ARUP; ISBN: 978-0-9562121-5-3 - CMBBE 2012 - Cardiff University

FINITE ELEMENT ANALYSIS OF POLYETHERETHERKETONE
AS A LONG BONE FRACTURE PLATE MATERIAL
1. ABSTRACT
Jason Sanderson 1 , Nobuki Murayama 2 , Nishimura Takuya 1 ,
Hiroshi Mizuta 3 , Takako Ishii 4 , Yoshitaka Nakanishi 5
Polyetheretherketone (PEEK) is a high strength, biocompatible thermoplastic currently
used for various medical and non-medical applications. In orthopedics it is currently
used for cranial plates, spinal and dental implants and diaphyseal nails. Some
advantages that PEEK materials hold over metallic implants include controlled
radiolucency, chemical inertness, and a variable elastic modulus which, if properly
modified, may limit stress shielding. However, when used in a potentially high load
region of the body, PEEK plates may not provide proper stability for successful fracture
healing. In a previous study, observed strain and interfragmentary motion within the
osteotomy were above acceptable levels for promotion of fracture healing (1) . The
current study proposes a redesigned PEEK orthopedic plate which includes a ladder-like
titanium inner reinforcement intended to increase the resistance to deformation of the
fracture plate. Finite element analysis is used to assess its capabilities as a long bone
diaphyseal orthopedic plate.
2. INTRODUCTION
The most common fracture plates can be either compression or locking in design and
are made from stainless steel or titanium alloys. These metallic implants are known to
cause stress shielding which has been shown to cause bone atrophy and increase
fracture recovery time (1, 2) . Recently, the thermoplastic polyetheretherketone (PEEK)
has been used as a new material in diaphyseal nail, cranial, spinal, and dental orthopedic
implants. It has multiple advantages over metallic materials such as radiolucency and
chemical inertness. Perhaps most important is its variable elastic modulus which, if
adjusted properly, can be used to reduce stress shielding during fracture healing. The
current study builds upon a previous study, which analyzed different types of PEEK
materials in orthopedic plates and compared them with a medical grade titanium alloy (1) .
The finite element method (FEM) is used to compare the effectiveness of reinforced
(titanium inner reinforcement) PEEK orthopedic plates with plates made of solid
titanium or solid PEEK in a high load, long bone, simple diaphyseal fracture.
1 Student, Graduate School of Science and Technology, Kumamoto University, Kurokami 2-39-1,
Kumamoto, 860-8555, Japan
2 Professor, Graduate School of Science and Technology, Department of Computer Science & Electrical
Engineering, Kumamoto University, Kurokami 2-39-1, Kumamoto, 860-8555, Japan
3 Professor, Graduate School of Science and Technology, Faculty of Life Science, Kumamoto University,
Kurokami 2-39-1, Kumamoto, 860-8555, Japan
4 Orthopedic Resident, Kumamoto Kinoh Hospital, Kumamoto, Yamamuro 6-8-1, 860-8518, Japan
5 Professor, Graduate School of Science and Technology, Faculty of Engineering, Kumamoto University,
Kurokami 2-39-1, Kumamoto, 860-8555, Japan