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R Züllig

Publications and source records attributed to R Züllig.

8 recordsLinked to original sources
PubMed1983

Surface replacement hip arthroplasty with the Freeman double cup.

The authors report their clinical experience with 43 hip arthroplasties using Freeman's double femoral cup. The patients were followed up from 3 to 6 years after operation. At that time, only 44% were totally free from pain, while migration of the femoral cup, which was severe and progressive, was observed radiographically in almost half the cases. In 3 cases it was possible to study histologically the stump of the neck of the femur and the zone of contact between femoral bone and cement. Biomechanical studies were also performed with photo-elastic models, using the technique of finite elements. These studies indicated overloading on contact between the edge of the femoral cup and the cortical bone (especially medially), but without any load over the whole of the spongy bone. Consequently there was bone resorption in the overload zone and osteoporosis in the spongy bone. The femoral cup rapidly became unstable, and this produced progressive migration, thus constituting a vicious circle.

Biomechanical Phenomena↗
PubMedDate not supplied

[Freeman's double-cup total hip endoprosthesis. Clinical results and biomechanical studies].

From July 1976 up to the end of 1979 forty-three Double Cup hip replacements of the Freeman type were implanted in thirty-seven patients at the Department of Orthopaedic Surgery, Balgrist, of the University of Zurich. Now, four to seven years after implantation, 15% of early complications have developed and only 25% of all the hips are free of pain. Radiographically, every second femoral cup shows migration of about 2 mm. pro year at an average. Clinical and radiographical investigations, as well as biomechanical experiments and calculations show the possible reasons for the unsatisfactory results. Subsequently, we are now very cautious when considering the indications for the implantation of Double Cups.

Adult↗