Wear Particle Analysis & Testing Services |
|
ISO 17853:2003: Wear of implant materials - Polymer and metal wear particles Isolation, characterization and quantification. How it’s doneThe implant, such as an artificial hip, artificial knee, spinal disc, nucleus replacement, posterior dynamic fixators or facet joint replacement, is loaded in a biomechanical testing simulator, designed to apply loads and motion in accordance with the relevant standards that are designed to simulate the normal use of the joint. The implants are tested to 10 million implant components is measured as a function of wear cycles and the serum or saline is sampled for wear particle (debris) analysis.
6° of Freedom has developed state-of-the-art, custom software to process this data. Once the image data has been processed, the results are tabulated into the required histograms. The information is processed so that histograms showing wear particle (debris) size distributions, and wear particle (debris) shape distributions.
Energy dispersive x-ray analysis is routinely used to determine the composition of the particles found on the filter. Although wear volumes can be reduced through the use of improved engineering materials, wear particles themselves remain a concern. The size, shape and number of particles that are produced are vital to know so as to establish what kind of biological responses will occur due to the implants installation. References
|
|
|
It is an accepted fact that a major cause of osteolysis and implant failure is the build-up of wear debris during articulation of artificial joints. Articulation of the orthopaedic implant (such as an artificial hip, artificial knee, spinal disc, nucleus replacement, posterior dynamic fixators, facet joint replacement) means that the two wear surfaces slide against each other. The development of wear particles (debris) over time is inevitable. Wear particle (debris) analysis must be conducted in order to determine the quantity and size range of wear particles (debris) produced following standard biomechanical testing. The FDA and CE require particulate analysis on wear debris generated during biomechanical testing.
Wear particles (debris) are captured by the membranes and imaged using a scanning electron microscope at the relevant magnifications. This is sufficient for polymer particles, but analysis of ceramic and metallic particles requires finer filter filtration due to the extremely fine wear debris. A high resolution, scanning electron microscope is used for the imaging of wear particles (debris) from the sub-micron sized filters. A number of images are taken from each filter and then processed using image analysis software.
The results collected in this systematic way enable the characterisation of the particles generated by the simulation test. A distribution of particle size per ml of the test reservoir can be determined and from this a histogram can be produced. Additional results for the wear particles (debris) can be generated, such as particle mass distribution per ml, particle count distribution per ml and particle geometry in terms of shape factor and roundness factor.