bluuebunny/crossref_metadata_2025_split huggingface dataset:
A New Approach to Elbow Arthroplasty
Authors: Souter W A 
Published: February 2007

The development of a two component endoprosthesis, the articular surfaces of which are modelled very closely on those of the normal trochlear joint, is described. Fixation is achieved through the use of methyl methacrylate cement around a keel and stem on the ulnar side and around a supracondylar metal stirrup with projecting flanges in the capitellum and medial epicondyle in the humerus. In vitro studies suggest that this fixation should be adequate to resist the forces normally transmitted across the elbow, these forces ranging according to the activity from half to three times body weight. Early clinical results have proved very satisfactory with regard to relief of pain and recovery of flexion, pronation, supination, power and function as a whole. The recovery of lost extension has proved more elusive. A much longer follow-up of two to five years will be required in order to ascertain whether the problem of loosening has been solved.
In Vivo Hip Joint Forces Recorded on a Strain Gauged ‘English’ Prosthesis Using an Implanted Transmitter
Authors: Kilvington M , Goodman R M F 
Published: February 2007

This paper describes the results obtained from implanting a strain gauged version of an ‘English’ hip joint replacement together with a totally implantable FM radio transmitter. The implant is based upon a new concept in the design of femoral hip components having a diminished head offset to reduce head load and improved stem shape permitting alignment of the neck along the theoretical axis of peak load transmitted during the gait cycle. The implant was inserted using the ‘English’ trochanteric approach (English, 1975) which further reduces the load on a prosthetic hip joint with the use of a spacer out from the redundant femoral head to rearrange the trochanteric muscle lever arms. The resulting axial load is detected by four strain gauges mounted on a ‘piston in cylinder’ arrangement contained within the thickened neck of the prosthesis. The single channel FM transmitter relays the gauge output to a signal processing unit to give a direct output of activity for recording on a UV recorder. Recordings were taken during implantation, recovery, walking (at three days) physiotherapy, stair climbing and walking over a period of forty days.
Spinal and Pelvic Movement during Walking—A New Method of Study
Authors: Thurston A J , Whittle M W , Stokes I A F 
Published: February 2007

A non-invasive method of measuring pelvic and lumbar spinal movement during walking has been developed. Targets attached to the subject reflect light from stroboscopic lamps mounted near to each of three television cameras which are interfaced to a computer. The targets' locations are identified by the interface and stored as coordinate pairs. From the two-dimensional data from two cameras, three-dimensional data are derived and the relative movements of the lumbar spine and pelvis can be calculated. The ranges of spinal and pelvic movements in a group of twenty-two normal males have been measured. The mean values of spinal motion were 5.1° in the sagittal plane, 9.3° in the coronal plane and 8.3° axial rotation. The corresponding pelvic movements were 4.0° in the sagittal plane, 7.7° in the coronal plane and 11.2° axial rotation. The system is useful to document abnormalities and to record the effects of treatment.
The History and Development of Artificial Limbs
Authors: Orr J F , James W V , Bahrani A S 
Published: February 2007

The loss of a limb is a tragic event and artificial limbs are used to substitute for this loss. Early artificial limbs were crude, consisting of peg legs and hook hands. However, with the developments in surgery and technology better limbs became available. In the sixteenth century, surgeons who carried out the amputations recruited the help of craftsmen to provide their patients with artificial limbs which were functionally useful and resembled the shape of normal limbs. Significant advances in the development of limb fitting services have been prompted by the two World Wars. Rapid progress has been made since the 1940s. This is due to the collaboration of surgeons, engineers and prosthetists to employ new developments in technology and materials to the rehabilitation of amputees.
In Vivo Measurement of the Mechanical Properties of Bone Tissue. Preliminary Results
Authors: Burny F , Saric O , Bourgois R , Donkerwolcke M , Andrianne Y 
Published: February 2007

The paper is a preliminary report on the possibility of measuring the mechanical characteristics of the bone at the time of the anchorage of the osteosynthesis. The measurement of the maximum torque of a screw could be representative for the strength of the material.
Cancellous Bone Strength at the Proximal Human Tibia
Authors: Hvid Ivan , Jensen Jørn 
Published: February 2007

Machined specimens from ten cadaver proximal tibiae were tested in compression to study the variation of mechanical strength with the distance from the joint surface. There was a statistically significant reduction of stiffness and strength with increasing distance from the joint beneath the lateral condyle and the intercondylar area; at the medial condyle no such reduction could be demonstrated. Linear regression analysis showed that the tangent modulus may be used to predict yield strength ( r = 0.92) and ultimate strength ( r = 0.91) when destruction of the specimen is undesirable. One important limitation of the technique employed is that the length of test specimens determines the resolution that can be obtained.
Liquid Repellency and Surgical Fabric Barrier Properties
Authors: Olderman G M 
Published: February 2007

