0000000000046837
AUTHOR
Hans Hely
Der HEPFIEx-Simulator, eine Apparatur zur Bestimmung der Reibzahlen zwischen Hüftkopf-Prothesen und Knorpel / The HEPFlEx Simulator, a Device for Measuring the Friction between Femoral Head Prostheses and Cartilage
We describe a device designed to investigate friction between various femoral head prostheses and human acetabula. It enables not only the determination of friction and the relevance of the play between the femoral head and acetabulum, but also the evaluation of the kinematic behaviour of bipolar prostheses. In the simulator, the various femoral head prostheses are placed on a special cone and tested against a human cadaveric acetabulum. The swiveling range of the device is uniaxial, and the swiveling angle is +/- 35 degrees. The maximum force produced pneumatically is 5kN. Testing of the simulator with a TEP was successful and friction-coefficients of < 0.1 were measured, as are reported i…
Are there any differences in various polyaxial locking systems? A mechanical study of different locking screws in multidirectional angular stable distal radius plates.
Numerous angular stable plates for the distal radius exist, and technically based comparisons of the polyaxial locking interfaces are lacking. The aim of this mechanical study was to investigate three different locking interfaces of angular stable volar plates by cantilever bending: VA-LCP Two-Column Distal Radius Plates 2.4 mm (Synthes® GmbH, Oberdorf, Switzerland), IXOS® P4 (Martin, Tuttlingen, Germany) and VariAX™ (Stryker®, Duisburg, Germany). We assessed the strength of 0°, 5°, 10° and 15° screw locking angles and tested the bending strength from 10° to 5° angles by cyclic loading until breakage. The final setup repeated the above assessments by inclusion of four locking screws. The si…