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Journal articleHolman A, Clunie G, Roe J, et al., 2018,
Management of swallowing in adults undergoing laryngotracheal resection and reconstruction
, Perspectives of the ASHA Special Interest Groups, Vol: 3, Pages: 113-123, ISSN: 2381-4764Purpose: This article presents a detailed review of the etiology of laryngotracheal stenosis, common surgical procedures, and typical pathophysiological changes affecting swallowing function. We describe the redundancy in airway protection and the possibility of safe swallowing in suboptimal conditions.Conclusion: Comprehensive understanding of unique patient factors and swallowing physiology in this complex population facilitates targeted and patient-specific rehabilitation.
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Journal articleJones GG, Logishetty K, Clarke S, et al., 2018,
Do patient-specific instruments (PSI) for UKA allow non-expert surgeons to achieve the same saw cut accuracy as expert surgeons?
, Archives of Orthopaedic and Trauma Surgery, Vol: 138, Pages: 1601-1608, ISSN: 0936-8051INTRODUCTION: High-volume unicompartmental knee arthroplasty (UKA) surgeons have lower revision rates, in part due to improved intra-operative component alignment. This study set out to determine whether PSI might allow non-expert surgeons to achieve the same level of accuracy as expert surgeons. MATERIALS AND METHODS: Thirty-four surgical trainees with no prior experience of UKA, and four high-volume UKA surgeons were asked to perform the tibial saw cuts for a medial UKA in a sawbone model using both conventional and patient-specific instrumentation (PSI) with the aim of achieving a specified pre-operative plan. Half the participants in each group started with conventional instrumentation, and half with PSI. CT scans of the 76 cut sawbones were then segmented and reliably orientated in space, before saw cut position in the sagittal, coronal and axial planes was measured, and compared to the pre-operative plan. RESULTS: The compound error (absolute error in the coronal, sagittal and axial planes combined) for experts using conventional instruments was significantly less than that of the trainees (11.6°±4.0° v 7.7° ±2.3º, p = 0.029). PSI improved trainee accuracy to the same level as experts using conventional instruments (compound error 5.5° ±3.4º v 7.7° ±2.3º, p = 0.396) and patient-specific instruments (compound error 5.5° ±3.4º v 7.3° ±4.1º, p = 0.3). PSI did not improve the accuracy of high-volume surgeons (p = 0.3). CONCLUSIONS: In a sawbone model, PSI allowed inexperienced surgeons to achieve more accurate saw cuts, equivalent to expert surgeons, and thus has the potential to reduce revision rates. The next test will be to determine whether these results can be replicated in a clinical trial.
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Conference paperMa S, Goh EL, Karunaratne A, et al., 2018,
The Effects of Bisphosphonate at the Nanoscale: Effects on Bone Collagen, Mineral Strain and Collagen-Mineral Interaction
, Annual Meeting of the American-Society-for-Bone-and-Mineral-Research, Publisher: WILEY, Pages: 410-411, ISSN: 0884-0431 -
Journal articleRivière C, Dhaif F, Shah H, et al., 2018,
Kinematic alignment of current TKA implants does not restore the native trochlear anatomy
, Revue de Chirurgie Orthopedique et Traumatologique, Vol: 104, Pages: 673-685, ISSN: 1877-0517 -
Journal articleRivière C, Dhaif F, Shah H, et al., 2018,
Kinematic alignment of current TKA implants does not restore the native trochlear anatomy
, Orthopaedics and Traumatology: Surgery and Research, Vol: 104, Pages: 983-995, ISSN: 1877-0568INTRODUCTION: Preserving constitutional patellofemoral anatomy, and thus producing physiological patellofemoral kinematics, could prevent patellofemoral complications and improve clinical outcomes after kinematically aligned TKA (KA TKA). Our study aims 1) to compare the native and prosthetic trochleae (planned or implanted), and 2) to estimate the safety of implanting a larger Persona® femoral component size matching the proximal lateral trochlea facet height (flange area) in order to reduce the native articular surfaces understuffing generated by the prosthetic KA trochlea. METHODS: Persona® femoral component 3D model was virtually kinematically aligned on 3D bone-cartilage models of healthy knees by using a conventional KA technique (group 1, 36 models, planned KA TKA) or an alternative KA technique (AT KA TKA) aiming to match the proximal (flange area) lateral facet height (10 models, planned AT KA TKA). Also, 13 postoperative bone-implant (KA Persona®) models were co-registered to the same coordinate geometry as their preoperative bone-cartilage models (group 2 - implanted KA TKA). In-house analysis software was used to compare native and prosthetic trochlea articular surfaces and medio-lateral implant overhangs for every group. RESULTS: The planned and performed prosthetic trochleae were similar and valgus oriented (6.1° and 8.5°, respectively), substantially proximally understuffed compared to the native trochlea. The AT KA TKAs shows a high rate of native trochlea surface overstuffing (70%, 90%, and 100% for lateral facet, groove, medial facet) and mediolateral implant overhang (60%). There was no overstuffing with conventional KA TKAs having their anterior femoral cut flush. CONCLUSION: We found that with both the planned and implanted femoral components, the KA Persona® trochlea was more valgus oriented and understuffed compared to the native trochlear anatomy. In addition, restoring the lateral trochlea facet height by increasing t
