Contact stresses in lumbar total disc arthroplasty.
Total disc arthroplasty is gaining in popularity as an alternative to spinal fusion. A total disc consists of articulating bearing surfaces with one made from a metal and the other made from either a metal or a polymer. The aim of this study was to determine the contact stresses in lumbar total disc arthroplasty devices. The total disc was modelled as a ball and socket joint and Hertzian contact theory was used to determine the maximum contact stresses. The effect of material combination and implant size on contact stress was investigated. For a typical disc arthroplasty with a ball radius of 14 mm, the contact stresses for metal against polymer and metal against metal material combinations were 3 to 6 MPa and 63-130 MPa, respectively, and were below the fatigue strength of the materials.
Wenzel
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Department of Mechanical and Manufacturing Engineering, University of Birmingham, Edgbaston, Birmingham, UK.
Shepherd
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D001178:Arthroplasty / Q000295:instrumentation* / Q000379:methods*; D019245:Compressive Strength; D003198:Computer Simulation; D017076:Computer-Aided Design; D017586:Diskectomy / Q000379:methods*; D019544:Equipment Failure Analysis; D006801:Humans; D007595:Joint Prosthesis; D008159:Lumbar Vertebrae / Q000502:physiology* / Q000601:surgery*; D008954:Models, Biological; D011312:Pressure; D011474:Prosthesis Design; D016896:Treatment Outcome; D016474:Weight-Bearing