Search PubMed⌕ Search

Biomedical subjects

R J Benink

Publications and source records attributed to R J Benink.

4 recordsLinked to original sources
PubMed2002

Measuring functional abilities of patients with knee problems: rationale and construction of the DynaPort knee test.

We present the rationale and design of the DynaPort knee test. The test aims at measuring knee patients' functional abilities in an unobtrusive, user-friendly way. Test persons wear several belts around their trunk and legs. The belts contain accelerometers, the signals of which are stored in a recorder, embedded in one of the belts. The knee test consists of a set of 29 tasks related to activities of daily life ("test items"). Accelerometer signals are analyzed in terms of 30 "movement features" (accelerations, angles, durations, frequencies, and some dimensionless numbers). In data analysis, the beginning and end of each test item is marked by hand; otherwise, analysis is automatic. We compared 140 knee patients with 32 healthy controls and found 541 of the 29 x 30=870 test item x movement feature combinations differed significantly between the two groups. From these 541 combinations the DynaPort knee score is calculated by the weighted averages of movement features per item, then weighted averages of items per cluster (locomotion, rising and descending, transfers, lifting and moving objects), and finally the average of the clusters. In an initial study the test-retest reliability of the knee test proved high, and the test turned out to be sufficiently responsive (0.7 patients' standard deviations improvement after 24 months). However, it remains difficult to interpret the scores in more meaningful terms than merely "better" or "worse." Extensive reliability studies in the future will further assess the validity of the test and provide more insight into the meaning of the scores. The DynaPort knee test may thus become an important instrument for evaluating patients'functional abilities in knee-related clinical practice and research.

Activities of Daily Living↗
PubMed1985

The constraint-mechanism of the human tarsus. A roentgenological experimental study.

The main purpose of this investigation was to extend the work of Huson, Ambagtsheer and Van Langelaan to living subjects. It may thus be regarded as the logical continuation of Van Langelaan's study. The investigation consists of three main parts: In part 1 (Chapter 2), stepwise supination of the tarsus of fixed osteoligamentous preparations (the mode of supination studied by Van Langelaan) was compared with continuous supination. We found that stepwise supination of lower leg foot-preparations differs little from the continuous supination. The speed at which the continuous movement is carried out, and the amount of vertical loading, have only very slight effects. We could discern clearly that the visco-elastic properties of the tissues caused a difference in the paths of the supinating and pronating movements, the hysteresis effect. During this investigation we discovered by coincidence that the input moment to be applied to the tibia to supinate the tarsus by rotation varied greatly from one individual to another. The same was true for the vertical tibial translation during supination. This finding that differently shaped feet also differ in biomechanical behaviour prompted an extra line of investigation with which we attempted to quantify this biomechanical behaviour by measuring moments and recording vertical tibial translations, combining the two and relating them to a new roentgenological classification of the tarsus. The traditional specification criteria were found to be unsuitable. A strong correlation was found to exist between moment (M) and vertical tibial translation (S). Another strong correlation was observed between M and S and the tarsal index it, calculated with the equation (Formula: see text) The index is determined entirely by the relative positions of the talus and calcaneus. Part 2 (Chapter 3) comprises a study of fresh amputation material, as a step in the direction of live material. Two amputated lower legs were analyzed kinematically, according to Van Langelaan and Spoor's photogrammetric method; dynamically, by measuring moments (M) and recording vertical tibial translations (S); and finally by comparing the stepwise and continuous supination and pronation of one specimen (female 29). Each method was applied both to the completely intact specimen and to the dissected osteo-ligamentous preparations. As kinematic parameters we used the helical axes. We calculated both the relative axes (of the movements of one tarsal bone in relation to another) and the absolute discrete axes (of the tarsal bones in relation to the fixed reference system in the test setup) of supination from 0 degree -30 degrees and return.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1978

A localizing device for x-ray sources.

The author describes a localizing device which permits accurate placement of x-ray sources in relation to both the patient and the cassette. Radiographs can be reproduced exactly using this device.

Humans↗