The conically clamping inlay of solid metal for the Hofer-Imhof threaded socket makes possible the use of a metal-metal-bearing by completely dispensing with polyethylen but keeping the four-elements-construction of THR. In order to perceive long-term problems and complications patients of our hospital who took part in a closed multi-center-study which was established prospectively were checked again.
Clinical and X-ray examination of 27 patients after 19 months on an average (12-23 months).
Harris-score increased from 38 points before the operation to 89 points three months after the operation and 91 points in the present check-up. Three months after the operation 22 patients were free of pain, at present only 12. X-Rays did not show any signs of loosening within the prostheses. But increasing ectopic ossifications of Brooker were found: ten times Class I, once Class II and six times Class III.
Using equal form of after treatment the increasing break out of pain as well as the growing symptom of ectopic ossifications in the hip area after the implantation of the Hofer-Imhof threaded socket with solid metal inlay is presumably caused by the use of the metal-metal-bearing as well as by the direct lining of the Co-Cr-inlay in the titan-socket and by possible changes in corrosion.