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Biomedical subjects

D Warwick

Publications and source records attributed to D Warwick.

34 records · Page 2Linked to original sources
PubMed1995

Death and thromboembolic disease after total hip replacement. A series of 1162 cases with no routine chemical prophylaxis.

We studied 1162 consecutive total hip replacements (THR) to establish the incidence of fatal pulmonary embolism (PE), clinical non-fatal PE and deep-vein thrombosis (DVT) in the six months after surgery. Chemical thromboprophylaxis had not been routinely used. We used a validated questionnaire supplemented by post-mortem records and a review of the clinical notes. Follow-up was 100%. The death rate from PE was 0.34% (95% CI 0.09 to 0.88), with one fatal PE after discharge 40 days after operation. The clinical PE rate confirmed by imaging was 1.20% (CI 0.65 to 2.02), with 0.7% of patients readmitted. The venographically-confirmed clinical DVT rate was 1.89% (CI 1.11 to 2.76), with 1.13% readmitted. The total thromboembolic morbidity was 3.4% (95% CI 2.5% to 4.7%); prophylaxis to reduce this would be justifiable if the complications of such prophylaxis did not produce an alternative morbidity. The fatal PE rate after THR without routine chemical prophylaxis was low; a very large randomised clinical trial would be required to demonstrate directly whether any prophylactic measure could reduce this. There is a large discrepancy between the high DVT rate reported in clinical trials using universal screening venography and the symptomatic DVT rate shown in this study. We found insufficient evidence to recommend continuing thromboprophylaxis after discharge from hospital.

Aged↗
PubMed1994

Measurement of femoral vein blood flow during total hip replacement. Duplex ultrasound imaging with and without the use of a foot pump.

We examined ten femoral veins with duplex ultrasound during total hip replacement to demonstrate the operative manoeuvres which cause venous obstruction and to assess prophylactic measures which may overcome it. Exposure of the acetabulum by distraction of the femur with a hook was less likely to occlude flow than retraction with bone levers. Adequate exposure of the femoral shaft by adduction, flexion and either internal or external rotation caused cessation of flow in all cases. In four cases an A-V Impulse System foot pump was activated during periods of stasis. In each case it overcame the obstruction and produced peak velocities which were twice that of the resting state. In five cases, towards the end of the procedure, debris was seen travelling proximally through the femoral vein.

Blood Flow Velocity↗
PubMed1993

Radiological measurement of radial shortening in Colles' fracture.

100 consecutive patients with Colles' fracture were assessed functionally three months after the injury, and the result correlated with initial shortening of the radius. Three methods were used to measure radial shortening; only the one that measured the distance from distal radial to distal ulnar surfaces correlated with functional outcome. It is concluded that this is the most valid method of measurement and the deficiencies of the other methods are discussed.

Colles' Fracture↗
PubMed1993

Function ten years after Colles' fracture.

There are no data in the literature concerning the outcome of Colles' fracture beyond six years. One hundred consecutive patients with displaced Colles' fractures were reviewed ten years after the injury. Function, radiographic anatomy, osteoarthrosis, and reflex sympathetic dystrophy (algodystrophy) were all objectively assessed. By the time of this review, 35 patients had died. Eighty-five percent of those surviving had a satisfactory outcome. Forty-two percent had improved functionally in ten years and 20% had deteriorated. Initial and ten-year radial shortening and early finger stiffness significantly correlated with final outcome. Dorsal angulation influenced early but not ten-year function. Sixty-two percent of those with an unsatisfactory result had objective features of reflex sympathetic dystrophy, compared with only 6% of those with a satisfactory result. Osteoarthrosis was found in 37%, but in only 4% was it associated with an unsatisfactory outcome.

Adult↗
PubMed1992

Features of algodystrophy ten years after Colles' fracture.

The long-term outcome of algodystrophy is unknown. Ten years after Colles' fracture, 26% of 55 cases showed features of the syndrome. The finding of poor finger function three months following the fracture correlated significantly with the presence of components of algodystrophy after ten years.

Aged↗
PubMed1989

Loads on the lumbar trunk during level walking.

