Geometric deep learning is a relatively new field that combines the principles of deep learning with techniques from geometry and topology to analyze data with complex structures, such as graphs and manifolds. In orthopedic research, geometric deep learning has been applied to a variety of tasks, including the analysis of imaging data to detect and classify abnormalities, the prediction of patient outcomes following surgical interventions, and the identification of risk factors for degenerative joint disease. This review aims to summarize the current state of the field and highlight the key findings and applications of geometric deep learning in orthopedic research. The review also discusses the potential benefits and limitations of these approaches and identifies areas for future research. Overall, the use of geometric deep learning in orthopedic research has the potential to greatly advance our understanding of the musculoskeletal system and improve patient care

Spinal surgery deals with the treatment of different pathological conditions of the spine such as tumors, deformities, degenerative disease, infections and traumas. Research in the field of vertebral surgery can be divided into two main areas: 1) research lines transversal to the different branches; 2) specific research lines for the different branches. The transversal lines of research are represented by strategies for the reduction of complications, by the development of minimally invasive surgical techniques, by the development of surgical navigation systems and by the development of increasingly reliable systems for the control of intra-operative monitoring. Instead, specific lines of research are developed within the different branches. In the field of oncological pathology, the current research concerns the development of in vitro models for the study of metastases and research for the study of targeted treatment methods such as electrochemotherapy and mesenchymal stem cells for the treatment of aneurysmal bone cysts. Research in the field of spinal deformities is focused on the development of increasingly minimally invasive methods and systems which, combined with appropriate pharmacological treatments, help reduce trauma, stress and post-operative pain. Scaffolds based on blood clots are also being developed to promote vertebral fusion, a fundamental requirement for improving the outcome of vertebral arthrodesis performed for the treatment of degenerative disc disease. To improve the management and the medical and surgical treatment of vertebral infections, research has focused on the definition of multidisciplinary strategies aimed at identifying the best possible treatment path. Thus, flow-charts have been created which allow to manage the patient suffering from vertebral infection. In addition, dedicated silver-coated surgical instrumentation and bone substitutes have been developed that simultaneously guarantee mechanical stability and reduce the risk of further local infection. In the field of vertebral traumatology, the most recent research studies have focused on the development of methods for the biostimulation of the bone growth in order to obtain, when possible, healing without surgery. Methods have also been developed that allow the minimally invasive percutaneous treatment of fractures by means of vertebral augmentation with PMMA, or more recently with the use of silicone which from a biomechanical point of view has an elastic modulus more similar to that of bone. It is clear that scientific research has changed clinical practice both in terms of medical and surgical management of patients with spinal pathologies. The results obtained stimulate the basic research to achieve even more. For this reason, new lines of research have been undertaken which, in the oncology field, aim at developing increasingly specific therapies against target receptors. Research efforts are also being multiplied to achieve regeneration of the degenerated intervertebral disc and to develop implants with characteristics increasingly similar to those of bone in order to improve mechanical stability and durability over time. Photodynamic therapies are being developed for the treatment of infections in order to reduce the use of antibiotic therapies. Finally, innovative lines of research are being launched to treat and regenerate damaged nerve structures with the goal, still far from today, of making patients with spinal cord injuries to walk

To create a comprehensive, user-friendly, database that facilitates selection of optimized animal models for fracture research. Preclinical testing using research animal models can expedite effective and safe interventions for clinical fracture patients but ethical considerations (e.g., adherence to 3R humane principles) and failure to meet critical review (e.g., clinical translation, reproducibility) currently complicate the model selection process. English language publications (1980-2021) were derived from PubMed® using the search-term ‘bone and fracture and animal’. Clinical cases, reviews, and cadaver studies were excluded. Qualifying papers reporting use of fracture models had the following data transcribed: Author, journal, abstract, summary data, animal data, bone, focus (e.g., allograft) and model (e.g., articular fracture). Publications were quantitatively scored (1 star [very poor] – 5 stars [excellent]) for reproducibility, clinical translation and animal welfare. 4602 papers were derived from 677 journals from 177 publishers. Number of annual publications progressively increased from 18 (1980), peaking in 2015 (250) before substantially declining in 2020 (121) and 2021 (51). Descriptors (low to high) included 15 species (frog [1]–rat [1586]), 24 bones (phalanx [1]–femur [1646]), 134 research foci (bioprinting [4]–fracture healing [3533]), and 37 fracture models (avulsion [4]–diaphyseal [2113]). Percent of total publications scoring 1 or more stars for reproducibility, clinical translation and animal welfare ranged from: 1.0–5.8% (1 star), 5.9–30.6% (2 star), 21.3–42.8% (3 star), 19.2–44.4% (4 stars), and 1.3–26.7% (5 stars). FRAMD provides a dedicated resource that enhances selection of animal models that pertain to researchers’ fracture focus while being clinically relevant, reproducible and humane. FRAMD will help improve scientific data, reduce unnecessary use of animals, heighten workplace efficiency, and reduce cost by avoiding ill-suited or outdated models. FRAMD may particularly benefit grant writers and organizations seeking ‘best-practice’ assurance (e.g., funding agencies, academic research societies, CROs)

