Publications by authors named "Jon Clarke"

45 Publications

Dynamic stability during stair negotiation after total knee arthroplasty.

Clin Biomech (Bristol, Avon) 2021 Jul 10;87:105410. Epub 2021 Jun 10.

Department of Biomedical Engineering, University of Strathclyde, Glasgow, Scotland, UK.

Background: The assessment of dynamic stability is crucial for the prevention of falls in the elderly and people with functional impairments. Evidence that total knee arthroplasty improves balance in patients with severe osteoarthritis is scarce and no information exists about how the surgery affects dynamic stability during stair negotiation.

Methods: This study aims to investigate if patients before and one year after surgery are less stable compared to asymptomatic controls. Seventeen control and twenty-seven patient participants with end-stage knee osteoarthritis that were scheduled to undergo unilateral total knee arthroplasty were recruited in this study. Participants' assessment was carried out by means of marker-based optical full-body motion capture with force platforms. The extrapolated Centre of mass and the margin of stability metrics were used to examine dynamic stability during stair ascent and descent.

Findings: Patient participants, during both pre-operative and post-operative assessments, were equally balanced to the asymptomatic controls during stair gait (p > .188). Additionally, the patients' overall stability did not improve significantly one year after arthroplasty surgery (p > .252).

Interpretation: Even if pain from arthritis and fear of falling is decreased following surgery, our results indicate that stability in stair walking in not affected by osteoarthritis and total knee arthroplasty.

Clinical Trial Registration Number: NCT02422251.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.clinbiomech.2021.105410DOI Listing
July 2021

Identifying car ingress movement strategies before and after total knee replacement.

Int Biomech 2020 12;7(1):9-18

Department of Biomedical Engineering, University of Strathclyde , Glasgow, Scotland.

: Post-operative performance of knee bearings is typically assessed in activities of daily living by means of motion capture. Biomechanical studies predominantly explore common tasks such as walking, standing and stair climbing, while overlooking equally demanding activities such as embarking a vehicle. : The aim of this work is to evaluate changes in the movement habits of patients after total knee arthroplasty surgery in comparison to healthy age-matched control participants. : A mock-up car was fabricated based on the architecture of a common vehicle. Ten control participants and 10 patients with severe osteoarthritis of the knee attended a single- and three-motion capture session(s), respectively. Participants were asked to enter the car and sit comfortably adopting a driving position. Three trials per session were used for the identification of movement strategies by means of hierarchical clustering. Task completion time was also measured. : Patients' movement behaviour didn't change significantly following total knee arthroplasty surgery. Control participants favoured different movement strategies compared to patients post-operatively. Group membership, height and sidedness of the affected joint were found to be non-significant in task completion time. : This study describes an alternative movement identification technique for the analysis of the ingress movement that may be used to clinically assess knee bearings and aid in movement simulations and vehicle design.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/23335432.2020.1716847DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8130714PMC
December 2020

The effect of hospital case volume on re-revision following revision total knee arthroplasty.

Bone Joint J 2021 Apr;103-B(4):602-609

Department of Orthopaedics, University of Edinburgh, Edinburgh, UK.

Aims: The aim of this study was to measure the effect of hospital case volume on the survival of revision total knee arthroplasty (RTKA).

Methods: This is a retrospective analysis of Scottish Arthroplasty Project data, a nationwide audit which prospectively collects data on all arthroplasty procedures performed in Scotland. The primary outcome was RTKA survival at ten years. The primary explanatory variable was the effect of hospital case volume per year on RTKA survival. Kaplan-Meier survival curves were plotted with 95% confidence intervals (CIs) to determine the lifespan of RTKA. Multivariate Cox proportional hazards were used to estimate relative revision risks over time. Hazard ratios (HRs) were reported with 95% CI, and p-value < 0.05 was considered statistically significant.

Results: From 1998 to 2019, 8,301 patients (8,894 knees) underwent RTKA surgery in Scotland (median age at RTKA 70 years (interquartile range (IQR) 63 to 76); median follow-up 6.2 years (IQR 3.0 to 10.2). In all, 4,764 (53.6%) were female, and 781 (8.8%) were treated for infection. Of these 8,894 knees, 957 (10.8%) underwent a second revision procedure. Male sex, younger age at index revision, and positive infection status were associated with need for re-revision. The ten-year survival estimate for RTKA was 87.3% (95% CI 86.5 to 88.1). Adjusting for sex, age, surgeon volume, and indication for revision, high hospital case volume was significantly associated with lower risk of re-revision (HR 0.78 (95% CI 0.64 to 0.94, p < 0.001)). The risk of re-revision steadily declined in centres performing > 20 cases per year; risk reduction was 16% with > 20 cases; 22% with > 30 cases; and 28% with > 40 cases. The lowest level of risk was associated with the highest volume centres.

Conclusion: The majority of RTKA in Scotland survive up to ten years. Increasing yearly hospital case volume above 20 cases is independently associated with a significant risk reduction of re-revision. Development of high-volume tertiary centres may lead to an improvement in the overall survival of RTKA. Cite this article:  2021;103-B(4):602-609.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1302/0301-620X.103B4.BJJ-2020-1901.R1DOI Listing
April 2021

Differences in the vertical and horizontal force-velocity profile between academy and senior professional rugby league players, and the implications for strength and speed training.

J Sports Med Phys Fitness 2021 Mar 26. Epub 2021 Mar 26.

