CFRP replaces UHMWPE in knee implants

Feb 01, 2012

Hinges in a newly developed knee replacement technology are made from carbon-fiber reinforced (CFR) polyetheretherketone (PEEK).

Aesculap, a division of healthcare supplier B. Braun Melsungen, is using PEEK-OPTIMA CFR in its FDA 510k-cleared and CE-Marked EnduRo knee revision system.

Design engineers hope the use of carbon fiber, the same reinforcement that's used in the fuselage of the

"Working with Invibio provided us with both a material and processing solution package that enabled our accelerated time to market requirement," said Ulf Grimm, Aesculap product manager for knee endoprostheses.

Fast market penetration

According to Aesculap, the EnduRo knee has received strong European market reception, gaining a 14% market share in Germany during the first year of availability and with more than 2000 prostheses implanted to date. The first implantation of the EnduRo knee in the United States took place late last year.

In 2010, Millennium Research Group estimated that there were more than 90,000 knee revision surgeries performed in the US and Europe, indicating that some 8% of all knee implant procedures result from failure of the initial knee implant. A contributing factor to these failures is dislocation, whereby the rotational axis slips out of its guide, requiring total replacement of the implant.

Better wear

CFR PEEK is intended to prevent dislocation compared to traditional hinge mechanism types that use ultra-high-molecular-weight polyethylene (UHMWPE). Invibio, the supplier of PEEK-OPTIMA, says that CFR provides greater wear and cold flow resistance as well as dimensional stability during the lifetime of the device (greater than 15 years), which aids resistance to dislocation.

Grimm says these are the benefits of using the new composite:

In 2011, Invibio Biomaterial Solutions was formed as a wholly owned subsidiary of Victrex plc to focus exclusively on the medical device market.

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