Pseudoelastic NiTiNOL in Orthopaedic Applications

Pseudoelastic NiTiNOL presents an attractive material option for devices used in clinical orthopaedic applications. The capacity of the material to exert sustained compression during shape recovery aligns well with the mechanobiological factors associated with bone healing, particularly in applications such as fracture healing and joint fusion. Orthopaedic medical devices which have incorporated NiTiNOL are increasing in number, with two noted examples including staples and intramedullary nails. Early NiTiNOL devices utilized shape memory NiTiNOL, but the logistical difficulties with maintaining a cold state in the clinic or limited force-generation for materials warmed from room temperature to body temperature have led to pseudoelastic NiTiNOL devices dominating clinical usage. Both pre-clinical biomechanical and clinical studies have shown that these devices do exert sustained compression beyond the abilities of competing static devices, and largely have resulted in superior clinical outcomes, such as higher fusion rates and faster times to fusion. Given these results, continued adoption of existing NiTiNOL devices and future development of new orthopaedic devices utilizing the material should continue.