Department of Sport and Exercise Science, University of Chester, Chester, UK.

Background: This study compared the vertical and horizontal force-velocity (FV) profile of academy and senior rugby league players.

Methods: Nineteen senior and twenty academy players from one professional club participated in this study. The vertical FV profile was determined using a series of loaded squat jumps (0.4 to 80 kg) with jump height recorded. The horizontal FV profile involved a 30-m over-ground sprint with split times recorded at 5, 10, 15, 20 and 30 m. Theoretical maximal force (F0), velocity (V0) and power (Pmax), optimal F0 and V0, and activity specific variables (e.g. vertical FV imbalance) were determined.

Results: Absolute F0 and Pmax from the vertical and horizontal profile were moderately different between groups (standardised mean difference (SMD) = 0.64-1.20, P <0.001-0.026), whilst for V0, differences were small (SMD = 0.33-0.41, P = 0.149-0.283). Differences in relative F0, Pmax and optimal F0 during both assessments were trivial to moderate (SMD = 0.03-0.82, P = 0.021-0.907).

Conclusions: These results highlight senior and academy players present with different FV profiles and highlight some potential developmental opportunities for senior and academy rugby league players that sport scientists, strength and conditioning and rugby coaches can implement when designing programmes and considering long-term athlete development.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.23736/S0022-4707.21.12036-5DOI Listing
March 2021

National operating volume for primary hip and knee arthroplasty in the COVID-19 era: a study utilizing the Scottish arthroplasty project dataset.

Bone Jt Open 2021 Mar;2(3):203-210

Department of Orthopaedics, University of Edinburgh, Edinburgh, UK.

Aims: The COVID-19 pandemic led to a national suspension of "non-urgent" elective hip and knee arthroplasty. The study aims to measure the effect of the COVID-19 pandemic on total hip arthroplasty (THA) and total knee arthroplasty (TKA) volume in Scotland. Secondary objectives are to measure the success of restarting elective services and model the time required to bridge the gap left by the first period of suspension.

Methods: A retrospective observational study using the Scottish Arthroplasty Project dataset. All patients undergoing elective THAs and TKAs during the period 1 January 2008 to 31 December 2020 were included. A negative binomial regression model using historical case-volume and mid-year population estimates was built to project the future case-volume of THA and TKA in Scotland. The median monthly case volume was calculated for the period 2008 to 2019 (baseline) and compared to the actual monthly case volume for 2020. The time taken to eliminate the deficit was calculated based upon the projected monthly workload and with a potential workload between 100% to 120% of baseline.

Results: Compared to the period 2008 to 2019, primary TKA and THA volume fell by 61.1% and 53.6%, respectively. Since restarting elective services, Scottish hospitals have achieved approximately 40% to 50% of baseline monthly activity. With no changes in current workload, by 2021 there would be a reduction of 9,180 and 10,170 for THA and TKA, respectively. Conversely, working at 120% baseline monthly output, it would take over four years to eliminate the deficit for both TKA and THA.

Conclusion: This national study demonstrates the significant impact that COVID-19 pandemic has had on overall THA and TKA volume. In the six months after resuming elective services, Scottish hospitals averaged less than 50% normal monthly output. Loss of operating capacity will increase treatment delays and likely worsen overall morbidity. Cite this article:  2021;2(3):203-210.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1302/2633-1462.23.BJO-2020-0193.R1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8009902PMC
March 2021

Implant design affects walking and stair navigation after total knee arthroplasty: a double-blinded randomised controlled trial.

J Orthop Surg Res 2021 Mar 6;16(1):177. Epub 2021 Mar 6.

Department of Biomedical Engineering, University of Strathclyde, Glasgow, Scotland.

Background: Dissimilar total knee arthroplasty implant designs offer different functional characteristics. This is the first work in the literature to fully assess the Columbus ultra-congruent mobile (UCR) system with a rotating platform.

Methods: This is a double-blinded randomised controlled trial, comparing the functional performance of the low congruent fixed (CR DD), ultra-congruent fixed (UC) and UCR Columbus Total Knee Systems. The pre-operative and post-operative functional performance of twenty-four osteoarthritic patients was evaluated against nine control participants when carrying out everyday tasks. Spatiotemporal, kinematic and kinetic gait parameters in walking and stair navigation were extracted by means of motion capture.

Results: The UC implant provided better post-operative function, closely followed by the UCR design. However, both the UC and UCR groups exhibited restricted post-operative sagittal RoM (walking, 52.1 ± 4.4° and 53.2 ± 6.6°, respectively), whilst patients receiving a UCR implant did not show an improvement in their tibiofemoral axial rotation despite the bearing's mobile design (walking, CR DD 13.2 ± 4.6°, UC 15.3 ± 6.7°, UCR 13.5 ± 5.4°). Patients with a CR DD fixed bearing showed a statistically significant post-operative improvement in their sagittal RoM when walking (56.8 ± 4.6°).

Conclusion: It was concluded that both ultra-congruent designs in this study, the UC and UCR bearings, showed comparable functional performance and improvement after TKA surgery. The CR DD group showed the most prominent improvement in the sagittal RoM during walking.

Trial Registration: The study is registered under the clinical trial registration number: NCT02422251 . Registered on April 21, 2015.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13018-021-02311-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7936496PMC
March 2021

Protrusion-Mediated Signaling Regulates Patterning of the Developing Nervous System.

