FIXATION OF THE MODULAR TOTAL HIP FEMORAL COMPONENT IN CEMENTLESS TOTAL HIP-ARTHROPLASTY

Cementless femoral component fixation with a modular design that achie ved tight fit in the proximal and distal femur was evaluated. The base of the femoral neck made the most important contribution, but diaphys eal bony interlock also contributed significantly to immediate torsion al fixation. Fluted surface and slotted distal design produced fixatio n that was superior to fully porous-coated and cemented cylindrical st ems. Early cyclical loading improved fixation, and under moderate tors ional loads (up to 20 N-m), no measurable interface slippage occurred with the modular implant.