Cementless fixation of polyethylene acetabular component in total hip arthroplasty.

A new concept of cementless fixation of a polyethylene acetabular component for total hip arthroplasty is presented. The spherical cup is fixed directly to the subchondral bone of the acetabulum by means of two pegs and screws. The polyethylene in direct contact to the bone adjusts to the deformation of the pelvis (Isoelasticity). Bone grows into the indentations of the outer surface of the implant. The elastic cup does not interfere with the physiological stress patterns of the hip joint so that a stable "biomechanical incorporation" of the implant is achieved. A follow-up of the first 250 cementless fixed polyethylene cups with an observation period of six months to four years with an average of 19 months is reported. So far no aseptic loosening of the implant has occurred.