[5- to 10-year results of an acetabulum with ceramic pegs for cement-free bone implantation. Material and analysis of design].

The authors report on the follow-up results of a hemispherical acetabular cup with small pegs, which is designed for cementless implantation in human beings. At an average time of 89 months after implantation, these results reveal a high percentage of 60% loosenings and seam formations of more than 2 mm which could constitute the basis for subsequent loosening. An analysis of these failures attributes the cause to material-engineering as well as design problems associated with the bone pathology. A ceramic cup of this shape is apparently unsuitable for osteointegration. It would appear that the design favours tilting movements and, due to its high E-module, it is unable to compensate for the relative movements of the pelvis.