Fatigue Testing of Oxinium Femoral Components Fatigue strength the same as for Co-cr devices Supports 4.4kN(1000 lbf in 10 Mcycle fatigue test. Tested worst-case: thin condyle, no bone, full flexion. Image removed due to copyright considerations *tsai et a. sFb 2001
Fatigue Testing of Oxinium Femoral Components • Fatigue strength the same as for Co Fatigue strength the same as for Co -Cr devices. Cr devices. • Supports 4.4 Supports 4.4 kN (1000 lbf) in 10 ) in 10 Mcycle fatigue test. fatigue test. • Tested worst Tested worst-case: thin condyle, no bone, full flexion. case: thin condyle, no bone, full flexion. *Tsai et al., SFB 2001 Image removed due to copyright considerations
ADVANTAGES OF OXINIUM Weds the best of a ceramic with the best of a metal Scratch resistant: less abrasive wear of pe More lubricatious: lower friction may result in less adhesive wear of pe, better patella articulation Much lower modulus than Co-Cr alloy(similar to Ti): lower stiffness and less stress shielding Non-allergenic
ADVANTAGES OF OXINIUM ADVANTAGES OF OXINIUM Weds the best of a ceramic Weds the best of a ceramic with the best of a metal. with the best of a metal. • Scratch resistant: less abrasive wear of PE Scratch resistant: less abrasive wear of PE • More lubricatious lubricatious: lower friction may result in : lower friction may result in less adhesive wear of PE; better patella less adhesive wear of PE; better patella articulation articulation • Much lower modulus than Co Much lower modulus than Co -Cr alloy (similar to Cr alloy (similar to Ti): lower stiffness and less stress shielding Ti): lower stiffness and less stress shielding • Non -allergenic allergenic
WEAR PROCESSES sperity Metal Adhesive wear Abrasive particle adherent plowing wear to metal PE Component Crack propagated by cyclic loading results in fatigue (delamination) wear
WEAR PROCESSES WEAR PROCESSES Adhesive Adhesive wear particle adherent particle adherent to metal to metal Abrasive Abrasive plowing wear plowing wear Crack propagated by cyclic Crack propagated by cyclic loading results in loading results in fatigue fatigue (delamination) wear (delamination) wear PE Component Metal Asperity Asperity
WEAR PROCESSES sperity Metal Abrasive wear Component Solution is a scratch-resistant metal/ceramic counterface; X-linked PE may not be the solution
WEAR PROCESSES WEAR PROCESSES Abrasive Abrasive wear PE Component Metal Asperity Asperity Solution is a scratch-resistant metal/ceramic counterface; X-linked PE may not be the solution
EFFECT OF A SINGLE SCRATCH ON PE WEAR Profound effect of a single scratch; wear due to the ridge of metal bordering an scratch 10-fold increase in PE wear when the ridge bordering the Image removed due to scratch exceeded copyright considerations 2um in height No Pe wear if the metal ridge is removed (This type of scratch is not oticeable by eye. Dowson, et al, Wear(1987)
• Profound effect of a single scratch; wear due Profound effect of a single scratch; wear due to the ridge of metal bordering an scratch to the ridge of metal bordering an scratch EFFECT OF A SINGLE SCRATCH EFFECT OF A SINGLE SCRATCH ON PE WEAR ON PE WEAR 10-fold increase in fold increase in PE wear when the PE wear when the ridge bordering the ridge bordering the scratch exceeded scratch exceeded 2µm in height m in height (This type of (This type of scratch is not scratch is not noticeable by eye.) noticeable by eye.) No PE wear if the No PE wear if the metal ridge is metal ridge is removed removed Dowson, et al., Wear (1987) ., Wear (1987) Image removed due to copyright considerations