ABSTRACT
The loads measured at instrumented joint replacements and other orthopaedic implants allow the optimization of their stability, wear properties, fixation stability and kinematic properties prior to clinical applications. The data obtained also indicate which activities cause very high loads and should be avoided by the patients in order not to endanger the long-term success of the implant. In addition, physiotherapy after joint arthroplasty and fractures can be further improved on the basis of these data. The technical principles for such measurements are summarized and examples for the design of load measuring instrumented implants are presented. The most important results are presented based on the measurements taken at the hip and shoulder joints, internal spinal fixation devices, vertebral body replacements and knee joints. Using this data, many practical conclusions are drawn. Due to the huge amount of data obtained from the hip, most practical advise can be provided to patients with replacement or disorders involving this joint.
Subject(s)
Equipment Failure Analysis/instrumentation , Joint Prosthesis , Joints/physiopathology , Monitoring, Physiologic/instrumentation , Telemetry/instrumentation , Transducers , Weight-Bearing , Equipment Design , Equipment Failure Analysis/methods , Humans , Joints/surgery , Manometry/instrumentation , Manometry/methods , Monitoring, Physiologic/methods , Stress, Mechanical , Technology Assessment, Biomedical , Telemetry/methodsABSTRACT
Using Hjorths source derivation for more than four years 1034 routine EEG were evaluated by means of a classifiying evaluation-sheet. Ten variations of local effects were defined by materials requirements. Detection and differentiation of those local effects compared in reference, bipolar and common reference recordings and source derivation. It is shown that all information received from standard recordings is also evident in source derivation. Furthermore there are a lot of additional findings and - proved by illustrating examples - a respectable number of findings which could not be detected by standard recordings. A spatial model figures the superiority of source derivation in detection and discrimination of local effects.