Front Cell Dev Biol 2020 29;8:579073. Epub 2020 Sep 29.

Developmental Biology and Cancer, UCL GOS Institute of Child Health, University College London, London, United Kingdom.

During brain development, the tissue pattern and specification are the foundation of neuronal circuit formation. Contact-mediated lateral inhibition is well known to play an important role in determining cell fate decisions in the nervous system by either regulating tissue boundary formation or the classical salt-and-pepper pattern of differentiation that results from direct neighboring cell contacts. In many systems, however, such as the notum, wing, zebrafish pigmented cells, and zebrafish spinal cord, the differentiation pattern occurs at multiple-cell diameter distances. In this review, we discuss the evidence and characteristics of long-distance patterning mechanisms mediated by cellular protrusions. In the nervous system, cellular protrusions deliver the Notch ligand Delta at long range to prevent cells from differentiating in their vicinity. By temporal control of protrusive activity, this mechanism can pattern differentiation in both space and time.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fcell.2020.579073DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7550624PMC
September 2020

3D biofabrication for soft tissue and cartilage engineering.

Med Eng Phys 2020 08 9;82:13-39. Epub 2020 Jul 9.

Department of Biomedical Engineering, Wolfson Building, University of Strathclyde, 106 Rottenrow, Glasgow G4 0NW, United Kingdom. Electronic address:

Soft tissue injuries (STIs) affect patients of all age groups and represent a common worldwide clinical problem, resulting from conditions including trauma, infection, cancer and burns. Within the spectrum of STIs a mixture of tissues can be injured, ranging from skin to underlying nerves, blood vessels, tendons and cartilaginous tissues. However, significant limitations affect current treatment options and clinical demand for soft tissue and cartilage regenerative therapies continues to rise. Improving the regeneration of soft tissues has therefore become a key area of focus within tissue engineering. As an emerging technology, 3D bioprinting can be used to build complex soft tissue constructs "from the bottom up," by depositing cells, growth factors, extracellular matrices and other biomaterials in a layer-by-layer fashion. In this way, regeneration of cartilage, skin, vasculature, nerves, tendons and other bodily tissues can be performed in a patient specific manner. This review will focus on recent use of 3D bioprinting and other biofabrication strategies in soft tissue repair and regeneration. Biofabrication of a variety of soft tissue types will be reviewed following an overview of available cell sources, bioinks and bioprinting techniques.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.medengphy.2020.06.003DOI Listing
August 2020

Montmorency tart cherry juice does not reduce markers of muscle soreness, function and inflammation following professional male rugby League match-play.

Eur J Sport Sci 2021 Jul 6;21(7):1003-1012. Epub 2020 Aug 6.

Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK.

Rugby League (RL) match-play causes muscle damage, inflammation and symptoms of fatigue. To facilitate recovery, nutritional interventions are often employed, including Montmorency cherry juice (MC). We assessed the effects of MC on recovery following RL match-play in eleven male professional RL players who played in two matches (7-days apart) with MC or placebo (PLB) supplemented for 5-days pre-match, matchday and 2-days post-match. Blood was collected 48h pre-match, half-time, within 30-mins of full-time and 48h post-match to assess Interleukin concentrations (IL-6, -8 -10). Self-reported sleep, fatigue, mood, stress, and muscle-soreness were assessed 24h pre and 24 and 48h post-matches with muscle function assessed 48h pre and 48h post-match. No differences in distance covered (6334 ± 1944 Vs 6596 ± 1776m) and total collisions (28 ± 11 Vs 29 ± 13) were observed between both matches. There was a small albeit significant increase in IL-6, -8 and -10 concentrations pre to post-match in both PLB (IL-6: 0.83 ± 0.92 Vs 2.91 ± 1.40, IL-8: 2.16 ± 1.22 Vs 3.91 ± 1.61 and IL-10: 2.51 ± 2.14 Vs 0.61 ± 0.50 pgmL) and MC groups (IL-6: 0.53 ± 0.53 Vs 2.24 ± 1.73, IL-8: 1.85 ± 0.96 Vs 3.46 ± 1.12 and IL-10: 0.48 ± 0.50 Vs 2.54 ± 2.10 pgmL), although there were no significant differences between groups (<0.05). Likewise, there was a small but significant increase in muscle soreness (=0.01) and reduction in CMJ (=0.003) with no significant differences between groups. No significant changes in sleep, fatigue or mood (>0.05) were observed pre to post-match or between groups. These data suggest MC does not affect the modest changes observed in cytokine responses and markers of recovery from RL match-play.Keywords: Team Sport, Nutrition, Performance, Recovery.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/17461391.2020.1797181DOI Listing
July 2021

Development of anthropometric characteristics in professional Rugby League players: Is there too much emphasis on the pre-season period?

Eur J Sport Sci 2020 Sep 4;20(8):1013-1022. Epub 2019 Dec 4.

Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK.

