Knee replacements are among the top surgical procedures worldwide for improving quality of life. Fatigue fracture of knee tibial trays is one of the most commonly reported failure mechanisms of total knee replacements (TKR). It is caused by the loss of underlying bone support resulting from biological reactions, such as wear-induced osteolysis. Under these conditions, the tibial tray becomes mechanically unstable, and cyclic loading imparted by normal walking causes fatigue cracks, ultimately leading to catastrophic failure.
The ElectroPuls™ All-Electric Dynamic Test Instrument assists designers, manufacturers, and researchers through the product life-cycle process, from deriving fundamental material properties, such as resistance to fatigue crack propagation, to testing the entire tibial tray and beyond. We use a clamping fixture to secure one half of the tibial tray, simulating a fully supported condyle. The other unsupported condyle is then subjected to physiologically representative loading. By using our unique Dynacell™ load cell, dynamic inertial errors, such as those caused by the fixturing and from hydro-dynamics that result when testing in an environmental bath, can be removed. This allows for a more accurate measurement of load being applied to the specimen.