Factors affecting stability of press fit acetubular cups.
Press fitting cementless porous coated acetabular components without screw fixation is desirable to minimize
debris-related problems. Compression between the bone and periphery of an acetabular component
which is slightly larger than the reamed acetabulum provides implant fixation while oversizing at
the dome may adversely affect stability. In most primary total hip arthroplasties, the acetabulum can be
reamed to a hemispherical cavity and assessed using acetabular sizing trials prior to implanting the cup. Use
of an implant with a hemispherical dome and gradual transition to a wider peripheral dimension maximizes
peripheral bone strains and implant stability with less impaction force and overall deformation than a larger
oversized hemispherical cup.
Bassett Healthcare, Cooperstown, N.Y.
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