plates with customized material properties using synthetic fibers (e.g., aramid, carbon, glass) in polymer resin. Even so, plant fibers (e.g., flax, roselle, sisal) offer additional advantages over synthetic fibers, such as availability, biodegradability, less toxicity during processing, lower financial cost, and recyclability. As such, there is an emerging interest in using plant fibers alone, or combined with synthetic fibers, to reinforce polymers for various applications. Thus, this is the first review article on the material properties and engineering performance of innovative bone fracture plates made from composite materials reinforced by plant fibers alone or supplemented using synthetic fibers. This article presents material-level fiber properties (e.g., elastic modulus, ultimate strength), material-level plate properties (e.g., fatigue strength, impact toughness), and bone-plate engineering performance (e.g., overall stiffness, plate stress), as well as discussing general findings, study quality, and future work. This article may help engineers and surgeons to design, fabricate, analyze, and utilize novel bone fracture plates.