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Journal articleAqil A, Patel S, Wiik A, et al., 2018,
Patient-specific guides improve hip arthroplasty surgical accuracy
, COMPUTER METHODS IN BIOMECHANICS AND BIOMEDICAL ENGINEERING, Vol: 21, Pages: 579-584, ISSN: 1025-5842 -
Journal articleWong JKL, McGregor AH, 2018,
Spatiotemporal gait changes in healthy pregnant women and women with pelvic girdle pain: a systematic review
, Journal of Back and Musculoskeletal Rehabilitation, Vol: 31, Pages: 821-838, ISSN: 1053-8127INTRODUCTION: Gait is affected in women with pelvic girdle pain (PGP), a musculoskeletal condition affecting 20% of pregnant women. Whilst there is evidence of spatiotemporal changes in gait during healthy pregnancy, less is known in relation to women with PGP. Appreciating gait characteristics during healthy pregnancy could inform our understanding of the role of gait in PGP. PURPOSE: The purpose of this review was to systematically analyse differences in the spatiotemporal parameters of gait in healthy pregnant women and those with PGP, and to make recommendations to improve research methods in investigating gait in PGP women. METHODS: The review was undertaken following the PRISMA guidelines. Three databases and pre-existing literature were electronically and manually searched. Study selection and data extraction were conducted by two reviewers. Quality assessment was performed using the NHLBI tool for Observational Cohort and Cross-sectional Studies. RESULTS: The search returned 2925 results. Fourteen studies were selected for data extraction. Twelve studies investigated gait in healthy pregnant women and two in PGP women. Studies employed either a cohort or cross-sectional design and used various methods to assess gait. Three, nine and two studies were high, medium and low in quality, respectively. Direct comparisons between studies were impeded due to incomparable gestational time-points investigated, in addition to variations in gait parameters and definitions used. CONCLUSION: Evidence from studies on healthy pregnant women could inform future research on PGP women, for which current evidence is scarce. We recommend the standardisation of critical factors to allow inter-study comparisons for a meta-analysis.
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Journal articleBhattacharyya R, Sugand K, Al-Obaidi B, et al., 2018,
Trauma simulation training: a randomized controlled trial -evaluating the effectiveness of the Imperial Femoral Intramedullary Nailing Cognitive Task Analysis (IFINCTA) tool
, Acta Orthopaedica, Vol: 89, Pages: 689-695, ISSN: 1745-3674Background and purpose - Cognitive task analysis (CTA) has been used extensively to train pilots and in other surgical specialties. However, the use of CTA within orthopedics is in its infancy. We evaluated the effectiveness of a novel CTA tool to improve understanding of the procedural steps in antegrade femoral intramedullary nailing. Material and methods - Design: A modified Delphi technique was used to generate a CTA from 3 expert orthopedic trauma surgeons for antegrade femoral intramedullary nailing. The written and audiovisual information was combined to describe the technical steps, decision points, and errors for each phase of this procedure Validation: A randomized double-blind controlled trial was undertaken with 22 medical students (novices) randomized into 2 equal groups. The intervention group were given the CTA tool and the control group were given a standard operative technique manual. They were assessed using the validated "Touch Surgery™" application assessment tool on femoral intramedullary nailing. Results - The pre-test scores between the two groups were similar. However, the post-test scores were statistically significantly better in the intervention group compared with the control group. The improvement (post-test median scores) in the intervention group compared with the control group was 20% for patient positioning and preparation, 21% for femoral preparation, 10% for proximal locking, and 19% for distal locking respectively (p < 0.001 for all comparisons). Interpretation - This is the first multimedia CTA tool in femoral intramedullary nailing that is easily accessible, user-friendly, and has demonstrated significant benefits in training novices over the traditional use of operative technique manuals.
