Polyetheretherketone in Orthopedic Plate Design to Facilitate Fracture Recovery

Abstract

Polyetheretherketone (PEEK) is becoming an interesting alternative to titanium alloys and stainless steel in orthopedics. This study compares two types of PEEK fracture plates (natural and carbon reinforced) with titanium plates of the same design. Custom designed locking orthopedic plates made from titanium alloy, natural PEEK and carbon reinforced PEEK were tested mechanically in compression and by finite element (FEM) analysis. An anatomically correct, artificial human tibia bone was used as a model for polyurethane bone models in mechanical analysis and as a model for the 3D scan used in the FEM analysis. Plate dimensions were 100 mm x 20 mm x 5 mm and M5 locking screws were created from each material. Six cyclic mechanical compression tests from 0 to 1,000 N per construct were analyzed as well as 50, 100, 200, 400, 600, 800 and 1,000 N compression tests in the FEM analysis. In the mechanical analysis, carbon reinforced PEEK consistently experienced the most plate deformation. At 200 N, natural PEEK shows more deformation than the titanium alloy but switches at 1,000 N giving titanium the most deformation. The FEM analysis consistently shows natural PEEK experiences the most strain followed by reinforced PEEK and then the titanium alloy. It is shown that the custom fracture plates made from the two PEEK materials are likely too soft to be successful in long bone fractures. It is also shown that the same plates made with Ti-alloy may be too stiff to induce successful secondary fracture recovery.

Keywords

• polyetheretherketone
• peek
• orthopedic plate
• fem analysis
• fracture fixation
• mechanical analysis
• diaphyseal fracture