David W. L. Hukins

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X-ray diffraction shows that the collagen fibrils of dog, pig and human meniscus tend to be oriented circumferentially in the bulk tissue and radially in the surface region. Individual fibrils are not all oriented in these directions but are distributed about the preferred orientations with a standard deviation of around 15 degrees in the bulk tissue.(More)
BACKGROUND Polyurethane (PU) foam is widely used as a model for cancellous bone. The higher density foams are used as standard biomechanical test materials, but none of the low density PU foams are universally accepted as models for osteoporotic (OP) bone. The aim of this study was to determine whether low density PU foam might be suitable for mimicking(More)
The viscoelastic properties of the nucleus pulposus were measured in compression for 35 specimens dissected from 9 sheep. Measurements on 19 specimens were made on the day of slaughter; the remaining 16 specimens were stored frozen and thawed before testing. A preload of 0.2 N was applied to each specimen and a cyclic compression of 10 microm applied at(More)
BACKGROUND Articular cartilage is a viscoelastic material, but its exact behaviour under the full range of physiological loading frequencies is unknown. The objective of this study was to measure the viscoelastic properties of bovine articular cartilage at loading frequencies of up to 92 Hz. METHODS Intact tibial plateau cartilage, attached to subchondral(More)
Seventeen specimens of lumbar discs, attached to the caudal and cranial halves of the adjacent vertebral bodies, were subjected to a maximum compressive load of 5.5 kN in six stages. The time between each stage was about 15 seconds. At each stage of compression, a radiograph of the specimen was recorded, and the bulging of the end-plate into the caudal(More)
Screw fixation can be extremely difficult to achieve in osteoporotic (OP) bone because of its low strength. This study determined how pullout strength is affected by placing different bone screws at varying angles in normal and OP bone models. Pullout tests of screws placed axially, and at angles to the pullout axis (ranging from 10° to 40°), were performed(More)
An analysis of the bulging of the annulus fibrosus as a function of the height of the intervertebral disc during compression is presented. The theory was compared with the results of experimental tests on rabbit lumbar discs. When viewed in profile the ventral bulge closely resembled an arc of a circle; at each stage of compression it appeared to extend(More)
Equations have been derived for calculating the stress distributions in a tapered reinforcing fibre in a composite material, i.e. for a fibre which does not have a uniform radius. In general, deformation of the matrix in a composite induces a radial (compressive) stress at the fibre surface and an axial (tensile) stress. The equations were solved for a(More)
The finite-element method was used to calculate the axial stress in an elastic fibre embedded in an elastic matrix to model a fibre-composite material. Axisymmetric models were created for cylindrical, ellipsoidal, paraboloidal and conical fibres embedded in a matrix and characterized by a fibre axial ratio, q. The effects of varying q, from 200 to 1000,(More)
The organization of collagen in the supraspinous, interspinous, and longitudinal ligaments, as well as the ligamenta flava, in lumbar spines from human cadavers has been investigated by polarized light microscopy, scanning electron microscopy, and x-ray diffraction. These experiments were performed on ligaments in situ, with their bony attachments(More)