[Scientific Assessment of 350 Failed Metasul-LDH® Hip Prostheses with DUROM® Acetabulum Component with Probable Conus Insufficiency, Implanted in a Single Centre During 2003 to 2008]. / Wissenschaftliche Auswertung von 350 fehlgeschlagenen Metasul-LDH®-Hüftprothesen mit DUROM®-Azetabulumkomponente bei Verdacht auf Konusinsuffizienz, implantiert in einem einzelnen Zentrum 2003 bis 2008.

Introduction: The revision rates were high for patients with Metasul-LDH® hip prosthesis (LDH = large-diameter head) with DUROM® acetabulum components implanted in a single centre between 2003 and 2008. This suggested that there was a system-related weakness in total hip replacements with large diameter heads. It was suspected that the tapered connection between head and stem was responsible for the implantation failure. This led to a scientific reappraisal of the unsuccessful hip prostheses, in order to clarify whether there was a tribological problem or a cone failure. Method: To this end, data on serum metal concentrations, types of prosthesis and stem alloys were collected and analysed for the 315 patients with 350 DUROM®-LDH-HTP. Results: There were significant differences between blood metal concentrations in patients with different types of stem. For patients with titanium stems, there were more serious affects on bone substance surrounding the affected joint, and significantly higher serum cobalt concentrations. Conclusion: It was concluded that the problem did not lie with the tribology of the sliding surfaces, but with the cone-stem connection.

[Disappearing hip--algodystrophy of the hip]. / "Disappearing hip"--Die Algodystrophie der Hüfte.

Algodystrophy of the hip--also characterized as disappearing hip, transient demineralization of the hip, neurotropic rheumatism of the hips, or osteolytic arthropathy of the hips--is a pseudoinflammatory disease entity with normal inflammatory parameters involving movement- and load-dependent pain and radiologically visible demineralization of the femoral head. The osteolysis may be so pronounced that the femoral head has become virtually invisible (disappearing hip). The wide spectrum of possibilities in differential diagnosis, including inflammatory hip diseases in particular, together with the rarity of "disappearing hip", often allow diagnosis only retrospectively if the condition has not been thought of from the outset. The usually spontaneous course without residues can be markedly shortened by calcitonin treatment, therapy with nonsteroid antirheumatic agents, or by prednisone treatment. We report 2 cases of "disappearing hip" with typical course treated at the Orthopedic Clinic of Olten Cantonal Hospital in the period 1980 to 1988.