title: Adhesive strength of total knee endoprostheses to bone cement - analysis of metallic and ceramic femoral components under worst-case conditions.
abstract: Evaluation of the adhesive strength of femoral components to the bone cement is a relevant parameter for predicting implant safety. In the present experimental study, three types of cemented femoral components (metallic, ceramic and silica/silane-layered ceramic) of the bicondylar Multigen Plus knee system, implanted on composite femora were analysed. A pull-off test with the femoral components was performed after different load and several cementing conditions (four groups and n=3 components of each metallic, ceramic and silica/silane-layered ceramic in each group). Pull-off forces were comparable for the metallic and the silica/silane-layered ceramic femoral components (mean 4769 N and 4298 N) under standard test condition, whereas uncoated ceramic femoral components showed reduced pull-off forces (mean 2322 N). Loading under worst-case conditions led to decreased adhesive strength by loosening of the interface implant and bone cement using uncoated metallic and ceramic femoral components, respectively. Silica/silane-coated ceramic components were stably fixed even under worst-case conditions. Loading under high flexion angles can induce interfacial tensile stress, which could promote early implant loosening. In conclusion, a silica/silane-coating layer on the femoral component increased their adhesive strength to bone cement. Thicker cement mantles (>2 mm) reduce adhesive strength of the femoral component and can increase the risk of cement break-off.
authors.forename: Philipp
authors.initials: P
authors.lastname: Bergschmidt
authors.forename: Rebecca
authors.initials: R
authors.lastname: Dammer
authors.forename: Carmen
authors.initials: C
authors.lastname: Zietz
authors.forename: Susanne
authors.initials: S
authors.lastname: Finze
authors.forename: Wolfram
authors.initials: W
authors.lastname: Mittelmeier
authors.forename: Rainer
authors.initials: R
authors.lastname: Bader
mesh_terms: D000269:Adhesives / Q000737:chemistry*; D019645:Arthroplasty, Replacement, Knee / Q000592:standards*; D001843:Bone Cements / Q000737:chemistry / Q000592:standards*; D002516:Ceramics / Q000737:chemistry / Q000592:standards*; D020099:Coated Materials, Biocompatible / Q000737:chemistry; D006801:Humans; D007720:Knee Prosthesis / Q000592:standards*; D011474:Prosthesis Design / Q000592:standards*; D012822:Silicon Dioxide / Q000737:chemistry*; D013718:Tensile Strength
chemical_list: D000269:Adhesives; D001843:Bone Cements; D020099:Coated Materials, Biocompatible; D012822:Silicon Dioxide