Those who are responsible for controlling the surgical environment require a technically sound, practical, valid, and consistent means of evaluating the barrier properties of surgical drapes and apparel. While many laboratories have, by necessity, agreed upon a limited number of test procedures to evaluate the liquid penetration resistance or repellency of a barrier material, there is no uniform code or guideline that defines the preferred method or methods of evaluation. Assuming wet bacterial transmission through a barrier material is related to the liquid penetration resistance of that material, the following paper attempts to outline the physicochemical basis of repellency in terms of a word equation, define the terminology and relevance to surgical barriers, and suggest the optimum choices of tests from among those in common usage including the group that had been under consideration by the Association for the Advancement of Medical Instrumentation (AAMI) Aseptic Barrier Materials Committee. Because the liquid penetration resistance of a barrier material is a function of both permeability and surface wettability, comprehensive evaluation must include tests for both properties. No single test has been shown to do this reproducibly. Two tests, used by a number of industrial labs, are recommended because, while each test reflects predominantly the degree of either porosity or wetting, together they have been shown to yield information on both properties reliably with results that can be reproduced. These two tests, the fixed liquid pressure test and the dynamic impact test, are simple, non-destructive, and require little special equipment, so they can be performed relatively rapidly on both linens and single-use non-wovens.
A Study of the Wear Characteristics of Ultra-High Molecular Weight Polyethylene Sliding against Glass
Authors: Randall J E , Dowson D 
Published: February 2007

Investigations of the wear of ultra high molecular weight polyethylene in unidirectional sliding against a range of glass counterfaces of various initial surface roughnesses are described. The tests were carried out either with the wear specimens under dry conditions of contact or lubricated by distilled water. Comparative tests under rarified atmosphere were also carried out. A single sliding speed of 0.24 m/s and two constant loads of 20 N and 80 N per test pin were used. The initial wear factors measured were often low, but the onset of a second, more severe, wear regime commonly occurred at an early stage in the testing. This phenomenon produced overall wear factors which were higher than those previously reported for this polymer sliding against both ceramic and stainless steel counterfaces of similar roughnesses after the same distances of sliding under equivalent conditions of testing.
The Bond Strength and Ageing of Plasma-Sprayed Coatings of Alumina on Metal Substrates
Authors: Randall J E , Dowson D 
Published: February 2007

Changes in the bond strength of alumina coatings after soaking in deionised water have been studied in conjunction with investigations of the wear characteristics of ultra-high molecular weight polyethylene against ceramics coated onto metal substrates. The results reported in this paper concern plasma sprayed alumina coatings, applied both directly and using an intermediate bonding layer, onto medical grade stainless steel or titanium alloy. The bond strength was measured in tension both before immersion and at various intervals over a period of up to eighteen months (13 000 hours) soaking in water. After about four months a significant deterioration in bond strength was noted. This deterioration continued for the duration of the investigation and the reductions in the bond strengths observed were often greater than 75 per cent of the original values. A white powdery deposit was found in the containers in which the ageing was carried out and a similar deposit was also seen on some of the fracture surfaces. Analysis identified Al(OH)3 and an amorphous phase of alumina. A complex diffusion mechanism appeared to have taken place which resulted in a deterioration in the properties of the ceramic coatings.
Cancellous Bone Strength Measurements with the Osteopenetrometer
Authors: Hvid Ivan , Andersen Kurt , Olesen Svend 
Published: February 2007

An instrument designed to measure cancellous bone strength at the tibial and femoral condyles during total knee replacement is described and evaluated with respect to the relationship of measurements to conventional compression tests on machined specimens in a material testing machine. The instrument, referred to as an osteopenetrometer, indirectly measures the force and depth of penetration of a needle that is advanced into the cancellous bone at constant speed. A small computer controls the measuring procedure and corrects the force readings for resistance in the hydraulic system. The relationship between osteopenetrometer measurements and compression tests is best described by a power law, with correlation coefficients of approximately 0.90 when ultimate stress data were compared. A 2.5 mm pointed needle with the shaft milled to 2.3 mm to avoid friction along the needle shaft is favoured for clinical measurements since readings from different depths beneath the resection surface may then be directly compared. The error of measurement was assessed by comparison of observed and smoothed data from measurements across tibial and femoral condylar resection surfaces. Ninety-nine per cent tolerance limits of ± 3.0 MPa (compared to a range of 0–40 MPa in units peculiar to the osteopenetrometer) were found.
Some Time Dependent Properties of the Intervertebral Joint when under Compression
Authors: Smeathers J E 
Published: February 2007

