The behaviour of the lumbar intervertebral disc under repetitive forces.
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Adolescent↗
Biomedical subjects
W C Hutton
Publications and source records attributed to W C Hutton.
The assessment of adolescent hallux valgus before and after first metatarsal osteotomy--clinical and walkway studies.
A comprehensive method of evaluating the feet of patients with adolescent hallux valgus both before and after surgical correction is described. Serial clinical, photographic and radiological studies were made and a dynamic assessment of gait was carried out using a load-sensitive walkway. Observations were made on 36 feet in which hallux valgus was treated by a modification of the Wilson oblique metatarsal osteotomy, with removal of a wedge of bone and screw fixation. In the first six months after operation, there was a lateral shift of the weight-bearing pattern in the forefoot and less weight was taken on the toes, but there was a tendency to return to the pre-operative distribution of weight during the next four years. Persistence of the lateral shift of weight-bearing appeared to result from elevation of the first metatarsal head secondary to shortening of the first metatarsal during the osteotomy. This can be avoided by deliberate depression of the first metatarsal head at the time of operation and fixation of the fragments in the required position with a screw.
Adolescent↗
The mechanical properties of bone in osteoporosis.
Specimens of femoral cortical bone from normal subjects and from patients with osteoporosis were mechanically tested in tension to destruction. The osteoporotic bone showed less strength and less stiffness than the normal bone; these reductions are related to the increased cavity area in osteoporosis. Further, the osteoporotic bone is not able to absorb as much energy before fracture as the normal bone; but this difference is not related to changes in cavity area.
Aged↗
The mechanics of normal and hallux valgus feet--a quantitative study.
Accurate measurements of the vertical load under areas of the foot were made with a computerized instrumentation system. In a study of 148 normal feet, the normal force distribution and its variation with age was quantified. This showed the hallux to be important in sharing the load on the first ray. comparative studies of feet with hallux valgus before and after Keller's operation showed the changes that accompany reduced hallux loading. A model of the foot was used to calculate the force across the metatarsophalangeal joint and the forces and moments acting on the metatarsals.
Adolescent↗
The tensile strength of the capsular ligaments of the apophyseal joints.
The capsular ligaments of the apophyseal joints are arranged to provide maximum resistance to flexion. They can support about twice body weight in the young although their strength decreases with age.
Adult↗
A microprocessor controlled system for evaluating treatments for disabilities affecting the lower limbs.
A system, now fully operational, for measuring and recording the temporal/distance factors of normal and pathological human gait has been described. The advantages of the system include the following: 1. it is easy to operate. 2. the results are presented in a clinically digestible form. 3. no constraints are placed on the patient. 4. it is portable. 5. results are produced immediately. These factors combine to produce a system that may assist in the evaluation of many treatment methods currently employed for locomotor disorders.
Biomedical Engineering↗
Foot function in juvenile chronic arthritis.
Measurement of the force distribution under the foot has been used to assess the effect of juvenile chronic arthritis on foot function. The results obtained from the feet of eight patients were compared with the feet of 11 normal children. The peak forces and contact times were measured for functional areas of the foot. When considered as a group, the patients had significantly reduced loading under all the toes and the two medial metatarsal heads, and increased contact time for the heel.
Adolescent↗
A comparison of different treatment regimes on the visual appearance and mechanical properties of mouse skin.
Four different regimes of radiotherapy employed in the treatment of basal cell epitheliomas were compared in order to assess their effect on the visual appearance and mechanical properties of skin. Three groups of mice received exposures identical to those given in the radiotherapy treatments; three months after completion of the radiation the visual and mechanical properties of the skin and its appendages were examined. The skin scarring, coat condition, greying of hair, skin, thickness, load at rupture, extension at rupture, mechanical stress at rupture and stiffness were used as cirteria for comparing the four treatments. The treatment regime which caused the least damage to normal skin was identified.
Animals↗
The effect of posture on the role of the apophysial joints in resisting intervertebral compressive forces.
Cadaveric lumbar intervertebral joints were loaded to simulate the erect standing posture (lordosis), and the erect sitting posture (slightly flexed). The results show that, after the intervertebral disc has been reduced in height by a period of sustained loading, the apophysial joints resist about 16 per cent of the intervertebral compressive forces in the erect standing posture, whereas in the erect sitting posture they resist none. The implications of this in relationship to degenerative changes and to low backache are discussed.
Adult↗
The incongruous hip joint. A casting study.
A casting method for measuring the intra-articular space in the loaded hip is described. The results of tests on 22 hips from 22 cadavers show that the joint space is variable both in location and size and can disappear under light loads. It seems likely that the size and shape of the space influence how much access synovial fluid has for lubrication and nutrition.
Adult↗
Mechanics of the hallux valgus foot and the effect of Keller's operation.
Using a system for measuring the load distribution under the foot, patients with hallux valgus were compared, before and after undergoing Keller's operation, with a group of normal subjects. Preoperatively the patients showed reduced loading under all their toes and increased loading under their lateral metatarsal heads; the decrease under the hallux was found to correlate with an increase in hallux valgus angle. Postoperatively there was a further decrease in loading under the hallux and an increase under the first metatarsal head.
Adolescent↗
A study of the distribution of load under the normal foot during walking.
A computerised instrumentation system which measures the distribution of vertical load under the foot has been used to measure and record the loading under 148 normal feet during walking. The correlations and variations with load, contact time, sex, age and angle of the toe out are discussed.
Adolescent↗
An apparatus for measuring the recoil characteristics of human skin in vivo.
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Biomedical Engineering↗
The mechanical properties of skin in vivo--a portable hand-held extensometer.
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Atrophy↗
Changes in load bearing in the rheumatoid foot.
A study of peak force exerted under areas of the foot was made in 27 patients with rheumatoid disease and in 30 normal persons. Patients were found to exert considerably less force under their toes and under the first metatarsal head and more force under the 3 outer metatarsal heads. It was possible to correlate these changes with increasing clinical and radiological severity.
Adult↗
The compressive strength of lumbar vertebrae.
Values for the compressive breaking load of lumbar vertebrae at physiological strain rates show enormous scatter across the population, ranging from 0.8 kN to nearly 16 kN. Increase in strength was found at faster strain rates, but differences in compressive strength between upper and lower lumbar vertebrae were not significant. Hydraulic strengthening does not appear to contribute to the compressive strength at the strain rates studied.
Adolescent↗
Forces acting on the metatarsals during normal walking.
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Gait↗
Sphingomyelin multiple phase behavior as revealed by multinuclear magnetic resonance spectroscopy.
31P and 13C nuclear magnetic resonance (NMR) spectra are employed to study the phase behavior of bovine brain sphingomyelin as a function of temperature. The 31P NMR data suggest that, while at low temperatures sphingomyelin can form a lamellar phase, at physiological temperatures and higher the lamellar phase is unstable, and a new phase, best described as a hexagonal phase, is formed. Egg phosphatidylcholine is suggested to play an important role in stabilizing bilayers in natural membranes. Cholesterol also exhibits a sphingomyelin bilayer-stabilizing ability. The 13C NMR spectra suggest a gelling of the hydrocarbon chains of sphingomyelin at low temperature. Thus, bovine brain sphingomyelin undergoes both a gel to liquid-crystalline phase transition and a lamellar to nonlamellar transition.
Animals↗