Tribological Testing of Articular Cartilage

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Tribological Testing of Articular Cartilage
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Material Pair

• Bovine metacarpal-phalangeal joint
• Core taken from metacarpal bone to be
  reciprocated against the proximal sesamoid bone
• Synovial fluid used as the lubricant

Core taken from head of metacarpal bone
Mounted sesamoid bone
Proximal sesamoid bone
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Device Design

• Dead-weighted design
• Weight loaded into Teflon cup which is allowed to
  freely slide vertically in the aluminum shell

Shell 6061-T6 Aluminum
Core Holder
Teflon Cup
Base Plate 6061-T6 Aluminum
Direction of Motion
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Constructed Apparatus
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Example Friction Plots

• 0.25 Hz Frequency, 0.5 cm amplitude for 30 cycles
• Position and lateral friction force curves plotted

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Results of Preliminary Testing
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Results of Preliminary Testing

• Dynamic friction
• µk 0.043-0.052
• Under an applied load of 4.47 N (or 2 MPa)
• Over a wide range of frequencies (0.25 - 1 Hz)
• Comparable to literature values (µk 0.05)
• Fisher, J. Northwood, E. A multi-directional in
  vitro investigation into friction, damage and
  wear of innovative chondroplasty materials
  Journal of Clinical Biomechanics, 22 (2007)
  834842
• Static friction
• Estimated to be µs 0.002

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Future Testing

• Applicable for the testing other tribological
  parameters
• contact pressure
• wear
• Design is adaptable
• native cartilage against native cartilage
• biphasic construct against native cartilage
• biphasic construct against biphasic construct