The experimental technique reported here was developed to provide data for mathematical models simulating the mechanical properties of the human lumbar spine. Dynamic compression tests on intervertebral joints from the lumbar region of sheep (body mass 50–70 kg) were used to assess the technique as human cadaveric material was not readily available. The loading pattern on the human spine during walking was simulated by exposing each joint to dynamic compression loads of 750 ± 250 N at a frequency of 1 Hz. The joints were tested at body temperature in Tyrode's solution. In order to detect the dominant viscoelastic properties of each joint the energy dissipation, spring stiffness, and creep response were monitored for twenty-eight hours. The results of these long term axial compression tests on lumbar intervertebral joints from sheep show that the joint rapidly loses its capacity to dissipate strain energy. After quarter of an hour the energy dissipation (hysteresis) of the joint has dropped from 37 per cent to less than 10 per cent. The spring stiffness of the joint under these compressive loads starts at 6 MN m–1 increasing to 12 MN m–1 by the end of the test. The characteristic time for the creep response (retardation time) occurs after two and a quarter hours.
A Microcomputer Controlled Hand Assessment System Used for Clinical Measurement
Authors: Jones A R , Unsworth A , Haslock I 
Published: February 2007

To improve the objectivity of clinical assessment of hand function, a microcomputer controlled system of force transducers has been developed and used to study twenty normal subjects and thirty-eight patients suffering from rheumatoid arthritis. The parameters measured were grip and individual finger forces, pan and kettle handle grip and lift force, key twist torque, lateral pinch force, and individual finger pulp pinch forces. ‘Power’ grip forces were found to be remarkably similar in the left and right hands as indeed was the contribution made by each finger to the total force. Pan grip and lift forces were also similar in left and right hands, but the grip force was far greater than the lift force in both normals and patients. Kettle grip forces were much less than the lift force in normal subjects, while patients gripped the kettle with almost as much force as they used to lift it. Patients were weaker than normals exerting roughly one third of the forces of normals in all modes of measurement. There were different styles of lifting demonstrated by the patient group.
A Clinical Review of the Hyperlaxity of Joints with Particular Reference to Osteoarthrosis
Authors: Bird H A 
Published: February 2007

The range of observed movement at a given joint varies with a gaussian distribution throughout the population. Individuals whose joints display an unusually high degree of laxity are susceptible to a variety of rheumatic and orthopaedic symptoms. The impression that such individuals develop premature osteoarthrosis is a strong one, but hard to prove. In addition, certain individuals with inherited abnormalities of connective tissue are undoubtedly at risk of accelerated osteoarthrosis. The observed range of movement at a joint is determined by a variety of factors. The main ones are the muscular tone, the laxity of the collagen that contributes to the joint capsule and surrounding structures, and the shape of the articulating bony surfaces. The first of these is probably neurologically mediated, the latter two are usually genetically determined. In a majority of cases it is probably the mechanical joint instability that produces the articular damage, though the alternative hypothesis is that the osteoarthrosis is initiated by genetic aberrations in the collagen that coincidentally cause lax joints. Clinical and family studies using the Leeds Hyperextensometer will help to clarify this and it remains a possibility that genetic markers may point to those individuals who will be at particular risk of osteoarthrosis should joint hyperlaxity develop.
Detection of Myocardial Scars in Neonatal Infants from Computerized Echocardiographic Texture Analysis
Authors: Kamath M V , Way R C , Ghista D N , Srinivasan T M , Wu C , Smeenk S , Manning C , Cannon J 
Published: February 2007

It has been demonstrated that highly reflectile echoes (HREs) on standard echocardiograms may represent foci of myocardial fibrosis, calcification, or infiltration. A pilot study of the echocardiograms of premature infants by our group has indicated the presence of HREs in many stressed infants. We have subsequently shown that these HREs correspond to myocardial scarring or necrosis. By studying normal two-dimensional echocardiograms and those with visually observed highly reflectile echoes (HREs), we have been able to develop echo-intensity ranges for normal neonatal myocardium and suspected foci of necrosis. An amplitude analysis of the intensity levels of these highly reflectile areas (HREs) in the echocardiogram has indicated that their mean intensity was significantly higher than the surrounding healthy myocardial areas. Significant correlation was found between these highly reflectile echo zones and calcified or necrotic tissue based on postmortem pathological examination. An objective method of quantifying the ultrasonic reflection amplitude has thereby been developed by us, based on image analysis of the echograms available from the B-scan system. Algorithms have been developed for evaluating the greylevels (or echo intensities or reflection amplitudes) of the pixels, normalizing them with respect to the reflection amplitude of the pericardium, and then printing out the grey-level distribution over an image. Appropriate software has been developed to designate scarred myocardial segments, based on the mean and standard deviation of the selected region on the echo image in comparison with these values for the pericardium.
Syringe Pump Design
Authors: Wadham Paul 
Published: February 2007

