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Orthopaedic Proceedings
Vol. 103-B, Issue SUPP_2 | Pages 62 - 62
1 Mar 2021
Talbott H Wilkins R Cooper R Redmond A Brockett C Mengoni M
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Abstract

OBJECTIVE

Flattening of the talar dome is observed clinically in haemarthropathy as structural and functional changes advance but has not been quantified yet. In order to confirm clinical observation, and assess the degree of change, morphological measurements were derived from MR images.

METHODS

Four measurements were taken, using ImageJ (1.52v), from sagittal MRI projections at three locations – medial, lateral and central: Trochlear Tali Arc Length (TaAL), Talar Height (TaH), Trochlear Tali Length (TaL), and Trochlear Tali Radius (TaR). These measurements were used to generate three ratios of interest: TaR:TaAL, TaAL:TaL, and TaL:TaH. With the hypothesis of a flattening of the talar dome with haemarthropathy, it was expected that TaR:TaAL and TaL:TaH should be greater for haemophilic ankles, and TaAL:TaL should be smaller. A total of 126 MR images (ethics: MEEC 18–022) were included to assess the difference in those ratios between non-diseased ankles (33 images from 11 volunteers) and haemophilic ankles (93 images from 8 patients’ ankles). Non-diseased control measurements were compared to literature to assess the capacity of doing measurements on MRI instead of radiographs or CT.


Orthopaedic Proceedings
Vol. 101-B, Issue SUPP_10 | Pages 15 - 15
1 Oct 2019
Saunders F Gregory J Pavlova A Muthuri S Hardy R Martin K Barr R Adams J Kuh D Aspden R Cooper R Ireland A
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Purpose and Background

Both overall spine shape and the size and shape of individual vertebrae undergo rapid growth and development during early childhood. Motor development milestones such as age of walking influence spine development, with delayed ambulation linked with spinal conditions including spondylolysis. However, it is unclear whether associations between motor development and spine morphology persist into older age. Therefore, these associations were examined using data from the MRC National Survey of Health and Development, a large nationally-representative British cohort, followed up since birth in 1946.

Methods and Results

Statistical shape modelling was used to characterise spinal shape (L5-T10) and identify modes of variation in shape (SM) from dual energy x-ray absorptiometry images of the spine taken at age 60–64 years (N=1327 individuals; 51.8% female). Associations between walking age in months (reported by mothers at 2 years) and SMs were examined with adjustment for sex, birthweight, socioeconomic position, height, lean mass and fat mass.

Later onset of independent walking was weakly associated with greater lordosis (SM1; P=0.05) and more uniform antero-posterior vertebral size along the spine (SM6, P=0.07). Later walking age was also associated with smaller relative anterior-posterior vertebral dimensions (SM3) among women whereas the opposite was found for men (P <0.01 for sex interaction).


Orthopaedic Proceedings
Vol. 100-B, Issue SUPP_11 | Pages 29 - 29
1 Aug 2018
Stockley I Partridge D Cooper R Townsend R
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No single test is 100% sensitive and specific for the diagnosis of prosthetic joint infection. Joint aspiration is currently the only preoperative investigation that can establish the identity of the infecting organism and its antibiotic susceptibilities. Frequently when attempting to aspirate a joint a ‘dry tap occurs as fluid cannot be aspirated. In this situation, normal saline may be injected into the joint and then reaspirated to provide fluid for culture.

The aim of this study was to ascertain the diagnostic accuracy of culture of joint aspiratie with or without saline reaspiration in the event of a dry tap.

A retrospective analysis of 580 hip and knee aspirations in patients deemed to have moderate-high risk of infection and ultimately proceeded to revision arthroplasty over 12 years at a large quaternary referral centre where pre operative aspiration is routine.

Fluid was aspirated in 313 (54%) cases and dry taps in which saline injection reaspiration was performed occurred in 267 (46%) cases. Overall sensitivity and specificity of diagnostic aspiration were 84% (78–89%) and 85% (81–88%) respectively. Sensitivity and specificity of saline injection-reaspiration after dry tap were 87% (79–82%) and 79% (72–84%) compared to 81% (71–88%) and 90% (85–93%) for direct aspiration.

Pre operative joint aspiration and culture is a sensitive and specific test for the confirmation of diagnosis in patients at a moderate to high risk of prosthetic joint infection. Culture of saline injection-reaspiration also provides accurate diagnostic information in the event of a dry tap. Both methods allow susceptibility testing of relevant organisms and are therefore able to guide peri-operative and cement instilled antibiotic therapy.

Culture of pre operative joint aspirates provides sensitive and specific diagnostic information including antimicrobial susceptibility results.

Saline injection-reaspiration is a useful additional technique in those patients in whom fluid cannot be aspirated.


The Bone & Joint Journal
Vol. 100-B, Issue 6 | Pages 749 - 754
1 Jun 2018
Partridge DG Winnard C Townsend R Cooper R Stockley I

Aims

The aim of this study was to establish the diagnostic accuracy of culture of joint aspirate with and without saline injection-reaspiration.

Patients and Methods

This is a retrospective analysis of 580 hip and knee aspirations in patients who were deemed to have a moderate to high risk of infection, and who subsequently proceeded to revision arthroplasty over a period of 12 years. It was carried out at a large quaternary referral centre where preoperative aspiration is routine.