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Conference paperFavier C, McGregor A, Phillips A, 2018,
Subject specific multiscale modelling of the lumbar spine
, 14th Annual Bath Biomechanics Symposium -
Journal articleJones G, Jaere M, Clarke S, et al., 2018,
A Clinical Trial Examining the Accuracy of High Tibial Osteotomy When Performed by Experts Using a Novel Patient Specific Instrument (PSI)
, SSRN -
Journal articleChoudhury A, Lambkin R, Auvinet E, et al., 2018,
P 004 - Patellofemoral arthroplasty improves gait in isolated patellofemoral arthritis, a prospective cohort gait analysis study.
, Gait Posture, Vol: 65 Suppl 1, Pages: 241-242 -
Journal articleZhao S, Arnold M, Ma S, et al., 2018,
Standardizing compression testing for measuring the stiffness of human bone
, BONE & JOINT RESEARCH, Vol: 7, Pages: 524-538, ISSN: 2046-3758 -
Journal articleZhao S, Arnold M, Ma S, et al., 2018,
Standardising compression testing for measuring the stiffness of human bone: a systematic review
, Bone and Joint Research, Vol: 7, Pages: 524-538, ISSN: 2046-3758Objectives: The ability to determine human bone stiffness is of clinical relevance in many fields, including bone quality assessment and orthopaedic prosthesis design. Stiffness can be measured using compression testing; an experimental technique commonly used to test bone specimens in vitro. This systematic review aims to determine how best to perform compression testing of human bone. Methods: A keyword search of all English language articles up until December 2017 of compression testing of bone was undertaken in Medline, Embase, PubMed and Scopus databases. Studies using bulk tissue, animal tissue, whole bone or testing techniques other than compression testing were excluded. Results: 4712 abstracts were retrieved with a total of 177 papers included in the analysis. 20 studies directly analysed the compression testing technique to improve the accuracy of the testing technique. Several influencing factors should be considered when testing bone samples in compression. These include the method of data analysis, specimen storage, specimen preparation, testing configuration and loading protocol. Conclusions: Compression testing is a widely used technique for measuring the stiffness of bone but there is a great deal of inter-study variation in experimental techniques across the literature. Based on best evidence from the literature, suggestions for bone compression testing are made in this review, though further studies are needed to help establish standardised bone testing techniques to increase the comparability and reliability of bone stiffness studies.
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Journal articleWiik AV, Brevadt M, Johal H, et al., 2018,
The loading patterns of a short femoral stem in total hip arthroplasty: gait analysis at increasing walking speeds and inclines.
, Journal of Orthopaedics and Traumatology, Vol: 19, ISSN: 1590-9921BACKGROUND: The purpose of this study was to examine the gait pattern of total hip arthroplasty (THA) patients with a new short femoral stem at different speeds and inclinations. MATERIALS AND METHODS: A total of 40 unilateral THA patients were tested on an instrumented treadmill. They comprised two groups (shorter stemmed THA n = 20, longer stemmed THA n = 20), both which had the same surgical posterior approach. The shorter femoral stemmed patients were taken from an ongoing hip trial with minimum 12 months postop. The comparative longer THR group with similar disease and severity were taken from a gait database along with a demographically similar group of healthy controls (n = 35). All subjects were tested through their entire range of gait speeds and inclines with ground reaction forces collected. Body weight scaling was applied and a symmetry index to compare the implanted hip to the contralateral normal hip. An analysis of variance with significance set at α = 0.05 was used. RESULTS: The experimental groups were matched demographically and implant groups for patient reported outcome measures and radiological disease. Both THA groups walked slower than controls, but symmetry at all intervals for all groups were not significantly different. Push-off loading was less favourable for both the shorter and longer stemmed THR groups (p < 0.05) depending on speed. CONCLUSIONS: Irrespective of femoral stem length, symmetry for ground reaction forces for both THA groups were returned to a normal range when compared to controls. However individual implant performance showed inferior (p < 0.05) push-off forces and normalised step length in both THR groups when compared to controls. LEVEL OF EVIDENCE: III.
