A new material for hip prosthesis without debris release

Today, in spite of the long experience acquired in the field of total hip replacements, prosthetic systems are still far from reproducing the natural system. One of the main causes of long term failure is the amount of wear debris produced by the tribological coupling between acetabolar cup and femoral head. Therefore, in order to increase the “ longevità “ of total hip replacement joint, the rate of wear debris generated by the articulation surface must be reduced. This paper present an alternative bearing surface that is made of Peek a polymer composite. This composite utilizes a high strength polyether ether ketone (Peek) as the matrix and a high strength carbon fiber as reinforcement. This material have shown excellent tribological performance in industrial bearing applications and also both the peek and the carbon fiber materials have been shown to be highly biocompatible. The authors carried out experimental research in order to investigate the formation of debris caused by tribological coupling of three type of Peek versus cobalt chrome alloy .The three type of Peek are: Ketron Peek® 450G, Larpeek ® Peek CA , carbon fiber reinforced Peek composite, with 30% of randomly oriented carbon fiber (extrusion or injection); Peek C.F, carbon fiber reinforced Peek (made in laboratory) with 30% of monodirectional carbon fiber, under pressure in a mould at melting point. The wear tests (ASTM 99G) has been performed with a pin-on disc tribometer in an air environment, under the following conditions: dry, water lubrication using demineralized water as a lubricant and human serum. A careful methodology of filtering under vacuum was used to extract the debris from the lubricants used in the tribological test. SEM and EDS analysis was used to characterize the debris. This study sets new bases for the design of modern hip prosthesis without debris release .