The doctoral dissertations of the former Helsinki University of Technology (TKK) and Aalto University Schools of Technology (CHEM, ELEC, ENG, SCI) published in electronic format are available in the electronic publications archive of Aalto University - Aaltodoc.
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Effect of Lubricant on the Wear of Prosthetic Joint Materials

Tiina Ahlroos

Dissertation for the degree of Doctor of Science in Technology to be presented with due permission for public examination and debate in Auditorium K216 at Helsinki University of Technology (Espoo, Finland) on the 28th of November, 2001, at 12 o'clock noon.

Overview in PDF format (ISBN 951-22-5898-6)   [70 KB]
Dissertation is also available in print (ISBN 951-666-581-0)

Abstract

The wear of ultra-high molecular weight polyethylene (UHMWPE) in prosthetic hip and knee joints is a significant clinical problem. The wear particles cause inflammatory tissue reactions which may lead to osteolysis and loosening of the implant fixation. The effect of lubricant on the wear of polyethylene was studied with a reciprocating pin-on-flat (RPF) apparatus, uniaxial (HUT-2) and three-axis (HUT-3) hip joint simulators, circularly translating pin-on-disk (CTPOD) device, biaxial rocking motion (BRM-1 and BRM-2) hip wear simulators, and a three-axis ball-on-flat (BOF) knee wear simulator. The aim was to produce wear similar to that known to occur clinically. To accomplish this, the basic criteria for the lubricant were: 1) no polyethylene transfer layer should form on the metal counterface, 2) the bearing surface of the polyethylene should become burnished, 3) the wear particle size should be of the order of 1 μm, and 4) the wear factor should be of the order of 1 x 10-6 mm3/Nm. The lubricants studied were human prosthetic joint fluid, bovine and calf serum, bovine albumin and gamma-globulin, soybean lecithin, dipalmitoylphosphatidylcholine (DPPC), soy protein, and distilled water. The counterfaces of polyethylene were CoCr, stainless steel, alumina, and diamondlike carbon (DLC). All the criteria were met by bovine and calf serum, albumin and gamma-globulin. Hence, albumin and gamma-globulin proved to be the crucial fractions of serum and synovial fluid with respect to producing clinically relevant wear of polyethylene. In conclusion, realistic wear was produced when the direction of sliding constantly changed relative to the polyethylene specimen, and a protein-based lubricant was used.

This thesis consists of an overview and of the following 6 publications:

  1. Saikko, V., Ahlroos, T., Phospholipids as boundary lubricants in wear tests of prosthetic joint materials. Wear Vol. 207 (1997), p. 86-91.
  2. Ahlroos, T., Saikko, V., Wear of prosthetic joint materials in various lubricants. Wear Vol. 211 (1997), p. 113-119.
  3. Saikko, V., Ahlroos, T., Type of motion and lubricant in wear simulation of polyethylene acetabular cup. Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine Vol. 213 (1999), p. 301-310.
  4. Saikko, V., Ahlroos, T., Wear simulation of UHMWPE for total hip replacement with a multidirectional motion pin-on-disk device: Effects of counterface material, contact area, and lubricant. Journal of Biomedical Materials Research Vol. 49 (2000), p. 147-154.
  5. Saikko, V., Ahlroos, T., Calonius, O., Keränen, J., Wear simulation of total hip prostheses with polyethylene against CoCr, alumina and diamond-like carbon. Biomaterials Vol. 22 (2001), p. 1507-1514.
  6. Saikko, V., Ahlroos, T., Calonius, O., A three-axis knee wear simulator with ball-on-flat contact. Wear Vol. 249 (2001), p. 310-315.

Keywords: prosthetic joint, hip joint, knee joint, lubricant, polyethylene, wear

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© 2002 Helsinki University of Technology

Last update 2011-05-26