Clinical results and radiologic findings after cementless implantation of PCA stems in total hip replacement.

The results of radiologic and clinical follow-up of 81 PCA (porous coated anatomie) hip joint prostheses implanted in our clinic between 1986 and 1988 are presented. One of the prostheses had to be explanted because of aseptic loosening after 2.5 years' implantation. Contrary to the fixation concept of the prosthesis, which requires both proximal osseointegration and free axial shifting of the distal part of the prosthesis, our follow-up radiographs showed proximal lysis of 2 mm and more as well as distal hypersclerosis of 3 mm and more in the form of endosteal bone formation in 70% of cases 3 years after implantation. On the basis of our data, the question whether these bone reactions will finally lead to aseptic loosening of the implant cannot be answered yet.