Standard Practice for Fretting Corrosion Testing of Modular Implant Interfaces: Hip Femoral Head-Bore and Cone Taper Interface
1Key Takeaways
5.1 The modular interfaces of total joint prostheses are subjected to micromotion that could result in fretting and corrosion. The release of corrosion products and particulate debris could stimulate adverse biological reactions, as well as lead to accelerated wear at the articulation interface. Methods to asse…
2Scope / Description
5.1 The modular interfaces of total joint prostheses are subjected to micromotion that could result in fretting and corrosion. The release of corrosion products and particulate debris could stimulate adverse biological reactions, as well as lead to accelerated wear at the articulation interface. Methods to assess the stability and corrosion resistance of the modular interfaces, therefore, are an essential component of device testing.
5.2 Long-term in-vitro testing is essential to produce damage and debris from fretting of a modular interface (4,5). The use of proteinaceous solutions is recommended to best simulate the in-vivo environment.
5.3 Short-term tests often can be useful in evaluations of differences in design during device development (1-4). The electrochemical methods provide semiquantitative measures of fretting corrosion rates. The relative contributions of mechanical and electrochemical processes to the total corrosion and particulate release phenomena, however, have not been established; therefore, these tests should not be utilized to compare the effects of changes in material combinations, but rather be utilized to evaluate design changes of bore (head) and cone (stem) components.
5.4 These tests are recommended for evaluating the fretting wear and corrosion of modular interfaces of hip femoral head and stem components. Similar methods may be applied to other modular interfaces where fretting corrosion is of concern.
5.5 These methods are recommended for comparative evaluation of the fretting wear and corrosion of new materials, coatings, or designs, or a combination thereof, under consideration for hip femoral head and neck modular interfaces. Components for testing may be those of a manufactured modular hip device (finished product) or sample coupons, which are designed and manufactured for simulation of the head, taper, and neck region of a modular hip device.
1.1 This practice describes the testing, analytical, and characterization methods for evaluating the mechanical stability of the bore and cone interface of the head and stem junction of modular hip implants subjected to cyclic loading by measurements of fretting corrosion (1-5).2 Two test methods described are as follows:
1.1.1 Method I—The primary purpose of this method is to provide a uniform set of guidelines for long-term testing to determine the amount of damage by measureme......