Components that are snapped together or have some other type of interlocking mechanism (e.g., tibial bearing/tray, metal-backed patella, Morse taper) must be able to survive physiological loads. To characterize the strength of attachment between the tibial bearing and tibial baseplate or tray for both types of prostheses, the FDA recommends that you perform the following tests: static anterior and posterior shear testing static medial and lateral shear testing static tensile pull-off testing. For a metal-backed patella component of a total knee prosthesis, FDA recommends that you provide a complete test report of: static tensile pull-off testing shear fatigue testing. Static tensile pull-off testing determines the tensile force required to separate the UHMWPe bearing from the metal backing. Shear fatigue testing of metal-backed patellar components determines the expected lifetime of the device. Refer to ASTM F1672 for information on relevant failure modes and test methods. The FDA recommends testing five samples at various loads to develop an AF/N curve with at least one sample surviving 10 million cycles.
Applicable Testing Standards
Recommended Test Machine
Static and fatigue forces up to 50 kN (11,250 lbf)
Frequency ratings up to 75 Hz
Oil-free, all electric actuator for clean test conditions
Lower purchase, operating, and maintenance costs than hydraulic equivalents