Rugby League is a team sport requiring players to experience large impact collisions, thus requiring high amounts of muscle mass. Many players (academy and senior) strive to increase muscle mass during the pre-season, however, quantification of changes during this period have not been thoroughly investigated. We therefore assessed changes in body-composition using Dual X-Ray Absorptiometry (DXA) in eleven academy players over three successive pre-seasons and ninety-three senior players from four different European Super League clubs prior to, and at the end of, a pre-season training period. There was no meaningful change in lean mass of the academy players during any of the pre-season periods (year 1 = 72.3 ± 7.1-73.2 ± 7.2kg; ES 0.05, year 2 = 74.4 ± 6.9-75.5 ± 6.9kg; ES 0.07, year 3 = 75.9 ± 6.7-76.8 ± 6.6kg; ES 0.06) with changes only occurring over the three-year study period (72.3-75.9kg; ES = 0.22). Senior players showed changes in all characteristics during the pre-season period (total mass = 95.1-95.0kg; ES -0.01, lean mass = 74.6-75.1kg; ES 0.07, fat mass = 13.6-12.9kg; ES -0.17, body fat percentage = 14.8-14.1%; ES -0.19). These data suggest that academy players need time to develop towards profiles congruent with senior players. Moreover, once players reach senior level, body-composition changes are during the pre-season and therefore teams may need to individualise training for players striving to gain muscle mass by reducing other training loads.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/17461391.2019.1695953DOI Listing
September 2020

3D bioprinting of mature bacterial biofilms for antimicrobial resistance drug testing.

Biofabrication 2019 09 13;11(4):045018. Epub 2019 Sep 13.

Centre for Molecular Nanometrology, Department of Pure and Applied Chemistry, Technology and Innovation Centre, University of Strathclyde, 99 George Street, Glasgow, G1 1RD, United Kingdom.

The potential to bioprint and study 3D bacterial biofilm constructs could have great clinical significance at a time when antimicrobial resistance is rising to dangerously high levels worldwide. In this study, clinically relevant bacterial species including Escherichia coli, Staphylococcus aureus (MSSA), Methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa were 3D bioprinted using a double-crosslinked alginate bioink to form mature bacteria biofilms, characterized by confocal laser scanning microscopy (CLSM) and fluorescent staining. Solid and porous bacteria-laden constructs were reproducibly bioprinted with thicknesses ranging from 0.25 to 4 mm. We demonstrated 3D bioprinting of thicker biofilms (>4 mm) than found in currently available in vitro models. Bacterial viability was excellent in the bioprinted constructs, with CLSM observation of bacterial biofilm production and maturation possible for at least 28 d in culture. Importantly, we observed the complete five-step biofilm life cycle in vitro following 3D bioprinting for the first time, suggesting the formation of mature 3D bioprinted biofilms. Bacterial growth was faster in thinner, more porous constructs whilst constructs crosslinked with BaCl concentrations of above 10 mM had denser biofilm formation. 3D MRSA and MSSA biofilm constructs were found to show greater resistance to antimicrobials than corresponding two-dimensional (2D) cultures. Thicker 3D E. coli biofilms had greater resistance to tetracycline than thinner constructs over 7 d of treatment. Our methodology allowed for the precise 3D bioprinting of self-supporting 3D bacterial biofilm structures that developed biofilms during extended culture. 3D biofilm constructs containing bacterial biofilms produce a model with much greater clinical relevance compared to 2D culture models and we have demonstrated their use in antimicrobial testing.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1088/1758-5090/ab37a0DOI Listing
September 2019

Microfluidic Fabrication of Biomimetic Helical Hydrogel Microfibers for Blood-Vessel-on-a-Chip Applications.

Adv Healthc Mater 2019 07 13;8(13):e1900435. Epub 2019 May 13.

College of Chemistry, Chemical Engineering and Material Science, Orthopaedic Institute, Soochow University, Suzhou, Jiangsu, 215006, China.

Nature has created many perfect helical microstructures, including DNA, collagen fibrils, and helical blood vessels, to achieve unique physiological functions. While previous studies have developed a number of microfabrication strategies, the preparation of complex helical structures and cell-laden helical structures for biomimetic applications remains challenging. In this study, a one-step microfluidics-based methodology is presented for preparing complex helical hydrogel microfibers and cell-laden helical hydrogel microfibers. Several types of complex helical structures, including multilayer helical microfibers and superhelical hollow microfibers with helical channels, are prepared by simply tuning the flow rates or modifying the geometry of microfluidic device. With the decent perfusability, the hollow microfibers may simulate the structural characteristics of helical blood vessels and create swirling blood flow in a blood-vessel-on-chip setup. Such hydrogel-based helical microstructures may potentially be used in areas such as blood vessel tissue engineering, organ-on-chips, drug screening, and biological actuators.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/adhm.201900435DOI Listing
July 2019

A new landmark for measuring tibial component rotation after total knee arthroplasty.

Knee 2019 Jun 27;26(3):779-786. Epub 2019 Mar 27.

Department of Orthopaedics, Golden Jubilee National Hospital, Agamemnon Street, Clydebank, West Dunbartonshire G81 4DY, UK. Electronic address:

Background: Existing methods for assessment of total knee arthroplasty (TKA) component rotation on computed tomography (CT) scans are complex, especially in relation to the tibial component. Anecdotal evidence from our practice pointed towards a potential new landmark. The study aims were to check the prevalence of this landmark, define tibial component rotation in relation to it and demonstrate its reliability.

Methods: Two hundred and eleven CTs undertaken following TKA were reviewed for presence of the landmark. A protocol to measure tibial component rotation in relation to this landmark was developed and the rotation measured using this method and Berger's protocol. Thirty one of the 211 CT scans were measured twice by two observers. Reliability was calculated using the Intraclass Correlation Coefficient (ICC).