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Journal articleLord BR, Colaco HB, Gupte CM, et al., 2018,
ACL graft compression: a method to allow reduced tunnel sizes in ACL reconstruction
, Knee Surgery, Sports Traumatology, Arthroscopy, Vol: 26, Pages: 2430-2437, ISSN: 0942-2056PURPOSE: A common problem during ACL reconstruction is asymmetry of proximal-distal graft diameter leading to tunnel upsizing and graft-tunnel mismatch. Compression downsizing provides a graft of uniform size, allowing easy passage into a smaller tunnel. The purpose of this study was to quantify the graft compression technique and its effects on graft biomechanics and stability. It was hypothesised that compression downsizing would significantly reduce cross-sectional area (CSA); that no significant changes in graft biomechanics would occur; graft fixation stability would be improved. METHOD: Sixty-eight non-irradiated peroneus longus (PL) tendons were investigated. Twenty were halved and paired into ten four-strand grafts, 20 strands were compressed by 0.5-1 mm diameter and changes in CSA recorded using an alginate mould technique. The following properties were compared with 20 control strands: cyclic strain when loaded 70-220 N for 1000 cycles; stiffness; ultimate tensile load and stress; Young's modulus. 24 PL tendons were quadrupled into grafts, 12 were compressed and all 24 were submerged in Ringer's solution at 37 °C and the CSA recorded over 12 h. Twelve compressed and 12 control quadrupled grafts were mounted in porcine femurs, placed in Ringer's solution for 12 h at 37 °C and graft displacement at the bone tunnel aperture recorded under cyclic loading. RESULTS: Mean decreases in CSA of 31% under a stress of 471 kPa and 21% under a stress of 447 kPa were observed for doubled and quadrupled grafts, respectively. Compressed grafts re-expanded by 19% over 12 h compared to 2% for controls. No significant differences were observed between compressed and control grafts in the biomechanical properties and graft stability; mean cyclic displacements were 0.3 mm for both groups. CONCLUSIONS: No detrimental biomechanical effects of graft compression on allograft PL tendons were observed. Following compression, t
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Journal articleRawson T, Sivakumaran P, Lobo R, et al., 2018,
Development of a web-based tool for undergraduate engagement in medical research; the ProjectPal experience
, BMC Medical Education, Vol: 18, ISSN: 1472-6920BackgroundWe report the development and evaluation of a web-based tool designed to facilitate student extra-curricular engagement in medical research through project matching students with academic supervisors.UK based university students were surveyed to explore their perceptions of undergraduate research, barriers and facilitators to current engagement. Following this, an online web-based intervention (www.ProjectPal.org) was developed to support access of students to research projects and supervisors. A pilot intervention was undertaken across a London-based university in January 2013 to February 2016. In March 2016, anonymised data were extracted from the prospective data log for analysis of website engagement and usage. Supervisors were surveyed to evaluate the website and student outputs.ResultsFifty-one students responded to the electronic survey. Twenty-four (47%) reported frustration at a perceived lack of opportunities to carry out extra-curricular academic projects. Major barriers to engaging in undergraduate research reported were difficulties in identifying suitable supervisors (33/51; 65%) and time pressures (36/51; 71%) associated with this. Students reported being opportunistic in their engagement with undergraduate research. Following implementation of the website, 438 students signed up to ProjectPal and the website was accessed 1357 times. Access increased on a yearly basis. Overall, 70 projects were advertised by 35 supervisors. There were 86 applications made by students for these projects. By February 2016, the 70 projects had generated 5 peer-review publications with a further 7 manuscripts under peer-review, 14 national presentations, and 1 national prize.ConclusionThe use of an online platform to promote undergraduate engagement with extra-curricular research appears to facilitate extra-curricular engagement with research. Further work to understand the impact compared to normal opportunistic practices in enhancing student engagement is now
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Journal articleBoughton OR, Ma S, Zhao S, et al., 2018,
Measuring bone stiffness using spherical indentation
