Binding of proteins to ultra high molecular weight polyethylene wear particles as a possible mechanism of macrophage and lymphocyte activation

2010 ◽  
Vol 95A (3) ◽  
pp. 950-955 ◽  
Author(s):  
E. Zolotarevová ◽  
J. Hudeček ◽  
M. Špundová ◽  
G. Entlicher
Author(s):  
P Campbell ◽  
P Doom ◽  
F Dorey ◽  
H C Amstutz

The wear rate of ultra-high molecular weight polyethylene total hip replacement components is known to be influenced by various factors such as material and design. However, it is not known if these factors affect the size or morphology of the wear particles. The aim of this study was to compare the polyethylene wear particles from hip replacements of differing bearing materials and designs. Tissues were obtained at the revision surgeries of patients with surface replacements with titanium alloy or cobalt-chrome alloy femoral components up to 51 mm in diameter, and stem-type hip replacements with cobalt-chrome or alumina ceramic femoral components that were 28 or 32 mm in diameter. The polyethylene particles were isolated following tissue digestion and density gradient separation, and then studied by scanning electron microscopy. A computerized image analysis system was used to measure the diameter and length of the particles. The majority of wear particles were submicron in diameter. No systematic differences in size and morphology were found between the groups in this study. The similarity in size and morphology of the wear particles suggested that the same basic wear mechanisms were occurring in these components.


Author(s):  
J L Hailey ◽  
E Ingham ◽  
M Stone ◽  
B M Wroblewski ◽  
J Fisher

The objective of this study was to investigate the effect of counterface roughness and lubricant on the morphology of ultra-high molecular weight polyethylene (UHMWPE) wear debris generated in laboratory wear tests, and to compare this with debris isolated from explanted tissue. Laboratory tests used UHMWPE pins sliding against stainless steel counterfaces. Both water and serum lubricants were used in conjunction with rough and smooth counterfaces. The lubricants and tissue from revision hip surgery were processed to digest the proteins and permit filtration. This involved denaturing the proteins with potassium hydroxide (KOH), sedimentation of any remaining proteins, and further digestion of these proteins with chromic acid. All fractions were then passed through a 0.2 μm membrane, and the debris examined using scanning electron microscopy. The laboratory studies showed that the major variable influencing debris morphology was counterface roughness. The rougher counter-faces produced larger numbers of smaller particles, with a size range extending below 1 μm. For smooth counterfaces there were fewer of these small particles, and evidence of larger platelets, greater than 10 μm in diameter. Analysis of the debris from explanted tissues showed a wide variation in the particle size distribution, ranging from below 1 μm up to several millimetres in size. Of major clinical significance in relation to osteolysis and loosening is roughening of the femoral components, which may lead to greater numbers of the sub-micron-sized particles.


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