Further experimental and clinical experience with aluminum oxide endoprostheses.

This paper describes the design principles of a new endoprosthesis made of dense aluminum oxide (A12O3) and implanted without bone cement. Mechanical tests and animal experiments have proved the sufficient mechanical strength of the bone-prosthesis connection as well as the biocompatibility of the material. So far, 12 tumor patients selected according to strict indication criteria have been operated on.

[Treatment and prognosis of osteosarcoma in childhood (author's transl)].

126 osteosarcoma under the age of 15 years are followed up in an interclinical study. There is a steady increase of tumor incidence towards the 15th year with a slight male preponderance. The main sites of the tumor are the distal femur followed by the proximal tibia and humerus.

The immune-status in patients with bone and soft-tissue sarcomas.

The immunologic status of 50 sarcoma patients was established. It was possible to apply the DNCB test and the recall antigen test in most cases during the course of the illness. The PHA stimulation of the lymphocytes and their cytotoxicity on homologous sarcoma cell lines were also correlated with the course of the illness.

Resection of malignant bone tumors.

Amputation is an unsatisfactory and depressing measure for the patient as well as for the surgeon. As long as operative removal of tumors in the extermities is indicated, the search for alternative solutions should be the most urgent task for every doctor involved in surgery. Resection would be the most equitable measure as far as demands for radicality and the best possible restoration of function are concerned.

[Atypical amputations of bone tumors of the lower extremity (author's transl)].

The most predominant problem concerning malignant tumors in the lower extremities is the radical removal of the tumor, for this almost always involves amputation. Referring to the eventual outfitting of a prosthesis one must keep functionality in mind from the start. This includes all the planing for the preservation of a stump that can be fitted with a prosthesis.

Osteosarcoma in children. A study of 125 cases.

A study is presented of the aetiology and results of treatment in a group of 125 proven osteosarcomas present in children under fifteen years of age. These cases have been collected from the records of one English and six European treatment centres. There is a slight male preponderance, but the striking aetiological feature is the very high proportion of tumours of the long bones of the limbs (96 per cent).

Experiences with Al2O3 implantations in humans to bridge resection defects.

Various implants have been developed for the upper and lower extremities and the spine. In order to establish whether endoprostheses made of Al2O3 will show the same good biocompatibility in humans as it has in experiments with animals, endoprostheses implantations were performed in 4 patients: 2 upper arms, 1 radius, 1 vertebra body. The implants were exposed to various loads.

[Model for describing tremor (authors transl)].

Acceleration measurements of lower arm, hand and finger tremor principally contain several reproducible peaks in thier power spectral density function. The transfer function of the system was determined by application of a sinusiodal force with an amplitude of less than 1 p.c.

Resection therapy of malignant tumours of the shoulder girdle.

Based on 30 resections in the shoulder region, operation techniques and results are precisely described with a view to curing and functioning. In the case of radical resections the rate of recurrences and cures in patients are the same as the rate of ablations. As the function of the hand is not impaired, this is a considerable advantage over amputations, although the cosmetic result of a resection may appear insufficient.