title: Bone stresses before and after insertion of two commercially available distal ulnar implants using finite element analysis.
abstract: Distal ulnar arthroplasty is becoming a popular treatment option for disorders of the distal radioulnar joint; however, few studies have investigated how load transfer in the ulna is altered after insertion of an implant. The purpose of our study was to compare bone stresses before and after insertion of two commercially available cemented distal ulnar implants: an implant with a titanium stem and an implant with a cobalt chrome stem. Appropriately sized implants of both types were inserted into eight previously validated subject-specific finite element models, which were created by using information derived from computed tomography scans. The von Mises stresses were compared at eight different regions pre- and post-implantation. The bone stresses with the titanium stem were consistently closer to the pre-implantation stresses than with the cobalt chrome stem. For the loading situation and parameters investigated, results of these models show that insertion of the E-Centrix® ulnar Head may result in less stress shielding than the SBI uHead™ stem. Future studies are required to investigate other implant design parameters and loading conditions that may affect the predicted amount of stress shielding.
authors.affiliation: Jack McBain Biomechanical Testing Laboratory, Department of Mechanical and Materials Engineering, The University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 5B9, Canada.
authors.forename: Rebecca L
authors.initials: RL
authors.lastname: Austman
authors.forename: Graham J W
authors.initials: GJ
authors.lastname: King
authors.forename: Cynthia E
authors.initials: CE
authors.lastname: Dunning
mesh_terms: D000497:Alloys; D019643:Arthroplasty, Replacement; D002102:Cadaver; D002857:Chromium; D003035:Cobalt; D020342:Finite Element Analysis; D006801:Humans; D008422:Materials Testing; D019736:Prostheses and Implants; D011474:Prosthesis Design; D019919:Prosthesis Implantation; D013314:Stress, Mechanical; D014025:Titanium; D014457:Ulna / Q000503:physiopathology / Q000601:surgery*; D016474:Weight-Bearing
chemical_list: D000497:Alloys; D002857:Chromium; D003035:Cobalt; D014025:Titanium