, PLoS ONE, Vol: 13, ISSN: 1932-6203ObjectivesBone material properties are a major determinant of bone health in older age, both in terms of fracture risk and implant fixation, in orthopaedics and dentistry. Bone is an anisotropic and hierarchical material so its measured material properties depend upon the scale of metric used. The scale used should reflect the clinical problem, whether it is fracture risk, a whole bone problem, or implant stability, at the millimetre-scale. Indentation, an engineering technique involving pressing a hard-tipped material into another material with a known force, may be able to assess bone stiffness at the millimetre-scale (the apparent elastic modulus). We aimed to investigate whether spherical-tip indentation could reliably measure the apparent elastic modulus of human cortical bone.Materials and methodsCortical bone samples were retrieved from the femoral necks of nineteen patients undergoing total hip replacement surgery (10 females, 9 males, mean age: 69 years). The samples underwent indentation using a 1.5 mm diameter, ruby, spherical indenter tip, with sixty indentations per patient sample, across six locations on the bone surfaces, with ten repeated indentations at each of the six locations. The samples then underwent mechanical compression testing. The repeatability of indentation measurements of elastic modulus was assessed using the co-efficient of repeatability and the correlation between the bone elastic modulus measured by indentation and compression testing was analysed by least-squares regression.ResultsIn total, 1140 indentations in total were performed. Indentation was found to be repeatable for indentations performed at the same locations on the bone samples with a mean co-efficient of repeatability of 0.4 GigaPascals (GPa), confidence interval (C.I): 0.33–0.42 GPa. There was variation in the indentation modulus results between different locations on the bone samples (mean co-efficient of repeatability: 3.1 GPa, C.I: 2.2–3.90 GPa). No cle
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Conference paperFavier C, McGregor A, Phillips A, 2018,
Combined musculoskeletal and structural finite element modelling of the lumbar spine
, 8th World Congress of Biomechanics -
Journal articleWillmott H, Al-Wattar Z, Halewood C, et al., 2018,
Evaluation of different shape-memory staple configurations against crossed screws for first metatarsophalangeal joint arthrodesis: A biomechanical study
, Foot and Ankle Surgery, Vol: 24, Pages: 259-263, ISSN: 1268-7731BACKGROUND: The first metatarsophalangeal joint may be fused in order to treat arthritis or instability. The use of shape-memory staples for fixation is well recognised, but little work has been done into the optimal configuration of staples. METHODS: The structural behaviour of first metatarsophalangeal joint (MTPJ) arthrodeses using shape-memory staples or crossed screws was studied using cadaveric porcine joints. Five fixation configurations were tested: single vertical or horizontal staple, paired staples in dorsal-medial configuration (0-90° to the sagittal plane), paired staples in oblique orthogonal configuration (45-135°); or two crossed screws. Specimens were loaded in cyclical dorsiflexion for 1000 cycles. Plantar gapping and shearing were measured. Specimens were then loaded to failure. RESULTS: Cyclic testing caused more shear in the 45-135° staples than the crossed screws (1.0mm±0.5mm compared to 0.14mm±0.4mm, p<0.01). No significant difference was found in plantar gap formation. Single vertical and horizontal single staples failed at 15N and 19. CONCLUSIONS: N, respectively. Paired 0-90° staples failed at 43N±9N, significantly lower than the 45-135° staples (141N±25N; p<0.001) and crossed screws (180N±67N; p<0.001). There was no significant difference between the 45-135° staples and crossed screws. Screws failed by sudden cortical fracture; staples displayed gradual pull-out and shearing. First MTPJ arthrodeses fixed with single staples are not recommended. Arthrodeses fixed with staples at 0-90° to the sagittal plane were significantly less strong than two crossed screws. However, positioning oblique staples at 45-135° significantly improved stability, creating a construct as strong as, crossed screws. None of the constructs was strong enough for immediate weight bearing.
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Journal articleStevenson H, Parkes M, Austin L, et al., 2018,
The development of a small-scale wear test for CoCrMo specimens with human synovial fluid
, Biotribology, Vol: 14, Pages: 1-10, ISSN: 2352-5738A new test was developed to measure friction and wear of hip implant materials under reciprocating sliding conditions. The method requires a very small amount of lubricant (<3 ml) which allows testing of human synovial fluid. Friction and wear of Cobalt Chromium Molybdenum (CoCrMo) material pairs were measured for a range of model and human synovial fluid samples. The initial development of the test assessed the effect of fluid volume and bovine calf serum (BCS) concentration on friction and wear. In a second series of tests human synovial fluid (HSF) was used. The wear scar size (depth and volume) on the disc was dependent on protein content and reduced significantly for increasing BCS concentration. The results showed that fluid volumes of <1.5 ml were affected by evaporative loss effectively increasing the protein concentration resulting in anomalously lower wear. At the end of the test thick deposits were observed in and around the wear scars on the disc and ball; these were analysed by Infrared Reflection-Absorption Spectroscopy. The deposits were composed primarily of denatured proteins and similar IR spectra were obtained from the BCS and HSF tests. The analysis confirmed the importance of SF proteins in determining wear of CoCrMo couples.
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