Biomedical subjects

J Hoschek

Publications and source records attributed to J Hoschek.

4 recordsLinked to original sources

PubMed1990

Three-dimensional determination of an oblique osteotomy in the hip by mathematical optimization fulfilling some anatomical demands.

The present paper describes a nonlinear optimization process to estimate the single cutting plane of an oblique osteotomy in the hip. This kind of osteotomy was introduced and practised by Charit (Research report 81, University of Witwaters brand, Johannesburg, 1981). We calculate the cutting plane in such a way that the postoperative coverage of the resulting two parts of the femur are as great as possible whereby some anatomical constraint conditions are fulfilled. Additionally a simplified preoperative planning is described by using a sphere lying on the femoral head and determined by a least-squares method.

Biomechanical Phenomena↗

PubMed1984

Mathematical kinematics in engineering of endoprostheses. Evaluation of the results of gait analysis.

Certain optical methods (photogrammetry) achieve great precision in analysis of body motion. However, this study clearly shows that the tracing of body surface movement is unsuitable for analysis of actual joint motion, at least in the knee joint, because of the soft tissue shifting which occurs. It is also shown that comparatively simple mathematical-kinematic techniques can be used to check the degree of error of methods of measurement in orthopedics. It is to be assumed that no currently available knee joint prostheses function in a kinematically perfect manner. If the movement of knee joint prostheses is to be optimized and implantation errors affecting kinematics avoided, it seems indispensable, at the current level of technology, to employ X-ray stereophotogrammetry to describe natural knee joint motion.

Biomechanical Phenomena↗

PubMed1979

[The motility of hip joint endoprostheses (author's transl)].

The motility of a healthy hip joint normally seems to be better than the motility of an endoprosthesis. The movement of all models of endoprostheses must fulfill minimum requirements as well in total motility as in each way. The arithmetical investigation of the motility of commercial total endoprostheses shows good locomotion for most cases. Decisive is the relation between prosthesis head- and prosthesis neck diameter. Insufficient motility of endoprosthetic models results if especial--redundant--constructive details of the socket are selected. It seems to be more problematical to produce double cup endoprostheses which reveal sufficient function. Normally the motility of double cup prostheses must be essentially less than that of total endoprostheses or of a healthy hip joint. A special implant technique and various constructive assumptions are necessary to reach a sufficient functional result.

Biophysical Phenomena↗

PubMedDate not supplied

[Mathematical kinematic methods in joint prosthetics].

By the use of mathematical and cinematical methods a new understanding for the construction as well as for the implantation-techniques for endoprosthesis can be developed. With these methods the size of the natural motion and the process of the natural motion can be studied. So we get better informations about the natural motion and we can deduce criterions for the construction of endoprosthesis, for we can compare the motion of a model with the natural way of motion. So we can estimate preoperative the efficiency and the maximal load of the prosthesis as a result of incorrect motions. Such incorrect motions can be caused or can be avoid by the construction of the endoprosthesis as well as the implantation techniques.

Biomechanical Phenomena↗