Results: The new landmark of a flat area on the lateral cortex of the tibia inferior to the tibial component was identified on all scans. Median tibial component rotation measured using our protocol was 0.0° ± 5.4° and -9.2° ± 5.5° using Berger's protocol. Intra-observer reliability with the new method was excellent (ICCs of 0.899 and 0.871) and inter-observer reliability was good (ICCs of 0.734 and 0.836).

Conclusions: The new landmark had a very high prevalence and could be used to define tibial component rotation. This measurement of tibial component rotation had acceptable reliability. This landmark has potential for use in the radiological assessment of tibial component rotation following TKA. Further work is required to determine its relationship to anatomical structures and symptoms of tibial component mal-rotation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.knee.2018.09.002DOI Listing
June 2019

The ionic contribution of proteoglycans to mechanical stiffness of the meniscus.

Med Eng Phys 2019 02 27;64:23-27. Epub 2018 Dec 27.

Biomedical Engineering Unit, Wolfson Building, University of Strathclyde, 106 Rottenrow, Glasgow, G4 0NW, UK.

Load transmission is an important function of the meniscus. In articular cartilage, proteoglycans help maintain hydration via negatively charged moieties. We aimed to investigate the influence of electrostatic effects on stiffness of meniscal tissue. Circular discs from bovine menisci of 8 mm diameter and 5 mm thickness were placed within a confined compression chamber. The apparatus was bathed in distilled water, 0.14 M PBS or 3 M PBS before being subjected to 5% ramp compressive strain and held for 300s. FEBio software was used to fit resultant relaxation curves to a non-linear poroviscoelastic model with strain dependent Holmes-Mow permeability. Analysis was conducted using one-way ANOVA with Tukey post-hoc analysis. 10 samples were tested in each solution. Significant differences (p < 0.05) were observed between the values for Young's modulus, zero strain dependent permeability and the viscoelastic coefficient for samples tested in 3 M PBS as compared to deionised water/0.14 M PBS. No significant differences were observed in the strain dependent/stiffening coefficients or the relaxation time. Approximately 79% of the stiffness of the meniscus appears attributable to ionic effects. Ionic effects play a significant role in the mechanical stiffness of the meniscus. It is important to include the influence of ionic effects when developing mathematical models of this tissue.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.medengphy.2018.12.010DOI Listing
February 2019

Lower limb alignment becomes more varus and hyperextended from supine to bipedal stance in asymptomatic, osteoarthritic and prosthetic neutral or varus knees.

Knee Surg Sports Traumatol Arthrosc 2019 May 10;27(5):1635-1641. Epub 2018 Nov 10.

Department of Orthopaedics, Golden Jubilee National Hospital, Agamemnon Street, West Dunbartonshire, Clydebank, G81 4DY, UK.

Purpose: Knee alignment is a fundamental measurement in the assessment, monitoring and surgical management of patients with osteoarthritis. There is a lack of data regarding how static tibiofemoral alignment varies between supine and standing conditions. This study aimed to quantify the relationship between supine and standing lower limb alignment in asymptomatic, osteoarthritic (OA) and prosthetic (TKA) knees.

Methods: A non-invasive position capture system was used to assess knee alignment for 30 asymptomatic controls and 31 patients with OA both before and after TKA. Coronal and sagittal mechanical femorotibial angles were measured supine with the lower limb in extension and in bipedal stance. Changes between conditions were analysed using paired ttests. Vector plots of ankle centre displacement relative to the knee centre from supine to standing were produced to allow three-dimensional visualisation.

Results: All groups showed a trend towards varus and extension when going from supine to standing. Mean change for asymptomatic knees was 1.2° more varus (p = 0.001) and 3.8° more extended (p < 0.001). For OA knees this was 1.1° more varus (p = 0.009) and 5.9° more extended (p < 0.001) and TKA knees 1.9° more varus (p < 0.001) and 5.6° more extended (p < 0.001).

Conclusion: The observed consistent changes in lower limb alignment between supine and standing positions across knee types suggests the soft tissue envelope restraining the knee may have a greater influence on dynamic alignment changes than the underlying bony deformity. This highlights the importance of quantifying soft tissue behaviour when planning, performing and evaluating alignment dependent surgical interventions of the knee. When routinely assessing any type of knee, clinicians should be aware that subtle consistent alignment changes occur under weightbearing conditions and tailor their treatments accordingly.

Level Of Evidence: II.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00167-018-5273-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6527790PMC
May 2019

arthroplasty infection: beware of occult aortitis and malignancy.

Scott Med J 2018 Nov 28;63(4):132-139. Epub 2018 Aug 28.

Consultant Orthopaedic Surgeon, Department of Orthopaedic Surgery, Golden Jubilee National Hospital, UK.

Introduction: The species are responsible for life-threatening conditions such as tetanus, botulism and gas gangrene. is a rare cause of clinical infection, accounting for less than 1% of blood culture samples that test positive for . However, bacteraemia is associated with greater than 60% mortality and in over 80% of cases is associated with an underlying malignancy.

Case Presentation: We present a review of the literature and the first case of an acute arthroplasty infection and concurrent infective aortitis caused by this organism in the absence of an identified underlying malignancy. Early diagnosis and multi-disciplinary input resulted in the patient surviving a rare and potentially fatal infective aortitis and septic arthritis.

