An appropriately cross-linked polyethylene material, e-plus, a knee specific formula, is blended with vitamin E and formulated to reduce long-term wear1.
Re-Melting not Required
Because vitamin E stabilizes free radicals2, a melt-anneal step is rendered unnecessary.
A re-melt step, used for most highly cross-linked polyethylenes, reduces the mechanical properties and fatigue strength of irradiated UHMWPE2.
Blended
e-plus is the only FDA cleared blended vitamin E TKA component. UHMWPE resin is blended with pure liquid α-tocopheral (vitamin E), a naturally occurring anti-oxidant.
No Oxidation
During intense age testing1, e-plus exhibited no detectable oxidation.
Maximum Mechanical Strength1
The impact of oxygen exposure to e-plus samples was evaluated in accelerated aging tests. Un-aged and aged e-plus samples yielded the same results during yield strength testing, while a melt-annealed standard highly cross-linked material exhibited a 12% reduction in yield strength.
IZOD Impact testing, which can indicate the relative brittleness of a material, showed no change in performance between pre and post-aged e-plus.
Reduced Wear1
e-plus, when tested on an Instron/Stanmore knee simulator, had a 57% reduction in wear rate than already premium performing direct compression molded UHMWPE.
- e-plus is currently available for the 3DKnee TKA
- e-plus FDA cleared claims
References
1. E-plus testing data on file. Bench test results not necessarily indicative of clinical performance.
2. S.M. Kurtz. "The UHMWPE Handbook: Ultrahigh Molecular Weight Polyethylene in Total Joint Replacement". Oral E, Muratoglu OK. Chapter 15, "Highly Crosslinked UHMWPE Doped with Vitamin E". Elsevier Academic Press, 2009.