US Patent Number
A method is provided for reducing the amount of wear particulates generated by a total joint orthopaedic implant. The implant consists of two matched articulating components wherein at least one of the components is made of polymer or other material with similar physical properties. The method includes the steps of placing the total joint orthopaedic implant in a fluid bath and articulating the implant in the fluid bath for at least 1,000 cycles. The articulation may be performed in three stages. In the first, the implant is articulated under a load of substantially 0.1-500 Newtons with sliding speeds of substantially 0.01-0.5 meters per second. During a second stage the articulation takes place under a load of substantially 100-2,500 Newtons with sliding speeds of substantially 0.01-0.5 meters per second. In the third stage the articulation takes place under a load of substantially 2,500-10,000 Newtons at sliding speeds of 0.5-2.0 meters per second. The method also includes pre-implantation creeping for the polymer component. This improves the wear resistance of the polymer component, as well as, increases the conformity between the matched articulating components resulting in reduced wear particulate generation.
University of Kentucky Research Foundation, Lexington, Ky.
Pienkowski, David A. and Lee, Kwon-Yong, "Method for Reducing the Generation of Wear Particulates from an Implant" (1998). Biomedical Engineering Faculty Patents. Paper 1.