title: Manufacturing conditioned roughness and wear of biomedical oxide ceramics for all-ceramic knee implants.
abstract: BACKGROUND
  Ceramic materials are used in a growing proportion of hip joint prostheses due to their wear resistance and biocompatibility properties. However, ceramics have not been applied successfully in total knee joint endoprostheses to date. One reason for this is that with strict surface quality requirements, there are significant challenges with regard to machining. High-toughness bioceramics can only be machined by grinding and polishing processes. The aim of this study was to develop an automated process chain for the manufacturing of an all-ceramic knee implant.
  
  
  METHODS
  A five-axis machining process was developed for all-ceramic implant components. These components were used in an investigation of the influence of surface conformity on wear behavior under simplified knee joint motion.
  
  
  RESULTS
  The implant components showed considerably reduced wear compared to conventional material combinations. Contact area resulting from a variety of component surface shapes, with a variety of levels of surface conformity, greatly influenced wear rate.
  
  
  CONCLUSIONS
  It is possible to realize an all-ceramic knee endoprosthesis device, with a precise and affordable manufacturing process. The shape accuracy of the component surfaces, as specified by the design and achieved during the manufacturing process, has a substantial influence on the wear behavior of the prosthesis. This result, if corroborated by results with a greater sample size, is likely to influence the design parameters of such devices.
authors.affiliation: Institute of Production Engineering and Machine Tools (IFW), Gottfried Wilhelm Leibniz Universität Hannover, An der Universität 2, 30823 Garbsen, Germany. turger@ifw.uni-hannover.de.
authors.forename: Anke
authors.initials: A
authors.lastname: Turger
authors.forename: Jens
authors.initials: J
authors.lastname: Köhler
authors.forename: Berend
authors.initials: B
authors.lastname: Denkena
authors.forename: Tomas A
authors.initials: TA
authors.lastname: Correa
authors.forename: Christoph
authors.initials: C
authors.lastname: Becher
authors.forename: Christof
authors.initials: C
authors.lastname: Hurschler
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D002516:Ceramics / Q000737:chemistry*; D007720:Knee Prosthesis; D008422:Materials Testing / Q000379:methods*; D010087:Oxides / Q000737:chemistry*; D011474:Prosthesis Design / Q000379:methods*; D013499:Surface Properties
chemical_list: D001672:Biocompatible Materials; D010087:Oxides