Computational Wear Simulation on Cross-linked Ultra-high Molecular Weight Polyethylene Artificial Hip Joints

There is considerable interest in the wear of polyethylene and the resulting wear-debrisinduced osteolysis in artificial hip joints. Proteins play an important role as boundary lubricants in vivo in the pseudosynovial fluid, and these are reproduced in in vitro tests through the use of bovine serum. Little is known, however, about the effect of phospholipid concentrations within proteinaceous solutions on the wear of ultra-high molecular weight polyethylene (UHMWPE). The effects of protein-containing lubricants with 0.05, 0.5 and 5 per cent (w/v) phosphatidyl choline concentrations on the wear of ultra-high molecular weight polyethylene (UHMWPE) were compared with 25 per cent (v/v) bovine serum which had 0.01 per cent (w/v) lipid; the effects were compared in a hip joint simulator with smooth (n = 4) and scratched (n = 3) femoral heads. The control bovine serum lubricant produced UHWMPE wear of 55 and 115mm3/106 cycles on the smooth and rough heads respectively. The increased phospholipid concentration significantly reduced the wear rate. At the higher concentration (5% w/v phosphatidyl choline) the average wear was reduced to less than 2 mm3/106 cycles. Even with the relatively low concentrations of 0.05% w/v phosphatidyl choline the wear was reduced by at least threefold compared with the bovine serum tests for both the smooth and rough femoral heads. There may be considerable differences in the phospholipid concentrations in patients' synovial fluid and this is highly likely to produce considerable variation in wear rates. In vitro, differences in the phospholipid concentration of lubricants may also cause variation in wear rates between different simulator tests.

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A multi-station hip joint simulator study of the performance of 22 mm diameter zirconia-ultra-high molecular weight polyethylene total replacement hip joints

Proceedings of the Institution of Mechanical Engineers Part H Journal of Engineering in Medicine ◽

10.1243/0954411991534825 ◽

1999 ◽

Vol 213 (2) ◽

pp. 77-90 ◽

Cited By ~ 39

Author(s):

A A J Goldsmith ◽

D Dowson

Keyword(s):

Molecular Weight ◽

High Molecular Weight ◽

Hip Joint ◽

Hip Joints ◽

Total Replacement ◽

Simulator Study ◽

Ultra High Molecular Weight ◽

Hip Joint Simulator

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Computational Wear Simulation of Artificial Hip Joints

Encyclopedia of Tribology ◽

10.1007/978-0-387-92897-5_100228 ◽

2013 ◽

pp. 425-425

Keyword(s):

Wear Simulation ◽

Hip Joints ◽

Artificial Hip ◽

Artificial Hip Joints

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A Bipolar Artificial Hip Joint Design for Contact Impingement Reduction

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1123.164 ◽

2015 ◽

Vol 1123 ◽

pp. 164-168 ◽

Cited By ~ 6

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.

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