Comparison ofin vitro within vivo characteristics of wear particles from metal-metal hip implants

2004 ◽  
Vol 70B (2) ◽  
pp. 167-178 ◽  
Author(s):  
Isabelle Catelas ◽  
John B. Medley ◽  
Pat A. Campbell ◽  
Olga L. Huk ◽  
J. Dennis Bobyn
Keyword(s):  
Wear Particles ◽  
Hip Implants ◽  
Metal Metal

scholarly journals IRAK-4 in macrophages contributes to inflammatory osteolysis of wear particles around loosened hip implants

2021 ◽  
pp. 175342592110187
Author(s):  
Yang-chun Zhang ◽  
Jian-hong Xiao ◽  
Shao-jie Deng ◽  
Guo-liang Yi
Keyword(s):  
Endotoxin Tolerance ◽  
Wear Particles ◽  
Hip Implants ◽  
Prosthesis Loosening ◽  
Specific Mechanism ◽  
Local Immunity ◽  
Tnf Α ◽  
Local Inflammatory Reaction ◽  
Pro Inflammatory Cytokines

TLRs recognizing PAMPS play a role in local immunity and participate in implant-associated loosening. TLR-mediated signaling is primarily regulated by IL-1 receptor associated kinase-M (IRAK-M) negatively and IRAK-4 positively. Our previous studies have proved that wear particles promote endotoxin tolerance in macrophages by inducing IRAK-M. However, whether IRAK-4 is involved in inflammatory osteolysis of wear particles basically, and the specific mechanism of IRAK-4 around loosened hip implants, is still unclear. IRAK-4 was studied in the interface membranes from patients in vivo and in particle-stimulated macrophages to clarify its role. Also, IL-1β and TNF-α levels were measured after particle and LPS stimulation in macrophages with or without IRAK-4 silenced by siRNA. Our results showed that the interface membranes around aseptic and septic loosened prosthesis expressed more IRAK-4 compared with membranes from osteoarthritic patients. IRAK-4 in macrophages increased upon particle and LPS stimulation. In the former, IL-1β and TNF-α levels were lower compared with those of LPS stimulation, and IRAK-4 siRNA could suppress production of pro-inflammatory cytokines. These findings suggest that besides IRAK-M, IRAK-4 also plays an important role in the local inflammatory reaction and contributes to prosthesis loosening.

Kinematics of the MATCO™ hip simulator and issues related to wear testing of metal-metal implants

1997 ◽  
Vol 211 (1) ◽  
pp. 89-99 ◽  
Author(s):  
J B Medley ◽  
J J Krygier ◽  
J D Bobyn ◽  
F W Chan ◽  
A Lippincott ◽  
...  
Keyword(s):  
Film Thickness ◽  
Contact Zone ◽  
Elastohydrodynamic Lubrication ◽  
Hertzian Contact ◽  
Wear Testing ◽  
Circular Path ◽  
Hip Implants ◽  
Hip Simulator ◽  
Metal Metal

Metal-metal hip implants have been used clinically in Europe to reduce the risk of wear particle induced osteolysis. Joint simulator devices could provide useful information for design improvement of the modern generation of metal-metal hip implants. Early wear results for metal-metal hip specimens were obtained using a MATCO™ hip simulator. A detailed kinematic analysis was developed for the MATCO™ simulator and applied to two of the wear experiments to predict the starting surface motion, contact zone and lubricant film thickness. It was shown that points on cup surfaces were not subjected to a reciprocating interaction with the head during wear at the beginning of testing but as wear proceeded, it was suggested that, in some cases, reciprocating interaction did occur on the cup surface. Comparison between simulator and in vivo kinematics suggested a more realistic representation for cup than for head wear. In the simulator, the Hertzian contact zone moved in a circular path over the cup surface and changed in size in correspondence with the applied load. Elastohydrodynamic lubrication was considered to be possible in the simulator, with estimated fluid film thickness as great as 0.1 μm. However, such thick films were not likely to have occurred at the start of the two wear tests which were examined in detail, although some mixed film lubrication might have accounted for the relatively low wear of one of the specimens. The inclusion of kinematic details, contact mechanics and elastohydrodynamic lubrication analysis in simulator testing protocols and in design of metal-metal hip implants was recommended.

scholarly journals Methods for Sterilizing Clinically Relevant Wear Particles Isolated from Metal-on-Metal Hip Implants

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Ernest S. Fung ◽  
Kenneth M. Unice ◽  
Dennis J. Paustenbach ◽  
Brent L. Finley ◽  
Michael Kovochich
Keyword(s):  
Wear Particles ◽  
Hip Implants ◽  
Metal On Metal
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