Conclusion: This case demonstrates the importance of early systemic investigation to exclude occult infective aortitis in infection. The key role of multi-disciplinary input into the management of this often fatal infection is also discussed along with the requirement to exclude occult gastrointestinal and haematological malignancy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1177/0036933018793525DOI Listing
November 2018

3D bioactive composite scaffolds for bone tissue engineering.

Bioact Mater 2018 Sep 1;3(3):278-314. Epub 2017 Dec 1.

Department of Biomedical Engineering, Wolfson Building, University of Strathclyde, 106 Rottenrow, Glasgow, G4 0NW, United Kingdom.

Bone is the second most commonly transplanted tissue worldwide, with over four million operations using bone grafts or bone substitute materials annually to treat bone defects. However, significant limitations affect current treatment options and clinical demand for bone grafts continues to rise due to conditions such as trauma, cancer, infection and arthritis. Developing bioactive three-dimensional (3D) scaffolds to support bone regeneration has therefore become a key area of focus within bone tissue engineering (BTE). A variety of materials and manufacturing methods including 3D printing have been used to create novel alternatives to traditional bone grafts. However, individual groups of materials including polymers, ceramics and hydrogels have been unable to fully replicate the properties of bone when used alone. Favourable material properties can be combined and bioactivity improved when groups of materials are used together in composite 3D scaffolds. This review will therefore consider the ideal properties of bioactive composite 3D scaffolds and examine recent use of polymers, hydrogels, metals, ceramics and bio-glasses in BTE. Scaffold fabrication methodology, mechanical performance, biocompatibility, bioactivity, and potential clinical translations will be discussed.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.bioactmat.2017.10.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5935790PMC
September 2018

Risk Factors for Surgical Site Infection Following Lower Limb Arthroplasty: A Retrospective Cohort Analysis of 3932 Lower Limb Arthroplasty Procedures in a High Volume Arthroplasty Unit.

J Arthroplasty 2018 06 31;33(6):1861-1867. Epub 2018 Jan 31.

Golden Jubilee National Hospital, Clydebank, United Kingdom.

Background: Surgical site infection (SSI) is a debilitating complication of lower limb arthroplasty with significant morbidity and increased costs. Numerous risk factors are associated with SSI.

Methods: In an effort to identify novel risk factors for SSI, we undertook a retrospective cohort study of 1832 primary total hip arthroplasties and 2100 primary total knee arthroplasties performed in our high volume arthroplasty unit over a 2-year period.

Results: Two risk factors were identified for SSI following total hip arthroplasty: body mass index ≥30 and peri-operative blood transfusion. Eight risk factors were identified for SSI following total knee arthroplasty: hypertension, peri-operative blood transfusion, skin closure using 2-octyl cyanoacrylate, use of oral steroids, reduced serum mean cell volume, reduced mean cell hemoglobin, elevated serum neutrophil count, and use of warfarin or rivaroxaban for venous thromboembolism prophylaxis.

Conclusions: Our work proposes a number of previously undocumented risk factors in relation to SSI. Further investigation is required to ascertain the magnitude of their effect.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.arth.2018.01.037DOI Listing
June 2018

Anaesthetic perspective to 10 cases of paracentral acute middle maculopathy following cataract surgery.

Authors:
Jon Clarke

Clin Exp Ophthalmol 2018 05 28;46(4):449-450. Epub 2017 Dec 28.

Department of Anaesthesia, Flinders Medical Centre, Adelaide, South Australia, Australia.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/ceo.13098DOI Listing
May 2018

Lower limb alignment and laxity measures before, during and after total knee arthroplasty: A prospective cohort study.

Clin Biomech (Bristol, Avon) 2017 Aug 26;47:61-65. Epub 2017 May 26.

Department of Biomedical Engineering, University of Strathclyde, UK. Electronic address:

Background: This study compared knee alignment and laxity in patients before, during and after total knee arthroplasty, using methodologically similar procedures, with an aim to help inform pre-operative planning.

Methods: Eighteen male and 13 female patients were recruited, mean age 66years (51-82) and mean body mass index of 33 (23-43). All were assessed pre- and postoperatively using a non-invasive infrared position capture system and all underwent total knee arthroplasty using a navigation system. Knee kinematic data were collected and comparisons made between preoperative clinical and intraoperative measurements for osteoarthritic knees, and between postoperative clinical and intraoperative measurements for prosthetic knees.

Findings: There was no difference in unstressed coronal mechanical femoral-tibial angles for either osteoarthritic or prosthetic knees. However, for sagittal alignment the knees were in greater extension intraoperatively (osteoarthritic 5.2° p<0.001, prosthetic 7.2° p<0.001). For osteoarthritic knees, both varus and valgus stress manoeuvres had greater angular displacements intraoperatively by a mean value of 1.5° for varus (p=0.002) and 1.6° for valgus (p<0.001). For prosthetic knees, only valgus angular displacement was greater intraoperatively (0.9°, p=0.002).

Interpretation: Surgeons performing total knee arthroplasties should be aware of potential differences in alignment and laxity measured under different conditions to facilitate more accurate operative planning and follow-up.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.clinbiomech.2017.05.013DOI Listing
August 2017

Spatial distribution and characterization of non-apical progenitors in the zebrafish embryo central nervous system.

