PEEK for Orthopedic Surgery

In orthopedic surgery, innovation is critical to improving patient outcomes and quality of life. For nearly 30 years, orthopedic surgery innovations that have been making waves in the field include using high-performance polymers, particularly Polyetheretherketone (PEEK). In this technical post, PDC explores the unique properties of PEEK and examines its application-specific advantages and considerations for orthopedic surgery.

Understanding PEEK: A High-Performance Polymer PEEK, short for Polyetheretherketone, is a semi-crystalline thermoplastic polymer known for its exceptional mechanical properties, chemical resistance, and biocompatibility. These properties make PEEK ideal for various medical applications, including orthopedic implants.

Advantages of PEEK in Orthopedic Surgery:

  1. Biocompatibility: PEEK is biocompatible, well-tolerated by the human body, and minimizes the risk of adverse reactions or inflammatory responses.
  2. Mechanical Strength: PEEK exhibits high mechanical strength, comparable to that of bone, which allows for the design of load-bearing orthopedic implants capable of withstanding physiological stresses.
  3. Radiolucency: Unlike metal implants, PEEK implants are radiolucent, meaning they are transparent to X-rays. This enables clear visualization of the surrounding bone tissue during post-operative imaging, facilitating accurate assessment of bone healing and implant integration.
  4. Fatigue Resistance: PEEK demonstrates excellent fatigue resistance, ensuring long-term durability and reliability of orthopedic implants under cyclic loading conditions.
  5. Elastic Modulus Similar to Bone: The elastic modulus of PEEK is similar to that of cortical bone, reducing stress shielding and minimizing the risk of implant-related complications such as stress fractures and bone resorption.

Considerations for Orthopedic Applications: While PEEK offers numerous advantages for orthopedic surgery, several factors should be considered:

  • Sterilization Compatibility: PEEK implants must be compatible with common sterilization methods such as autoclaving and gamma irradiation to ensure sterility and patient safety.
  • Surface Modification: Surface treatments such as plasma etching or coatings may be employed to enhance the osseointegration of PEEK implants and promote bone ingrowth.
  • Implant Design: Careful consideration should be given to the design and geometry of PEEK implants to optimize load transfer, minimize stress concentrations, and ensure proper fixation within the bone.

Material Selection: While PEEK is well-suited for many orthopedic applications, alternative materials such as titanium or cobalt-chromium alloys may be more appropriate for some instances based on specific patient needs and surgical requirements.

Polyetheretherketone (PEEK) is a high-performance polymer with immense potential for revolutionizing orthopedic surgery. Its unique combination of biocompatibility, mechanical strength, and radiolucency makes it an attractive choice for orthopedic implants, offering numerous advantages for patients and surgeons. By leveraging the inherent properties of PEEK and addressing key considerations in implant design and material selection, we can continue to push the boundaries of innovation in orthopedic surgery and improve patient outcomes in the future.

Mastery in Precision Molding – Insights from Our Journey:

When designing and injection molding PEEK medical devices, consider these top three areas:

  1. PEEK tends to outgas because of its higher molding temperatures. Experienced mold designers select vent location and vent depth to successfully relieve gases that could cause voids due to incomplete fill.
  2. Conversely, PEEK also exhibits a low viscosity at melt temperature and tends to flash into small interstices in the injection mold. Appropriate location and dimension of venting determine the success or failure of a PEEK injection molding tool.
  3. When molding PEEK, thermal control imparts crystallinity to the polymer structure, reducing mold stress, which could result in post-molding part warping.

PDC holds over 25 years of experience designing injection mold tools for PEEK and producing medical device PEEK implants for our medical device customers. At PDC, you have a trusted partner to thoroughly plan and review the Design for Manufacturability of your novel PEEK medical device, navigating undercuts, tolerances, thin walls, draft, and core pin sizes. While PEEK presents design for manufacturing challenges, PDC’s expertise and experience help customers to reduce risk and ensure success for their new product programs.