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Biomedical subjects

M Ungethüm

Publications and source records attributed to M Ungethüm.

At least 37 records · Page 2Linked to original sources
PubMed1978

[2nd Generaltion of the Munich hip-joint-simulator (author's transl)].

In addition to the improved, universal unsable, electronic-hydraulic directed hip-joint-simulator type "MUNCHEN I", a new simulator with simplified construction has been developed. This mechanical hip-joint-simulator is marked by a dual drive of movement and strain mechanism, that has been realized by a toothed belt drive. The adjustable, three-axial movement simulates level walking. According to its special, easier design the new simulator is highly adapted for comparative testing of total hip endoprostheses regarding the fields of quality improvement or standardization testing.

Biomechanical Phenomena↗
PubMed1978

[Investigations on tribology and strength of aluminium-oxide-ceramic--hip endoprostheses (author's transl)].

The nature of friction and wear of ceramic material and ceramic hip endoprostheses by different manufacturers has been investigated by means of model test equipment and gait-simulators. Thus the aptitude of ceramics to be frictional partners for artificial joints can be attested, the results give the hope of a long usability. Anyway there is the demand to the manufacturers to give a garantee for the breaking strength of the cone--plug-in-connexion and a highest productional quality of the sliding faces. The long-term testings are carried on.

Aluminum Oxide↗
PubMed1978

[Standardization of implant materials shown by "bone cement". Comparative investigations in consideration of antibiotic admixtures (author's transl)].

Test methods for acrylic based bone-cements proposed by a draft international standard are approved by investigation of different bone cements. The cements showed different qualities and different mechanical properties. Added antibiotics slow down the polymerisation, possible influences to mechanical properties are covered by handlingcaused deviations. Pressure test and impact test are leading to different strength statements.

Anti-Bacterial Agents↗
PubMed1977

[Development of a knee joint simulator (author's transl)].

This Knee Joint Simulator serves to investigate the tribological behaviour of total knee prostheses. In order to register the most important influences upon it, it is necessary to derive first of all the requirements upon the simulation of the various movements and loads from the physiological knee joint. These and some other requirements which are of a common sort, serve as the basis of the construction, the function of which is to be described in the following passage.

Biomechanical Phenomena↗
PubMed1977

[Systematy of artificial knee joints considering constructional characteristics of the natural knee joint (author's transl)].

The subject of this investigation is to spezify artifical knee joints. For this purpose the most important constructional peculiarities and functions of the natural knee joints are to be opposed to them of the artificial ones. This analysis is based on the kinematic and theory of construction. The systematy distinguishs the various artificial knee joints considering the characteristics that are thought to be substantial.

Biomechanical Phenomena↗
PubMed1977

[Standardization of implants shown by "bone-screws" (author's transl)].

The increasing use of orthopaedic implants makes international efforts of standardization with their objectives unification and benefit of the patient necessary and sufficient. In 1975 an ISO-Draft for "bone-screws" has been finished. To get experimental data there was a test series of breaking bone-screws of five producers by torsional stress. Comparable screws showed considerable differences. The control of conformity to standards gave partially distinct differences to the standard profile and different hardness values, what affects to the screws' security of twisting off.

Bone Screws↗
PubMed1977

[Muscular absorption of low frequency resonance in animal experiments (author's transl)].

For the further clarification of helicopter pilot's spinal troubles caused by vibration the muscular absorption was examined with the help of animal experiments. On a swinging-table acceleration values were measured in Pirbright cavies; at first this was done under a defence reaction of the muscles, and in second experiment under maximum muscular relaxation. In the tense animal the resonance occurring at 5 Hz was almost completely absorbed, whereas in the relaxed animal a clear resonance--curve could be developed at 5 Hz. On the other hand vibration at a higher frequency up to 15 Hz were to an increasing extent better absorbed in the relaxed animal than in animal with a muscular defence reaction. For this reason the protective function of a not fatigued musculature for the defence of especially badly tolerated resonance vibrations is being discussed.

Animals↗
PubMed1977

[Biomechanical considerations on stress and strain of the anchorage of femoral prostheses stems (author's transl)].

The nature of load and stress on implanted femoral prostheses is shown by simplified models. Bending stress is responsible for loosening and fracture of prosthesis stems. Implantation in valgus position diminishes the possibility of failure. Investigations on materials and the strength of form could clear up different influences and shall lead to allbountiful criterions and test-methods.

Biomechanical Phenomena↗
PubMed1976

[Mechanics and type of prosthesis. Biomechanical considerations on the problem of clearance of hip prostheses (author's transl)].

To an increasing extent the total replacement of a hip joint damaged by disease or trauma is increasing in importance. Yet the implantation systems in use at the present time show defects which lead to increased rates of reoperation. In particular, the reactions at the implantation-tissue limiting surface must be specially mentioned. A number of technical parameters are therefore discussed which arise as possible causes for prosthesis clearance.

Arthroplasty↗
PubMed1975

[Clinical and experimental experiences of important factors concerning the permanent anchorage of hip-joint-prostheses (author's transl)].

Amomg a lot of conditions influencing the permanent anchorage of hip-joint-prostheses the following factors are very important: form and surface conditions of the material, in addition to a valgus position of the prostheses. The importance of these parameters in changed biomechanics after arthroplastic replacement is confirmed by measurements of spherical shape, morphology of the surface and diameter of the material. Furthermore, the vectorial distribution of weight by the different varus and valgus positions were examined. The experimental results were confirmed by clinical studies on 1407 prostheses during the course of 5 years.

Alloys↗