Knee Arthroplasty

PEEK-OPTIMA polymers can be used as a bearing surface in a variety of different arthroplasty devices, including knee, hip and finger joints.

PEEK-OPTIMA Wear Performance can increase knee implant longevity.

In 2010 more than 90,000 knee revision surgeries were performed in the US and Europe. This indicates 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.

Hinge constructs made from PEEK-OPTIMA Reinforced and PEEK-OPTIMA Wear Performance offer superior cold-flow resistance as well as dimensional stability during the device lifetime (>15 years) compared to traditional hinge mechanisms that use UHMWPE, which resists dislocation. In addition, the PEEK-OPTIMA polymer has a flexural strength similar to the cortical bone, thus reducing stress shielding and improving patient comfort. Its proven biocompatibility and biostability in implantable devices worldwide provides safety, longevity and reassurance to patients and surgeons alike.

References:

• In an In-vitro knee wear simulation study, the wear resistance of PEEK-OPTIMA Reinforced was found to be very low compared to traditional polymers such as UHMWPE. The wear particulate response was equivalent to the inflammatory response of UHMWPE, but due to lower particle load less activity is expected. (Grupp et al, European Orthopaedic Research Society (EORS), 19th Annual Meeting Vienna, 2011; Utzschneider et al, Acta Biomaterialia, 2010)
• Further wear simulation revealed comparable low wear and no macroscopic surface fatigue in a new rotating-hinge knee design with highly congruent flanges and axles bushings made of CFR-PEEK articulating to zirconium nitride and cobalt-chromium. (Grupp et al, Acta Biomaterialia, 2013)
• Hinged-mechanism constructs made from PEEK-OPTIMA Reinforced or Wear Performance grades have been used in CE marked and FDA approved revision knee systems since beginning of 2010. Several thousand knee-revision implants containing these parts are already in clinical use.