FDA Clears TKA System With Novel UHMWPE Crosslinked Surface

The U.S. Food and Drug Administration (FDA) has granted 510(k) clearance to a knee joint patellofemorotibial polymer/metal/polymer semi-constrained cemented prosthesis.

According to the 510(k) summary document, the knee system is intended for “prosthetic replacement in treatment of the following:

• Patient conditions of non-inflammatory degenerative joint disease (NIDJD): avascular necrosis and osteoarthritis
• Patient conditions of inflammatory joint disease (IJD): rheumatoid arthritis
• Patients with failed previous surgery where pain, deformity, or dysfunction persists
• Correctable varus-valgus deformity and moderate flexion contracture
• Revision of a previously failed knee arthroplasty
• Patients who require a total knee replacement.”

The manufacturer of the system, Salt Lake City based Total Joint Orthopedics, Inc. (TJO), has introduced a number of truly novel joint reconstruction implants which are differentiated by their advanced materials technologies.

The brand name for this novel total knee implant is Klassic^® Knee System.

According to the company’s 510(k) summary document, the Klassic Knee System is indicated for “cemented use only, except for the Klassic Femur with Cobalt 3D™, and the Klassic Tibial Baseplate with Ti-Coat^®, which are indicated for cementless use.”

The Klassic Knee System includes Alchimist, LLC’s AlchemXE^® chemically crosslinked ultra-high molecular weight polyethylene (UHMWPE) technology. According to the company, AlchemXE “blends dicumyl peroxide and vitamin E with UHMWPE during consolidation, then uses proprietary technology to crosslink the material, resulting in high wear resistance and excellent long-term oxidative stability without the need for radiation crosslinking.”

Additionally, a “proprietary heat treatment improves the mechanical properties and reduces the by-products of the peroxide chemistry.”

Referring back to the 510(k) summary document, the purpose of the application was to “add Klassic Knee CR/Congruent Tibial Inserts and Ultra-PS^® Tibial Inserts, which are fabricated with E^X Poly, to the Klassic Knee System. E^X Poly is a crosslinked UHMWPE containing alpha-tocopherol. The subject Klassic Knee CR/Congruent and Ultra-PS Tibial Inserts are available in various sizes and thicknesses to match patient anatomy.”

In order to qualify for the shorter and earlier 510(k) clearance the device must be substantially equivalent to a predicate device. Here, the Klassic Knee CR/Congruent and Ultra-PS Tibial Inserts with E^X Poly are substantially equivalent to the “primary predicate Klassic Knee System Tibial Inserts with E-link Poly with respect to indications, material, design, and function.”

Alchimist is a medical device technology company. It develops materials to improve the performance of orthopedic implants.

Restoration Medical Polymers, based in Columbia City, Indiana, develops and tests implantable polymers for the orthopedic industry. Alchimist partnered with Restoration Medical Polymers to develop and produce its novel UHMWPE technology.