With the evolution of special care baby, intensive care, and coronary care units over the last decade, there has developed a need for greater accuracy in the control of increasingly potent infusions. The design of bedside syringe pump infusers that administer the contents of a syringe to a patient at a constant and predetermined rate will be considered in terms of their ergonomics, control, and safety. Syringe pump design has evolved over the past few years from simple mechanised forms of syringe driving to very sophisticated and precisely-controlled drive systems capable of high volumetric accuracy over a wide range of clinical conditions and sustained for long time periods. This has led to the development of new and critical forms of drug therapy. In addition, important progress has been made in the safety and reliability aspects of syringe pump design. Modern syringe pumps are expected to have fail-safe electronics to protect the patient in the event of a fault occurring. With the advent of modern microprocessor techniques, future syringe pumps can be expected to incorporate further sophisticated operational and safety enhancements, whilst remaining simple to operate. Typical safety enhancements could include the incorporation of a variable pressure sensor to protect against unwanted pressure build up in the IV line, the use of absolute linear encoding techniques for control and monitoring of the infusion, and the increasing use of self-tests and diagnostics to aid the user. Operational enhancements could include the ability to support pharmacokinetic techniques, as well as closed loop drug therapy and remote computer control. Whilst this suggests that infusion therapy might become too sophisticated for day to day use, comprehensive interactive instructions and diagnostic aids would contribute greatly to ease of use. Good user training will be of increasing importance to maximize the benefits of the advances in syringe pump design.
Parenteral Nutrition and Infusion Technology
Authors: Wood Susanne R 
Published: February 2007

Parenteral nutrition is used to support life during a period of intestinal failure when nutrients cannot be absorbed through the gastro-intestinal tract. Hypertonic solutions of amino-acids and glucose, with added vitamins, electrolytes, and trace elements, are administered, together with isotonic fat emulsions, directly into the superior vena cava or right atrium of the heart. Access to the central venous circulation is obtained by the insertion of a soft, silicone rubber catheter into a neck or arm vein. Life threatening metabolic disturbance, infection, and catheter-associated complications may occur in the absence of attention to detail. To prevent sudden changes in fluid and electrolyte status, and blood glucose levels, a method of flow control must be selected which remains accurate when infusing fluids of varying density or when the patient is mobile. It is important that the method selected does not allow high pressures to develop in the soft intravenous catheter and can be managed safely in the intensive care unit, the general ward, or by the patient in his own home.
Continuous Insulin Infusion
Authors: Pickup John C 
Published: February 2007

A major new approach to the improvements of metabolic control in insulin-dependent diabetic patients is the replacement of insulin by delivery systems which simulate non-diabetic insulin secretory patterns. In the last ten years a number of open-loop, extracorporeal, portable infusion pumps have been used in research trials tasting from a few days to several years. Routine treatment by insulin pumps is now being considered. Most infusers are syringe-drivers, although peristaltic and reciprocating pumps have also been employed. All are based on a slow, basal delivery rate, supplemented by insulin boosts at meal-times. The most popular infusion route is via the subcutaneous tissue. Technological development is concentrating on miniaturisation, alarms (such as low battery state and motor over-run) and more flexible/programmable delivery rates. Attempts are in progress to ‘close the loop’ using an implanted glucose sensor. Most electrodes are amperometric or potentiometric enzyme sensors employing immobilised glucose oxidase. Encouraging in vivo results are being obtained from a novel amperometric biosensor which uses ferrocene to mediate electron transfer. The most likely implantation site is the subcutaneous tissue.
A Review of Some of the Rheumatological Problems and Engineering Capabilities
Authors: Bird H A 
Published: February 2007

Up to 150 different diseases can affect the joints and musculoskeletal system. These range from musculoskeletal rheumatism, which is self-limiting and causes no demonstrable joint pathology, through metabolic and degenerative joint diseases to the chronic auto-immune disorders of inflammation of which rheumatoid arthritis is the most common in the United Kingdom, and the most severe. Many of these conditions are characterised by inflammation which has the cardinal symptoms of heat, swelling, pain, erythema, and loss of function. Rheumatologists require accurate and objective methods of measuring all these parameters at a large number of joints, each of different anatomical structure, in order to adequately monitor the course of the disease and its response to treatment. Complementary information is required on the function of muscles, ligaments, tendons, and bone, as well as the joints. Although the individual analysis of each of these components is likely to provide the most information on disease pathogenesis, functional evaluation which integrates many of these variables simultaneously is likely to provide most information on the patient's progress. Both are needed. In the realm of therapeutics, a wide range of prostheses, all of sound bioengineering design, are available. Greater problems arise in the matching of different prostheses to an individual patients needs and in their fixation in a patient whose disease is constantly altering the joint contour. The attention of bioengineers is now being directed towards the design of replacements for other parts of the joint and musculoskeletal system, for example, ligaments. Adequate methods of testing these under repetitive stress and of measuring the improvement they provide will be increasingly required.