Open Biol 2017 02;7(2)

Developmental Biology and Cancer Department, UCL Institute of Child Health, London WC1N 1EH, UK

Studies of non-apical progenitors (NAPs) have been largely limited to the developing mammalian cortex. They are postulated to generate the increase in neuron numbers that underlie mammalian brain expansion. Recently, NAPs have also been reported in the retina and central nervous system of non-mammalian species; in the latter, however, they remain poorly characterized. Here, we characterize NAP location along the zebrafish central nervous system during embryonic development, and determine their cellular and molecular characteristics and renewal capacity. We identified a small population of NAPs in the spinal cord, hindbrain and telencephalon of zebrafish embryos. Live-imaging analysis revealed at least two types of mitotic behaviour in the telencephalon: one NAP subtype retains the apical attachment during division, while another divides in a subapical position disconnected from the apical surface. All NAPs observed in spinal cord lost apical contact prior to mitoses. These NAPs express HuC and produce two neurons from a single division. Manipulation of Notch activity reveals that neurons and NAPs in the spinal cord use similar regulatory mechanisms. This work suggests that the majority of spinal NAPs in zebrafish share characteristics with basal progenitors in mammalian brains.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1098/rsob.160312DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5356445PMC
February 2017

Carbohydrate and Caffeine Improves High-Intensity Running of Elite Rugby League Interchange Players During Simulated Match Play.

J Strength Cond Res 2019 May;33(5):1320-1327

University of Chester, Chester, United Kingdom.

Clarke, JS, Highton, J, Close, GL, and Twist, C. Carbohydrate and caffeine improves high-intensity running of elite rugby league interchange players during simulated match play. J Strength Cond Res 33(5): 1320-1327, 2019-The study examined the effects of carbohydrate and caffeine ingestion on simulated rugby league interchange performance. Eight male elite rugby league forwards completed 2 trials of a rugby league simulation protocol for interchange players 7 days apart in a randomized crossover design, ingesting either carbohydrate (CHO; 40 g·h) or carbohydrate and caffeine (CHO-C) (40 g·h + 3 mg·kg) drink. Movement characteristics, heart rate, ratings of perceived exertion (RPE), and countermovement jump (CMJ) height were measured during the protocol. CHO-C resulted in likely to very likely higher mean running speeds (effect size [ES] 0.43-0.75), distance in high-intensity running (ES 0.41-0.64), and mean sprint speeds (ES 0.39-1.04) compared with CHO. Heart rate was possibly to very likely higher (ES 0.32-0.74), and RPE was likely to very likely lower (ES -0.53 to 0.86) with CHO-C. There was a likely trivial to possibly higher CMJ in CHO-C compared with CHO (ES 0.07-0.25). The coingestion of carbohydrate with caffeine has an ergogenic effect to reduce the sense of effort and increase high-intensity running capability that might be used to enhance interchange running performance in elite rugby league players.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1519/JSC.0000000000001742DOI Listing
May 2019

The Assessment of Total Energy Expenditure During a 14-Day In-Season Period of Professional Rugby League Players Using the Doubly Labelled Water Method.

Int J Sport Nutr Exerc Metab 2016 Oct 24;26(5):464-472. Epub 2016 Aug 24.

Rugby League is a high-intensity collision sport competed over 80 min. Training loads are monitored to maximize recovery and assist in the design of nutritional strategies although no data are available on the total energy expenditure (TEE) of players. We therefore assessed resting metabolic rate (RMR) and TEE in six Super League players over 2 consecutive weeks in-season including one game per week. Fasted RMR was assessed followed by a baseline urine sample before oral administration of a bolus dose of hydrogen (deuterium H) and oxygen (O) stable isotopes in the form of water (HO). Every 24 hr thereafter, players provided urine for analysis of TEE via DLW method. Individual training load was quantified using session rating of perceived exertion (sRPE) and data were analyzed using magnitude-based inferences. There were unclear differences in RMR between forwards and backs (7.7 ± 0.5 cf. 8.0 ± 0.3 MJ, respectively). Indirect calorimetry produced RMR values most likely lower than predictive equations (7.9 ± 0.4 cf. 9.2 ± 0.4 MJ, respectively). A most likely increase in TEE from Week 1 to 2 was observed (17.9 ± 2.1 cf. 24.2 ± 3.4 MJ) explained by a most likelyincrease in weekly sRPE (432 ± 19 cf. 555 ± 22 AU), respectively. The difference in TEE between forward and backs was unclear (21.6 ± 4.2 cf. 20.5 ± 4.9 MJ, respectively). We report greater TEE than previously reported in rugby that could be explained by the ability of DLW to account for all match and training-related activities that contributes to TEE.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1123/ijsnem.2015-0335DOI Listing
October 2016

Surveillance of adverse events associated with local anaesthesia for cataract surgery in Australia and New Zealand.

Clin Exp Ophthalmol 2017 08 10;45(6):640-641. Epub 2016 Aug 10.

Department of Ophthalmology, Flinders University, Bedford Park, South Australia, Australia.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/ceo.12803DOI Listing
August 2017

Muscle glycogen utilisation during Rugby match play: Effects of pre-game carbohydrate.

J Sci Med Sport 2016 Dec 22;19(12):1033-1038. Epub 2016 Apr 22.

Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, UK. Electronic address:

Objectives: Although the physical demands of Rugby League (RL) match-play are well-known, the fuel sources supporting energy-production are poorly understood. We therefore assessed muscle glycogen utilisation and plasma metabolite responses to RL match-play after a relatively high (HCHO) or relatively low CHO (LCHO) diet.

