Orientation Softening as a Mechanism of Ultra-High Molecular Weight Polyethylene (UHMWPE) Wear in Artificial Hip and Knee Joints

2009 ◽  
pp. 56-56-21 ◽  
Author(s):  
A Wang ◽  
B Edwards ◽  
S-S Yau ◽  
VK Polineni ◽  
A Essner ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Knee Joints ◽  
Uhmwpe Wear ◽  
Artificial Hip ◽  
Ultra High Molecular Weight

Effect of Lubricant Protein Concentration on the Wear of Ultra-High Molecular Weight Polyethylene Sliding Against a CoCr Counterface

2003 ◽  
Vol 125 (3) ◽  
pp. 638-642 ◽  
Author(s):  
Vesa Saikko
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Protein Concentration ◽  
Calf Serum ◽  
Wear Testing ◽  
Wear Factor ◽  
Prosthetic Joints ◽  
Uhmwpe Wear ◽  
Pin On Disk ◽  
Ultra High Molecular Weight

In the wear testing of prosthetic joints, the optimal lubricant protein concentration is disputed. The effect of protein concentration of calf serum based lubricant on the wear of ultra-high molecular weight polyethylene against CoCr was studied with a 12-station, circularly translating pin-on-disk device. The wear factor first steeply increased with increasing concentration, reached a peak at 10–20 mg/ml, and then slowly decreased. Below 20 mg/ml, the wear mechanisms were not entirely representative of clinical wear. Above this value, the morphology of the UHMWPE wear surface resembled that of retrieved cups. The results indicated that the concentration should not be below 20 mg/ml. The scope of this recommendation is discussed.

Ultra-High Molecular Weight Polyethylene Wear Debris Generated in Vivo and in Laboratory Tests; the Influence of Counterface Roughness

1996 ◽  
Vol 210 (1) ◽  
pp. 3-10 ◽  
Author(s):  
J L Hailey ◽  
E Ingham ◽  
M Stone ◽  
B M Wroblewski ◽  
J Fisher
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Wear Debris ◽  
Laboratory Tests ◽  
Polyethylene Wear ◽  
Uhmwpe Wear ◽  
Major Variable ◽  
Ultra High Molecular Weight ◽  
Counterface Roughness

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.

Effects of Additives on Oxidation of Ultra High Molecular Weight Polyethylene used for Artificial Knee Joints

2002 ◽  
Vol 2002 (0) ◽  
pp. 437-438
Author(s):  
Syunich Kawano ◽  
Itsuo Sakuramoto ◽  
Akiko Mori ◽  
Kazuya Nagata ◽  
Naohide Tomita ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Knee Joints ◽  
Ultra High Molecular Weight

A Bipolar Artificial Hip Joint Design for Contact Impingement Reduction

2015 ◽  
Vol 1123 ◽  
pp. 164-168 ◽  
Author(s):  
Eko Saputra ◽  
Iwan Budiwan Anwar ◽  
J. Jamari ◽  
Emile van der Heide
Keyword(s):  
Molecular Weight ◽  
Range Of Motion ◽  
High Molecular Weight ◽  
Internal Rotation ◽  
Hip Joint ◽  
Acetabular Liner ◽  
Free Range ◽  
Artificial Hip Joint ◽  
Artificial Hip ◽  
Ultra High Molecular Weight

The acetabular liner of an artificial hip joint (AHJ) is easily damaged locally in case of impingement, i.e. in case of contact of the liner wall with the stem neck, especially when it is made from relatively soft material such as ultra high molecular weight polyethylene (UHMWPE). Frequent impingement will severely damage the acetabular liner, requiring replacement of the AHJ. The aim of this study is to reduce AHJ impingement for specific combinations of flexion, internal rotation, and adduction of the thigh, by optimizing the design of the AHJ. The presented new design is based on modifying a conventional AHJ into a bipolar version with a higher free range of motion (RoM). Results show that the proposed design is able to prevent impingement for RoM. The latter range of motion corresponds well with the requirements of Shalat.

The Cooperative Effects of Protein and Lipid on Wear Behavior of Ultra-High Molecular Weight Polyethylene

2005 ◽  
Author(s):  
Y. Sawae ◽  
T. Murakami
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Lipid Content ◽  
Lipid Composition ◽  
Wear Behavior ◽  
Wear Test ◽  
Cooperative Effects ◽  
Uhmwpe Wear ◽  
Ultra High Molecular Weight ◽  
Wear Tests

The cooperative effects of protein and lipid on the wear behavior of ultra-high molecular weight polyethylene (UHMWPE) was examined in laboratory wear tests with a multidirectional sliding pin-on-plate wear tester. Results indicated that the protein and lipid composition of lubricant used in the wear test had substantial effects on the wear behavior of UHMWPE sliding against a metal counter face. Not only the amount of protein and lipid content but also a preparation procedure of the lubricant might affect the UHMWPE wear.

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