Friction in metal-on-metal total disc arthroplasty: Effect of ball radius

P Moghadas, Aziza Mahomed, David Hukins, Duncan Shepherd

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)
333 Downloads (Pure)


Total Disc Arthroplasty (TDA) can be used to replace a degenerated intervertebral disc in the spine. There are different designs of prosthetic discs, but one of the most common is a ball-and-socket combination. Contact between the bearing surfaces can result in high frictional torque, which can then result in wear and implant loosening. This study was designed to determine the effects of ball radius on friction. Generic models of metal-on-metal TDA were manufactured with ball radii of 10, 12, 14 and 16 mm, with a radial clearance of 0.015 mm. A simulator was used to test each sample in flexion-extension, lateral bending and axial rotation at frequencies of 0.25, 0.5, 0.75, 1, 1.25, 1.5, 1.75 and 2 Hz under loads of 50, 600, 1200 and 2000 N, in new born calf serum. Frictional torque was measured and Stribeck curves were plotted to illustrate the lubrication regime in each case. It was observed that implants with a smaller ball radius showed lower friction and showed boundary and mixed lubrication regimes, whereas implants with larger ball radius showed boundary lubrication only. This study suggests designing metal-on-metal TDAs with ball radius of 10 or 12 mm, in order to reduce wear and implant loosening.
Original languageEnglish
Pages (from-to)504-509
JournalJournal of Biomechanics
Issue number3
Publication statusPublished - 15 Dec 2011


Dive into the research topics of 'Friction in metal-on-metal total disc arthroplasty: Effect of ball radius'. Together they form a unique fingerprint.

Cite this