Orthopaedic Proceedings
Vol. 100-B, Issue SUPP_6 | Pages 53 - 53
1 Apr 2018
Cooper R Williams S Mengoni M Jones A
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Introduction

Geometric variations of the hip joint can give rise to repeated abnormal contact between the femur and acetabular rim, resulting in cartilage and labrum damage. Population-based geometric parameterisation can facilitate the flexible and automated in silico generation of a range of clinically relevant hip geometries, allowing the position and size of cams to be defined precisely in three dimensions. This is advantageous compared to alpha angles, which are unreliable for stratifying populations by cam type. Alpha angles provide an indication of cam size in a single two-dimensional view, and high alpha angles have been observed in asymptomatic individuals.

Parametric geometries can be developed into finite element models to assess the potential effects of morphological variations in bone on soft tissue strains. The aim of this study was to demonstrate the capabilities of our parameterisation research tool by assessing impingement severity resulting from a range of parametrically varied femoral and acetabular geometries.

Methods

Custom made MATLAB (MathWorks) and Python codes[1] were used to generate bone surfaces, which were developed into finite element models in Abaqus (SIMULIA). Parametric femoral surfaces were defined by a spherical proximal head and ellipse sections through the neck/cam region. This method produced surfaces that were well fitted to bone geometry segmented from CT scans of cam patients and capable of producing trends in results similar to those found using segmented models. A simplified spherical geometry, including the labrum and acetabular cartilage, represented the acetabulum.

Femoral parameters were adjusted to define relevant variations in cam size and position. Two radii (small and large cams) and two positions (anterior and superior cams) were defined resulting in four models. Alpha angles of these parametric femurs were measured in an anterior-posterior view and a cross-table lateral view using ImageJ (NIH). A further model was developed using a femur with a medium cam size and position, and the level of acetabular coverage and labrum length were varied.

Bones were modelled as rigid bodies and soft tissues were modelled as transversely isotropic linearly elastic materials. With the acetabulum fully constrained in all cases, the femurs were constrained in translation and rotated to simulate flexion followed by internal rotation to cause impingement against the labrum.


Orthopaedic Proceedings
Vol. 100-B, Issue SUPP_2 | Pages 20 - 20
1 Feb 2018
Pavlova A Muthuri S Saunders F Hardy R Gregory J Barr R Martin K Adams J Kuh D Cooper R Aspden R
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Purpose

To investigate associations between sagittal thoracolumbar spine shape with sex and measures of adiposity throughout adulthood.

Methods

Thoracolumbar spine shape was characterised using statistical shape modelling on lateral dual-energy x-ray absorptiometry images, recorded for vertebral fracture analysis, of the spine from 1529 participants of the MRC National Survey of Health and Development, acquired at age 60–64 years. Associations between spine shape modes (SM) and 1) sex, 2) contemporaneous measures of overall and central adiposity (indicated by body mass index and waist circumference, respectively), 3) changes in total and central adiposity during earlier stages of adulthood and age at onset of overweight, were investigated.


Orthopaedic Proceedings
Vol. 86-B, Issue SUPP_I | Pages 69 - 69
1 Jan 2004
Ali F Kerry RM Cooper R Wilkinson JM Norman PA Stockley I
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Purpose: The role of hip aspiration as a preoperative investigation for the painful hip remains controversial. Since 1999, we have performed hip aspiration under local anaesthetics in the X-ray department. This paper reviews our experience with this technique.

Results: Hip aspirations were carried out subsequently on 182 patients from November 1999 to November 2002. Out of 68 patients that underwent revision hip surgery, 63 were included in the study. Three of the five patients excluded had received antibiotics at induction prior to obtaining the operative samples and two did not have any operative samples taken at the time of surgery. Fifteen (23.8%) of the 63 hips were found to be infected based on operative tissue cultures. The sensitivity and specificity of the test were 80% and 87.5%, respectively. Positive and negative predictive values were 66.6% and 93.3% respectively and the accuracy was 85.7%.

Conclusion: Hip aspiration in the Radiology department is a simple, cost effective and reliable preoperative test when used selectively. When used in combination with other laboratory and radiological investigation it can act as an important preoperative investigation in the diagnosis of sepsis. There is an added advantage of identifying the microorganism along with its antibiotic sensitivities. This can guide clinicians in choosing the correct antibiotic for the cement and also for the postoperative antibiotic therapy.


Orthopaedic Proceedings
Vol. 84-B, Issue SUPP_I | Pages - 94
1 Mar 2002
Crossman K Al-Omar A Oldham J Cooper R
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Paraspinal muscle dysfunction is associated with chronic low back pain (CLBP) in prospective studies, some authors suggesting a primary role for muscle in CLBP development. To investigate this possibility, we compared paraspinal muscle electromyographic (EMG) fatigue characteristics with fibre-type composition in ambulant, male CLBP patients and male controls of similar age.

Thirty-five patients with Chronic Pain Grades of III (a high level of residual function, despite pain, negated the effects of disuse atrophy), and 32 controls were studied. Paraspinal surface EMG signals were recorded from the T10/11 and L4/5 regions bilaterally during standard isometric endurance tests. The rate of fatigue-induced median frequency (MF) decline was calculated from the power spectrum. Percutaneous paraspinal muscle biopsies permitted the determination of muscle fibre-type characteristics.

MF decline, mean fibre size and relative area occupied by fibre types did not differ significantly between groups.

The paraspinal muscles of ambulant CLBP patients demonstrate no excessive fatigability, when assessed by EMG, nor a relative paucity in the area occupied by either fibre type. Patients developing CLBP do not demonstrate an adverse paraspinal muscle fibre-type composition.