Investigation on stick phenomena in metal-on-metal hip joints after resting periods

Insufficient understanding of tribological behaviour in total joint arthroplasty is considered as one of the reasons for prosthesis failure. Contrary to the continuous motion input profiles of hip simulators, human locomotion contains motion interruptions. These occurring resting periods can cause stick phenomena in metal-on-metal hip joints. The aim of the present study was to investigate the tribological sensitivity of all-metal bearings to motion interruptions on in vitro test specimens and retrieved implants. Friction and wear with and without resting periods were quantified. Unlike the metal-on-polyethylene joints, the static friction of metal-on-metal joints increased up to micros = 0.3 with rest, while wear appeared to be unaffected. This effect is caused by the interlocking of firmly adhered carbon layers, which were generated from the protein-containing lubricant through tribochemical reactions. Since more than 80 per cent of the retrieved implants exhibited macroscopically visible carbon layers, the increase in friction presumably also occurs under physiological conditions, which is then transferred to the bone-implant interface. These recurrent tangential stress peaks should be considered for the design features of the cup-bone interface, in particular when larger-sized implant heads are used.

Subjects

Biocompatible Materials

Equipment Failure Analysis

Friction

Lubrication

Materials Testing

Particle Size

Prosthesis Design

Surface Properties

Time Factors

Vitallium

Hip Prosthesis

Prosthesis Failure

DDC Class

610: Medizin

Lizenz

http://rightsstatements.org/vocab/InC/1.0/

Name

09544119jeim117.pdf

Size

214.69 KB

Format

Adobe PDF

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Investigation on stick phenomena in metal-on-metal hip joints after resting periods