title: Wear in metal-on-metal total disc arthroplasty.
abstract: The wear of a model metal-on-metal ball-and-socket total disc arthroplasty was measured in a simulator. The ball had a radius of 10 mm, and there was a radial clearance between ball and socket of 0.015 mm. The model was subjected to simultaneous flexion-extension, lateral bending, axial rotation (frequency: 1 Hz) and compression (frequency: 2 Hz, maximum load: 2 kN). Throughout the tests, the models were immersed in calf serum diluted to a concentration of 15 g protein per litre, at a controlled temperature of 37 °C. Tests were performed on three models. At regular intervals (0, 0.5, 1, 2, 3, 4 and 5 million cycles), mass and surface roughness were determined; mass measurements were converted into the volume lost as a result of wear. All measurements were repeated six times. Wear occurred in two stages. In the first stage (duration about 1 million cycles), there was a linear wear rate of 2.01 ± 0.04 mm(3) per million cycles; in the second stage, there was a linear wear rate of 0.76 ± 0.02 mm(3) per million cycles. Surface roughness increased linearly in the first million cycles and then continued to increase linearly but more slowly.
authors: School of Mechanical Engineering, University of Birmingham, Birmingham, UK.
authors: Parshia
authors: P
authors: Moghadas
authors: Aziza
authors: A
authors: Mahomed
authors: David W l
authors: DW
authors: Hukins
authors: Duncan E T
authors: DE
authors: Shepherd
mesh_terms: D003198:Computer Simulation; D008422:Materials Testing; D008670:Metals / Q000737:chemistry*; D015233:Models, Statistical; D011474:Prosthesis Design; D013124:Spinal Injuries / Q000628:therapy; D013499:Surface Properties; D013696:Temperature; D019415:Torque; D059145:Total Disc Replacement / Q000295:instrumentation / Q000379:methods*
chemical_list: D008670:Metals
keywords: Ball-and socket; metal-on-metal; total disc arthroplasty; wear