Importance of UHMWPE-Vitamin E

Report By: Kyle Johnson

Applicable Industries: Medical & Orthopedics

Best Use-Cases: Medical Implants

Introduction:

Ultra-high molecular weight polyethylene (UHMWPE) is a commonly used material across multiple industries. UHMWPE is known for its exceptionally high impact strength, high energy absorption, low coefficient of friction, limited wear, and biocompatibility. Having superior density, much force and energy is required to create the material from premium resins, specialty compression molding and extrusion processes. EPTAM buys stock shapes of UHMWPE from a major strategic material supplier and performs 5-axis precision machining to create high-performance, tight-tolerance medical parts that can be implanted within the human body. UHMWPE can be cross-linked with antioxidants to boost material properties. Vitamin E has a positive influence for biocompatibility, commonly used as a cross-linking stabilizer to maintain mechanical properties and avoid material degradation. Parts produced from UHMWPE blended with vitamin E are targeted for use within shoulder, knee, and elbow replacements. “Clinical results and studies demonstrate significant improvements achieved in wear reduction and further improvements are in constant development.”

Purpose:

Seeking opportunities in UHMWPE-Vitamin E machining provides the ability to make a lasting impact in the biomedical industry. More importantly, it helps to make people’s lives more fulfilling by providing high-performance implantable parts. EPTAM has the manufacturing capabilities and experience machining this material, and therefore will continue to explore opportunities within the biomedical industry to support customer design initiatives and project goals.

Background:

EPTAM has specialized in multi-axis subtractive machining of plastic components for decades, continuing to grow more predominant within the medical device industry as a key supplier to many top tier OEMs. UHMW is a material that has also been available for decades. Dating back to its first polymerization in the 1950’s, it was most commonly seen in packaging solutions, conveyer and food processing equipment, bearings, guard rails, etc. UHMW does not absorb water and is not affected by chemicals. This material has been used in the medical device industry, specifically Total Joint Replacements (TJR), since research was performed by Sir John Charnley, who “conducted experiments to study the low coefficient of friction of the natural joint.”1 The first bearing material used in the development of low friction joint restoration or arthroplasty was?PTFE (Teflon), which resulted in extensive wear and biocompatibility issues, prompting experts to develop the bearing surfaces from UHMWPE. In the early 1960’s, Charnley implanted the first UHMWPE hip prosthesis which became the material standard for all articulating surfaces of TJR until highly cross-linked variants (such as antioxidants like vitamin E to improve mechanical properties) were developed. These efforts, specific to TJR, have revolutionized the health and comfort of surgical patients, improving their well-being, providing them with increased mobility and reducing discomfort.

EPTAM specializes in manufacturing medical grade plastics such as UHMWPE. Unlike moisture absorbent material such as Nylons and Teflon which creep, UHMWPE is rigid and dimensionally sound, enabling the manufacturing team to hold to tight tolerances and achieve a high rate of repeatability. This is proven by using automated inspection techniques like CMM (Coordinate Measuring Machine) or programmable vision systems. EPTAM uses software to track data for correlation purposes which ensures that all inspection gauges and techniques agree on measurement. Capability studies are performed to analyze part-to-part dimensional behavior to better understand the distribution trend. Passing a capability study signifies that the manufacturing process is controlled and repeatable.

Results:

EPTAM is proud to have produced over 15,000 ankle implants of various sizing for a medical customer since 2020. EPTAM continues to produce UHMWPE implants, expanding the portfolio by accepting new medical device contracts and focusing on TJR for years to come. EPTAM excels in machining UHMWPE due to its advanced experience with dozens of polymers, all reacting uniquely to tooling and clamping stresses. With the vast experience of producing and inspecting quality machined product, EPTAM is the ideal contract manufacturer.

Conclusion:

EPTAM is committed to providing outstanding products and services, satisfying regulatory requirements, maintaining an effective quality management system, and promoting a culture of excellence for employees with the goal of improving and enhancing the community.

EPTAM understands the importance of modern medical practices and surgical procedures, appreciating the design aspect while educating personnel about customer product final applications. Consequently, EPTAM will continue to support its medical OEM customers in machining high quality products. UHMWPE is a crucial material for TJR and other medical devices which affect lives for the better.

Footnotes:

1 Musib, M. K. (n.d.). A Review of the History and Role of UHMWPE as a Component in Total Joint Replacements. International Journal of Biological Engineering. Retrieved from Scientific and Academic Publishing article.