How is implantable PEEK used in veterinary medicine?
PEEK has been used successfully for implantable devices in human patients for more than 20 years. It also has applicability for treating animals that are a part of our home lives and often livelihoods. In humans, PEEK implants are widely used in spinal fusion, trauma fixation, cardiovascular, arthroscopic and dental medicine, among other fields. Before PEEK was approved for human implantation, it was validated in countless animal trials. In veterinary medicine PEEK implants are used in a narrower but important range of applications, including:
- Fractures – Untreated fractures can lead to permanent physical impairments in cats and dogs, as well as muscle or ligament damage. Treating the fracture, though, requires stabilization, and high strength PEEK implants can provide this.
- Hip dysplasia – Hip dysplasia is one of the most commonly inherited chronic medical conditions among dogs, and it can be seen in cats as well. In animals with hip dysplasia, the hip’s ball and socket joint does not develop properly, leading to contact between the ball and the socket. With time, this grinding motion can result in debilitating pain, inflammation, and loss of joint function. Hip dysplasia can range in severity, and in animal patients with severe pain or lameness, joint replacement surgery may be indicated. It is increasingly common for replacement joint components to be made from PEEK, because of its exceptional wear resistance and load-bearing properties.
Both hip dysplasia and fractures can result in long term complications if not treated properly, and treatment options are improving with time. Implantable PEEK medical devices comprise one such option for pet owners, and they are often used in the following applications:
- Screw, rod and plate systems – Trauma fixation typically requires the use of bone screws and plates or intramedullary nails to stabilize fractures. By doing so, the bone will heal faster and in a way that preserves motion and minimizes any long-term pain. PEEK rods can be used in conjunction with PEEK screw and plate systems to enhance their performance and minimize complications caused by micromotion.
- Artificial hip replacement – PEEK is an effective choice as a polymer for joint replacements in human patients with successful use in both knee and hip replacement surgeries. The same medical science is also being applied in veterinary medicine, where hip joint replacement can restore function in animal patients with hip dysplasia or other osteoarthritic conditions.
What are the advantages of implantable PEEK in veterinary applications?
Implantable PEEK is typically used as an alternative to metal implants, which have limitations that PEEK overcomes. As such, PEEK is considered a biomaterial of the future, with the potential to replace titanium and other metals in a number of applications. In trauma fixation and total hip replacement (THR) applications, implantable PEEK has the following advantages:
1. An elastic modulus similar to cortical bone
Aside from its excellent biocompatibility, PEEK’s elastic properties first drew researchers’ attention. That’s because it flexes and bears weight like cortical bone, so it doesn’t rob nearby bone tissue of needed stimulatory forces. By distributing weight instead of bearing it in a concentrated area, the healing bone won’t be subject to resorption, which can affect the bone’s long-term integrity. This is a particular problem associated with metal implants, which are much more likely to bear too much of the load and cause subsidence (or caving in) of neighboring bone. This is an important consideration in both trauma fixation and joint replacement applications.
2. A permanent solution due to low wear
Physicians and veterinarians would prefer to avoid revision surgeries if at all possible, as surgery always comes with risk. This risk is higher in older pets, who are more likely to be candidates for revision surgeries following joint replacement. It’s difficult to avoid these surgeries, though, because they are often the result of wear to the artificial joints. With time and wear, debris can produce inflammation to nearby tissue, or even result in tissue death. It’s a serious concern for older animals and one that’s magnified in active patients like younger dogs and those with high energy levels. A permanent solution is necessary to avoid revision surgeries, and device manufacturers have developed replacement joints made of PEEK that can meet the requirements.
3. Can be easily manufactured for any pet anatomy
Dogs and, to a lesser extent, cats are morphologically diverse, but fitting an implant to the animal’s anatomy is critical for maximizing recovery. This is a challenge with metal implants, but PEEK implants can be precisely sized to the patient’s anatomy, resulting in a perfect fit every time. Replacement joints are even available for toy breeds, using the same technology developed for larger breeds.
It’s important that veterinary teams be able to see how the implant is settling and whether it needs to be adjusted following placement. To do this, the implant often will be imaged during follow-up appointments. A major benefit of PEEK is that it can be modified into formulations that are radiopaque using standard imaging techniques like MRIs, CT scans and X-rays, making follow-up examinations easier and more accurate.
5. Can be modified to enhance osseointegration
Current generation PEEK implants have been designed to promote faster, more effective osseointegration. For instance, a THR joint may be coated with hydroxyapatite around the socket, which helps stimulate bone growth and provide a mineral-rich surface to which new bone may attach.
6. Performance Versatility
PEEK polymer lends itself to formulation modifications that tailor its performance to the requirements of different medical devices. Carbon reinforcement can be blended uniformly into the PEEK polymer to increase its load bearing properties for fixturing, for example, and additives can be introduced for radiopacity for accurate imaging.
7. Finished Product Manufacturing Options
Genesis Medical Plastics has the technology and capacity to supply customers with a variety of product forms that best fit their needs. We extrude biocompatible PEEK grades into rods and plates that are then machined into precision parts to support prototype through production quantities. Our injection molding operation also can convert PEEK into virtually limitless configurations where high quantities of the same precision parts such as suture anchors, screws and fasteners are required.
Implantable PEEK has been proven as a safe, effective biomaterial in some of the most complex surgical procedures in medicine. This now includes veterinary medicine, where the polymer’s well-established benefits over metals in human applications are providing a better quality of life for pets.