SCYON FOSSA™ double shell acetabular cup
- reduces stresses on the poly liner
- improves lubrication – reduces friction
- reduces wear
- prevents stress shielding of bone
- enhances ingrowth by fluid convection
SCYON FOSSA™ cup reduces peak solid stressin the poly liner by a factor of two and a half [1]
Conventional (spherical) poly liner geometry high contact stresses at the pole
FOSSA™ (aspherical) poly liner geometry** annular surface contact area spreads the load
SCYON FOSSA™ cup improves lubrication and reduces coefficient of friction by a factor of two [2]
Conventional (spherical) poly liner geometry high contact stresses at the pole
FOSSA™ (aspherical) poly liner geometry** sustains fluid flow out of the fossa and maintains fluid film lubrication
Improved lubrication and reduced contact stress result in a factor three lower poly liner wear rate [1]
Conventional (spherical) poly liner geometry high contact stresses at the pole + dry friction → high wear rate
FOSSA™ (aspherical) poly liner geometry** lower contact stresses + fluid film lubrication → reduced wear rate
SCYON FOSSA™ liner is backed by a titanium double shell*** facilitating rapid bony ingrowth [3]
Conventional porous coated metal backing allows for only diffusion mass transfer and thus low bone ingrowth rate
Perforated compliant outer shell of SCYON FOSSA™ cup drives convective mass transfer out of the extant bone and accelerates ingrowth
SCYON FOSSA™ double shell cup backing is highly compliant, minimizing stress shielding [4]
Conventional porous coated metal backings are very stiff resulting in high and very localized stresses
Perforated compliant outer shell of SCYON FOSSA™ cup is highly compliant – loaded from equator, it uniformly spreads the load into bone convective mass transfer out of the extant bone and accelerates ingrowth
**, *** Patent pending
[1] S. Tepic, S. Bresina, M. Hintner, C. Kaddick, Reduced wear of UHMWPE THR liner with modified contact geometry, ORS, San Diego, 2007
[2] N.E. Bishop, F. Waldow, M.M. Morlock, Friction moments of large metal-on-metal hip joint bearings and other modern designs, Med. Eng. Physics, 30; 1057-1064, 2008
[3] S. K. Lauer, M. A. Nieves, J. Peck, R. R. Pool, G. Hosgood, T. Lazar, E. Swanson, Descriptive histomorphometric ingrowth analysis of the Zurich cementless canine total hip acetabular component, Vet Surg., 38(1):59-69, 2009
[4] T. G. Guerrero, P. M. Montavon, Zurich cementless total hip replacement: retrospective evaluation of 2nd generation implants in 60 dogs, Vet Surg., 38(1):70-80, 2009