Nonresorbable polymers in bone surgery.

Area of Science:

• Biomaterials Science
• Polymer Engineering
• Orthopedic Surgery

Background:

• Polymers for bone surgery implants require strength, stiffness, biocompatibility, and stability under sterilization.
• Ultra-high molecular weight polyethylene (UHMWPE) is used in joint replacements but faces challenges with wear particle generation, leading to prosthetic loosening.
• Acrylic bone cement offers immediate fixation but has drawbacks like toxic residual monomers and high curing temperatures causing thermal bone necrosis.

Purpose of the Study:

• To review the properties and applications of various polymers used in orthopedic implants.
• To highlight the limitations of current materials such as UHMWPE and acrylic bone cement.
• To introduce Polyetheretherketone (PEEK) as a promising alternative high-performance polymer for long-term implantation.

Main Methods:

• Literature review of polymer properties relevant to orthopedic applications.
• Comparative analysis of mechanical, chemical, and sterilization resistance of different polymers.
• Evaluation of clinical performance and limitations of existing implant materials.

Main Results:

• UHMWPE exhibits good wear and damping but wear particles remain a significant issue.
• Acrylic bone cement provides rapid fixation but poses risks of monomer toxicity and thermal necrosis.
• Polyacetal resins (POM) demonstrate high chemical and mechanical resistance for long-term implants.
• PEEK shows enhanced stability at sterilization temperatures and under irradiation, positioning it as a superior alternative to POM.

Conclusions:

• PEEK is a highly stable, biocompatible polymer suitable for medical-grade applications and long-term implantation.
• PEEK is poised to replace POM in future orthopedic implant designs due to its advanced properties.
• Further research and clinical validation are essential to fully leverage PEEK's potential in bone surgery.