Design: Sixteen (mean±SD age; 18±1 years, body-mass; 88±12kg, height 180±8cm) professional players completed a RL match after 36-h consuming a non-isocaloric high carbohydrate (n=8; 6gkgday) or low carbohydrate (n=8; 3gkgday) diet.

Methods: Muscle biopsies and blood samples were obtained pre- and post-match, alongside external and internal loads quantified using Global Positioning System technology and heart rate, respectively. Data were analysed using effects sizes ±90% CI and magnitude-based inferences.

Results: Differences in pre-match muscle glycogen between high and low carbohydrate conditions (449±51 and 444±81mmolkgd.w.) were unclear. High (243±43mmolkgd.w.) and low carbohydrate groups (298±130mmolkgd.w.) were most and very likely reduced post-match, respectively. For both groups, differences in pre-match NEFA and glycerol were unclear, with a most likely increase in NEFA and glycerol post-match. NEFA was likely lower in the high compared with low carbohydrate group post-match (0.95±0.39mmoll and 1.45±0.51mmoll, respectively), whereas differences between the 2 groups for glycerol were unclear (98.1±33.6mmoll and 123.1±39.6mmoll) in the high and low carbohydrate groups, respectively.

Conclusions: Professional RL players can utilise ∼40% of their muscle glycogen during a competitive match regardless of their carbohydrate consumption in the preceding 36-h.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jsams.2016.03.008DOI Listing
December 2016

Dynamic Knee Alignment and Collateral Knee Laxity and Its Variations in Normal Humans.

Front Surg 2015 25;2:62. Epub 2015 Nov 25.

Golden Jubilee National Hospital , Glasgow , UK ; University of Strathclyde , Glasgow , UK.

Alignment of normal, arthritic, and replaced human knees is a much debated subject as is the collateral ligamentous laxity. Traditional quantitative values have been challenged. Methods used to measure these are also not without flaws. Authors review the recent literature and a novel method of measurement of these values has been included. This method includes use of computer navigation technique in clinic setting for assessment of the normal or affected knee before the surgery. Computer navigation has been known for achievement of alignment accuracy during knee surgery. Now its use in clinic setting has added to the inventory of measurement methods. Authors dispel the common myth of straight mechanical axis in normal knees and also look at quantification of amount of collateral knee laxity. Based on the scientific studies, it has been shown that the mean alignment is in varus in normal knees. It changes from lying non-weight-bearing position to standing weight-bearing position in both coronal and the sagittal planes. It also varies with gender and race. The collateral laxity is also different for males and females. Further studies are needed to define the ideal alignment and collateral laxity which the surgeon should aim for individual knees.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fsurg.2015.00062DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4658436PMC
December 2015

Establishing the plane of symmetry for lumen formation and bilateral brain formation in the zebrafish neural rod.

Semin Cell Dev Biol 2014 Jul 8;31:100-5. Epub 2014 Apr 8.

MRC Centre for Developmental Neurobiology, King's College London, London SE1 1UL, UK. Electronic address:

The lumen of the zebrafish neural tube develops precisely at the midline of the solid neural rod primordium. This process depends on cell polarisation and cell rearrangements, both of which are manifest at the midline of the neural rod. The result of this cell polarisation and cell rearrangement is an epithelial tube that has overt mirror-symmetry, such that cell morphology and apicobasal polarisation are mirrored across the midline of the neural tube. This article discusses how this mirror-symmetry is established and proposes the hypothesis that positioning the cells' centrosomes to the midline of the neural rod is a key event in organising this process.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.semcdb.2014.04.008DOI Listing
July 2014

Optimal hyaluronidase dosage.

Authors:
Jon Clarke

Clin Exp Ophthalmol 2014 Apr 4;42(3):299. Epub 2013 Aug 4.

Anaesthesia, Flinders Medical Centre, Adelaide, South Australia, Australia.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/ceo.12171DOI Listing
April 2014

Standardising the clinical assessment of coronal knee laxity.

Proc Inst Mech Eng H 2012 Sep;226(9):699-708

Department of Orthopaedics, Golden jubilee National Hospital, UK.

Clinical laxity tests are used for assessing knee ligament injuries and for soft tissue balancing in total knee arthroplasty. This study reports the development and validation of a quantitative technique of assessing collateral knee laxity through accurate measurement of potential variables during routine clinical examination. The hypothesis was that standardisation of a clinical stress test would result in a repeatable range of laxity measurements. Non-invasive infrared tracking technology with kinematic registration of joint centres gave real-time measurement of both coronal and sagittal mechanical tibiofemoral alignment Knee flexion, moment arm and magnitude of the applied force were all measured and standardised. Three clinicians then performed six knee laxity examinations on a single volunteer using a target moment of 18 Nm. Standardised laxity measurements had small standard deviations (within 1. 1 degree) for each clinician and similar mean values between clinicians, with the valgus laxity assessment (mean of 3 degrees) being slightly more consistent than varus (means of 4 degrees or 5 degrees). The manual technique of coronal knee laxity assessment was successfully quantified and standardised, leading to a narrow range of measurements (within the accuracy of the measurement system). Minimising the subjective variables of clinical examination could improve current knowledge of soft tissue knee behaviour.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1177/0954411912451814DOI Listing
September 2012
-->