Cementless acetabular reconstruction with a hemispheric acetabular shell in primary total hip arthroplasty has shown reproducible results. Ingrowth of bone into a porous coating of beads, a titanium fiber mesh, or a hydroxylapatite-containing bioactive coating has been histologically documented. Early failures of ingrowth of an acetabular component have been reported using a threaded acetabular design. A series showing high early (<1 year) failure of ingrowth into a modern acetabular component has never before been reported. We report a series showing a 33% early loosening rate of the Sulzer Interop TM acetabular component (Sulzermedica, acquired by Zimmer, Warsaw, IN).