Non-linear methods in statistical shape analysis have become increasingly important in orthopedic research as they allow for more accurate and robust analysis of complex shape data such as articulated joints, bony defects and cartilage loss. These methods involve the use of non-linear transformations to describe shapes, rather than the traditional linear approaches, and have been shown to improve the precision and sensitivity of shape analysis in a variety of applications. In orthopedic research, non-linear methods have been used to study a range of topics, including the analysis of bone shape and structure in relation to osteoarthritis, the assessment of joint deformities and their impact on joint function, and the prediction of patient outcomes following surgical interventions. Overall, the use of non-linear methods in statistical shape analysis has the potential to advance our understanding of the relationship between shape and function in the musculoskeletal system and improve the diagnosis and treatment of orthopedic conditions

There has been a recent surge in the creation of medical student-led and foundation trainees-led research collaboratives in surgery. These have mainly been in general surgery. The current study therefore explores the value and feasibility of such collaboratives, highlighting the scope for a similar idea in orthopaedics. Research Collaborative organisations were systematically searched and reviewed to check whether medical students or junior doctors prior to speciality training led them. The advertised research projects and subsequent publication productivity for each identified organisation was also evaluated using the information presented on their websites. Two medical student-led research collaborative organisations and 1 medical student and foundation trainees-led research collaborative were identified. All of which are in general surgery and none in trauma and/or orthopaedics surgery. These include STARSurg, EuroSurg and GlobalSurg respectively. A total of 6 research collaborative projects were identified with 3 leading to subsequent publications. This study highlights the value and feasibility of medical students- and foundation trainees-driven high quality surgical research collaborative. It also emphasises the growing contribution of medical students towards research and policymaking in our global health system, an aspect that may be absent or delayed in the field of orthopaedics. We therefore, explore the idea as well as the need to instigate a similar collaboration in the field of trauma and orthopaedic surgery

Background. In Japan, idiopathic osteonecrosis of the femoral head (ONFH) is designated as a specified rare and intractable disease in patients for whom medical care is subsidized through the Specified Disease Treatment Research Program. Each patient is approved for the subsidy based upon a prefectural governmental review after filing an application together with a clinical research form documenting the patient's medical history, laboratory/clinical findings, and treatment. The purpose of this study was to conduct a fact-finding study of ONFH patients in the Fukuoka Prefecture based on clinical research forms of the Specified Disease Treatment Research Program. Methods. The distribution by gender and age of ONFH patients who filed an application for subsidy under this program between 1999 and 2008 was investigated on the basis of clinical research forms in the Fukuoka Prefecture. For comparative purposes, we also investigated the distribution by gender and age of ONFH patients who had a final diagnosis of ONFH at our institution during the past three years. Results. In the Fukuoka Prefecture, 1,244 ONFH patients (758 men, 61%; and 486 women, 39%) were identified during the 10-year period. The mean age was 48 years for men and 56 years for women. Men showed a normal age distribution with a peak in their fifties, whereas, women displayed a bimodal distribution with peaks in their fifties and seventies. The numbers of patients aged greater than 60 years were 162 (21.4%) for men and 218 (44.9%) for women. At our institution, there were 94 patients (61 men, 64.9%; and 33 women, 35.1%) who had a final diagnosis of ONFH based on radiology and pathology during the 3-year period. The mean age of these patients was 44 years for mrn and 45 years for women. Men showed a bimodal distribution with peaks in their thirties and fifties, whereas, women displayed a unimodal distribution with a peak in their fifties. The numbers of patients aged greater than 60 years were 7 (11.5%) for men and 6 (18.2%) for women. The age distribution of ONFH patients in the Fukuoka Prefecture was significantly higher, particularly for women, compared with patients at our institution. Conclusion. The present study, based on clinical research forms showed that 1,244 patients were identified as having ONFH in the Fukuoka Prefecture during a 10-year period, with a men-to-women ratio of 6:4. For women, approximately half were aged greater than 60 years of age

