title: Influence of various types of damage on the fracture strength of ceramic femoral heads.
abstract: Ceramic-on-ceramic articulations are a frequently used bearing for total hip replacements. This success mainly is due to their excellent tribological properties. Ceramics can withstand high pressure loads due to its brittleness but only low bending stresses. A ceramic ball head fracture is the result of subcritical crack growth. This kind of fracture in vivo can abet by damage or contamination of the stem cone. The main goal of this work is to provide a risk assessment of different possible damage mechanisms and contaminations that may result in lower fracture strength of a ceramic ball head. To simulate potential causes, different types and dimensions of metal wire, foils, hair, and lubricants were inserted between the ceramic ball head and the metal cone of the stem. The test results clearly show that fracture strength is negatively influenced by most of the inhomogeneities between the cone and the head because they increase the peak stresses acting on a part of the ceramic ball head. The results of this article clearly confirm the demand for an undamaged taper fit "free of contamination" between the ceramic head and the metal cone during implantation.
authors.affiliation: Centre of Excellence Ceramics, Mathys Orthopaedie GmbH, Germany. viola.wuttke@mathysmedical.com
authors.forename: Viola
authors.initials: V
authors.lastname: Wuttke
authors.forename: Hartmut
authors.initials: H
authors.lastname: Witte
authors.forename: Katrin
authors.initials: K
authors.lastname: Kempf
authors.forename: Thomas
authors.initials: T
authors.lastname: Oberbach
authors.forename: Daniel
authors.initials: D
authors.lastname: Delfosse
mesh_terms: D002516:Ceramics / Q000737:chemistry*; D019245:Compressive Strength; D019544:Equipment Failure Analysis; D005270:Femur Head / Q000503:physiopathology* / Q000601:surgery*; D006622:Hip Prosthesis; D006801:Humans; D008422:Materials Testing; D011475:Prosthesis Failure; D013718:Tensile Strength