RADIOGRAPHIC ASSESSMENT OF CEMENTLESS FEMORAL COMPONENTS - CORRELATION WITH INTRAOPERATIVE MECHANICAL STABILITY

The correlation between preoperative radiographic findings and intraop erative testing for stability was evaluated for 75 cementless femoral components. Fourteen of 45 porous-coated prostheses were unstable. The following radiographic signs were correlated with instability in orde r of significance: radiolucent lines at the bone-prosthesis interface covering greater than 50% of the porous interface, a distal pedestal, calcar hypertrophy, poor implant-cortical contact, and varus component alignment. Signs consistent with implant stability were good implant- cortical contact, spot welds, and calcar atrophy. Preoperative radiogr aphs have predictive value in assessing the mechanical stability of th e cementless femoral component at the time of surgery.