ISO 7206-12 Deformation test method for acetabular shells
The ISO 7206-12 standard describes a test method and test requirements for determining the short-term deformation of a press-fit acetabular component for hip joint replacements.
Press-fit is a common method for cement-free fixation of acetabular shells. The difference in diameter between the acetabular shell and the roughened acetabular base determines the degree of fixation or the pressure between the bone and the acetabular components. However, this pressure also leads to deformation of both the bone and the acetabular shell. The deformation of the acetabular shell can affect the correct fit and the lubrication and friction properties of the joint surfaces. This leads to increased wear and can result in premature failure of the implant.
ISO 7206-12 applications
- The test method is used to determine short-term deformation of a press-fit acetabular component under specific laboratory conditions
- The short-term deformation of the acetabular component should not significantly impair the functional properties of the prosthesis system
- The standard itself does not describe a quantitative deformation limit. However, it specifies the most important test parameters and describes the test setup
- The test method enables the comparison of different designs and materials
ISO 7206-12 principle and procedure
- The acetabular shell is subjected to diametrically opposed two-point loading
- To determine the short-term deformation, the diameter is measured before, during and after loading
- The process is repeated two more times. The acetabular component is rotated by 120° in order to take into account the influence of asymmetric design features such as fins and holes
- At least three acetabular shells should be tested
ISO 7206-12 testing at ZwickRoell
- ZwickRoell offers numerous testing systems for tests in accordance with ISO 7206-12—from a static testing machine to the LTM electrodynamic testing machine and servohydraulic testing systems—everything is possible
- For the two-point loading, the acetabular shell specimen is positioned between two compression platens
- The diameter is typically measured using an external displacement measuring system, which can be quickly and easily integrated into our testXpert testing software via a 0-10 V interface
- A standard test program, which already contains all the requirements of the standard for the test sequence or the test report, is available to perform the test.
