[Hemi-alloarthroplasty with intermediary hip joint endoprosthesis]

Intermediary (bipolar) endoprostheses have been used for the treatment of hip fractures in the past 30 years. Our cinematographic X-ray examinations have confirmed the function of the intra-prosthetic joint in vivo. Physiological load distribution in the acetabulum of "hard-top" cups was demonstrated in an experimental model by holographic interferometry. Our follow-up of 634 intermediary endoprostheses which had been implanted in a 15-years period demonstrated good clinical results. But it confirmed that "soft-top" cups should no longer be used because of the problems of polyethylene wear debris from the cup surfaces. Scintigraphic examinations in 123 cases showed the advantage of the test over X-ray examinations in early recognition of acetabular protrusion.