Biomedical subjects

J Siraky

Publications and source records attributed to J Siraky.

3 recordsLinked to original sources

PubMed1988

Multichannel strain gauge telemetry for orthopaedic implants.

In vivo measurements of the loads and deformations occurring in orthopaedic implants will allow future improvements to be made. This paper describes an extremely small telemetry for long term measurements with three strain gauges and methods for an absolutely safe implant design. Developed for measuring the load at hip prostheses, the telemetry can also be used for other implants. Its size makes feasible instrumentation of devices with only slight mechanical modifications. In addition to the description of our own measuring system, the paper gives a survey on the problems of telemetrized implants, on methods for measuring spatial loads, and on the investigations of other authors. Future publications will present in vivo measurements with this telemetry, among others on hip endoprostheses.

Equipment Design↗

PubMed1984

A comparison of hip joint forces in sheep, dog and man.

The hip joint forces of sheep and dogs were measured with instrumented endoprostheses and the results were compared with reported data concerning these forces in man. In all animals load directions with 0 to 30 degrees inclinations relative to the femoral axis predominated. The transverse components mostly acted from medio-ventral directions. While the force orientations varied little during each single stance phase, they changed rapidly during the swing phase. Strong inter- and intra-individual differences of load directions were found in all animals. Irregular forces, acting upwards or transverse to the femur, were frequently observed. Maximum joint forces were up to 110% of body weight and depended more on the postoperative time than on the walking speed. Load orientations in the animals were similar to those reported for man. In this regard sheep and dogs appear equally well suited for tests of hip endoprostheses for man.

Animals↗

PubMedDate not supplied

[Reproducibility of surface measurements of the back using the opTRImetric method].

The early detection of scoliosis as well as the supervision of its progress without or with a minimal number of X-rays, is the aim of surface measurements by the opTRImetric method. The device, the method and the measured variables are described. The main aim of the work was the determination of the reproducibility of the measured variables. The variation of the measured variables caused by the stance and measurement method are given. It appears that the use of a balance for equal footloading results in a posture different from the "normal" one, and that the reproducibility of this posture seems even less than of the posture adopted when equiloading of the legs is subjectively attempted.

Adolescent↗