Radiological assessment revealed a complete osseoin-tegration in all 3 zones according to DeLee and Charnley in 98%. 1 cup with a continuous radiolucent line implanted after a acetabulum fracture had to be revised after a 13 year follow-up. 10 cups migrated either in the vertical or horizontal plane 2–5 mm without any progression after 2 years postoperatively. One cup had expansile osteolyses and had therefore to be revised after 13 years. With this exception there was no evidence of osteolyses in the periacetabular pelvic bone. Brooker III and IV ectopic ossifications was seen in decentration of the head of the stem as a sign of increased polyethylene-wear. Discussion: The excellent clinical and radiological results are supported by histologic investigations of 27 autopsy-specimens which show throughout a perfect osseoin-tegration with reinforcement of the osseous anchoring in the peripheral zones of the press-fit cup. We explain the wide absence of osteolyses with the disclaiming of a metal backing (preservation of elasticity and avoiding of stress shielding) and the disclaiming of using screws.
The need for supplementary screw fixation in acetabular revisions is still widely debated. We carried out 439 acetabular revisions over an eight-year period. In 171 hips with contained or small segmental defects, the Morscher press-fit cup was used. These revisions were followed prospectively. No screws were used for additional fixation. A total of 123 hips with a mean follow-up of 7.4 years (5 to 10.5) were available for clinical and radiological review. There was no further revision of a press-fit cup for aseptic loosening. Radiological assessment revealed osteolysis in three hips. Of the original 171 hips there was cranial and medial migration of up to 6 mm at two years in 44 (26%). No further migration was seen after the second post-operative year. Acetabular revision without screws is possible with excellent medium-term results in well selected patients.