Search PubMed⌕ Search

Biomedical subjects

F Graichen

Publications and source records attributed to F Graichen.

40 records · Page 3Linked to original sources

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↗

[In-vitro measurement of loading using an instrumented vertebral internal fixator].

Only little is known about the loads acting on internal spinal fixation devices. The forces and moments for different external loads were now measured using instrumented implants. Measurements were performed on intact cadaver spines and after a corpectomy. Additionally the influence of the mounting accuracy on the distribution of the loads in the fixators was investigated. It could be shown that the implants are not loaded symmetrically. After a corpectomy the loads on the implants are significantly higher than for an intact spine.

Aged↗

[In vivo measurement of hip joint stress. 1. Physical therapy].

The forces acting during physiotherapy in both hip joints of one patient have been measured in vivo using a telemeterized joint prosthesis. During supported exercises the loads are up to 50% of the body weight (BW). Active movement of the leg against resistance in a lying position let the forces rise up to 250% BW. During symmetric two-legged-stance the load is typically 70% BW, while during walking peak values of about 300% BW were measured. By use of one crutch a 25% reduction of the joint force can be achieved.

Biomechanical Phenomena↗