The goal of this study was to estimate the loads internal to the lumbar trunk that arise during level walking. To do this, (a) trunk muscle activities were calibrated in terms of muscle contraction force levels in a set of isometric exertions; (b) trunk muscle myoelectric activities were measured during level walking; and then (c) the muscle contraction forces that arose during walking were calculated from these measurements and calibrations. Lumbar trunk muscle myoelectric activities were quantified in 10 healthy young males. Myoelectric activities were monitored using eight bipolar surface electrode pairs placed around the trunk at the level of the third lumbar vertebrae. The subjects first performed four static weight-resisting tasks to calibrate muscle force/activity relationships. They then traversed a 8.25 m walkway three times each at cadences of 72 and 120 steps/min. A biomechanical model incorporating 22 lumbar trunk muscles was used to predict muscle contraction forces for the calibration tasks. Predicted forces were linearly correlated with the measured myoelectric activities for these tasks. The regression equations were then interpolated to estimate the muscle contraction forces from the myoelectric data during gait. Peak contraction forces for the iliocostalis muscles were calculated to be approximately 55 N per side, corresponding to total erector spinae peak contractions on the order of 140 N per side. For the other six muscles that were monitored, contraction forces were less than 15 N per side. This suggests that peak net reaction moments and peak spine compressions on the lumbar trunk during these walking tasks were on the order of 15 Nm and 1.2 times body weight, respectively.

Abdominal Muscles↗
PubMed1987

Lumbar trunk muscle use in standing isometric heavy exertions.

A study was conducted to see whether a biomechanical model previously validated for predicting the lumbar spine internal loads imposed by the performance of easy and moderately strenuous physical tasks was also adequate for predicting loads imposed by heavy exertions. Lumbar trunk muscle myoelectric activities were measured in 10 healthy young adult men performing a variety of less strenuous and more strenuous tasks while standing upright, and these were compared to the lumbar muscle contraction magnitudes predicted by the model. For the less strenuous tasks, measured activities and predicted forces showed strong linear correlations, confirming the validity of the model at those load levels. Model predictions for the more strenuous tasks were often found to be inadequate. Contrary to model-incorporated assumptions, substantial antagonistic muscle contractions sometimes occurred, intraabdominal pressurization may sometimes have contributed substantially to the maintenance of structural equilibrium, and the ligamentous tissues of the trunk seemed sometimes to develop substantial passive resistances to bending and twisting moments.

Adult↗
PubMed1986

Direct contact B-scan ultrasound in the diagnosis of solid breast masses.

Our experience of breast ultrasound in the differentiation of benign and solid malignant breast masses indicates a specificity of 93% for carcinoma; 7% of cancers were regarded as benign. Eight of 89 proven fibroadenomas were considered possibly malignant. Typical, and overlapping, features are described, and the world literature is discussed. Whereas most previous workers have used a water-path technique, we employ direct contact B-scanning, which is quick, simple, and apparently at least as successful. The small group of solid masses where there is overlap between fibroadenoma and carcinoma needs further study; this might be helped by histological correlation with the ultrasound appearances of malignancy, the causes of which are still debated. The exclusion of a focal solid mass in a patient with a breast lump can reduce the biopsy rate.

Adenofibroma↗
PubMed1983

Use of lumbar trunk muscles in isometric performance of mechanically complex standing tasks.

Ten subjects performed 25 tasks isometrically while standing. Those tasks imposed substantial extension, lateral bending, and twisting moments on the lumbar spine. Mechanically complex trunk muscle actions were called for to resist those moments. Biomechanical model analyses were used to predict the trunk muscle contraction forces needed to perform those tasks, and surface myoelectric activities were measured to validate those predictions. Predictions and measurements were linearly well correlated.

Adult↗
PubMedDate not supplied

Trunk strengths in attempted flexion, extension, and lateral bending in healthy subjects and patients with low-back disorders.

Trunk strengths were measured in 27 health males and 30 health females, and in 25 male and 15 female patients with low-back pain and/or sciatica. Maximum voluntary isometric strengths were measured during attempted flexion, extension, and lateral bending from an upright standing position. Both male and female patients had approximately 60% of the absolute trunk strengths of the corresponding healthy subjects. Intra-individual trunk strength ratios were used to interpret the results. Use of these ratios tends to avoid interpretational problems created by the general weakness of the patients and any lack of motivation of either patients or healthy subjects. The ratios showed that the patients had attempted extension strengths that were significantly less than their strengths in the other types of movements tested. The strength ratios for attempted extension were particularly low for patients with sciatica.

Adult↗