For decades, universities and research centers have been applying modeling and simulation (M&S) to problems involving health and medicine, coining the expression in silico clinical trials. However, its use is still limited to a restricted pool of specialists. It is here proposed an easy-to-use cloud-based platform that aims to create a collaborative marketplace for M&S in orthopedics, where developers and model creators are able to capitalize on their work while protecting their intellectual property (IP), and researcher, surgeons and medical device companies can use M&S to accelerate time and to reduce costs of their research and development (R&D) processes. Digital libraries on . InSilicoTrials.com. are built on collaborations among first-rate research center, model developers, software, and cloud providers (partners). Their access is provided to life science and healthcare companies, clinical centers, and research institutes (users), offering them with several solutions for the different steps of the orthopedics and medical devices R&D process. The platform is built using the Microsoft Azure cloud services, conforming to global standards of security and privacy for healthcare, ensuring that clinical data is properly managed, protected, and kept private. The environment protects the IP of partners against the downloading, copying, and changing of their M&S solutions; while providing a safe environment for users to seamlessly upload their own data, set up and run simulations, analyze results, and produce reports in conformity with regulatory requirements. The proposed platform allows exploitation of M&S through a Software-as-a-Service delivery model. The pay-per-use pricing: 1. provide partners with a strong incentive to commercialize their high-quality M&S solutions; 2. enable users with limited budget, such as small companies, research centers and hospitals, to use advanced M&S solutions. Pricing of the M&S tools is based on specific aspects, such as particular features and computational power required, in agreement with the developing partner, and is distinct for different types of customers (i.e., academia or industry). The first medical devices application hosted on . InSilicoTrials.com. is NuMRis (Numerical Magnetic Resonance Implant Safety), implemented in collaboration with the U.S. F.D.A. Center for Devices and Radiological Health, and ANSYS, Inc. The automatic tool allows the investigation of radiofrequency (RF)-induced heating of passive medical implants, such as orthopedic devices (e.g., rods and screws), pain management devices (e.g., leads), and cardiovascular devices (e.g., stents), following the ASTM F2182-19e2 Standard Test Method. NuMRis promotes the broader adoption of digital evidence in preclinical trials for RF safety analysis, supporting the device submission process and pre-market regulatory evaluation. InSilicoTrials.com. aims at defining a new collaborative framework in healthcare, engaging research centers to safely commercialize their IP, i.e., model templates, simulation tools and virtual patients, by helping clinicians and healthcare companies to significantly expedite the pre-clinical and clinical development phases, and to move across the regulatory approval and HTA processes

The widespread dissemination of high-quality research facilitates keeping up to date with evidence-based practice, but the vast quantity can be overwhelming to physicians and surgeons. Information graphics, abbreviated to infographics, convey information using visualisations and images in an engaging manner. This format of presenting research format is preferable to 80% of clinicians when compared to text articles, and the long-term retention of information has been shown to be improve by a factor of 6.5 when methods were compared. Journal club was audited in our institution over 3 months. A multi-choice questionnaire was constructed weekly so as to test the attendees' recall of the research presented on a weekly basis. After five weeks, infographics were introduced, and the attendees' recall was assessed again on a weekly basis at the end of each journal club. The introduction of infographics to journal club saw improved test results from the journal club attendees. Not only was information retention improved, but the duration of journal club reduced following the intervention. Research can be disseminated efficiently using infographics in place of conventional journal club presentations. Satisfaction rates among clinicians, both with information retention and journal club duration, demonstrate the benefit of their use in teaching hospitals

We need to shift our focus to integrating sex and gender into research proposals, so we can answer some of the most basic unanswered questions in the field of fracture management. Current evidence in guidelines indicate a near-to-linear increase from the 1990s for inclusion of sex and gender. However, these recommendations remain expressed in absolute terms, with little explanatory power, affecting uptake and implementation in clinical practice. This co-branded session, with members of the Orthopaedic Research Society – International section of fracture repair (ORS-ISFR), will provide participants with guiding principles and tools to assist researchers and grant reviewers understand what it means to include sex and gender in meaningful ways: from formulating research questions, recruitment strategies, to conducting sex-stratified analyses. In this presentation, we will consider diverse approaches, methods and, analyses to elevate sex and gender within trauma. A strong emphasis on the ways and means of including marginalized and vulnerable populations in research will be addressed

In March 2020, COVID-19 was declared a pandemic by the World Health Organization. The pandemic imposed drastic changes in our social and professional routine. Professionally at all levels our hospital tasks were changed and prioritized. Surgeons and residents were deployed on rotations to fields other than their expertise in orthopaedics. Health-care education received major changes in these challenging times, and students did face difficulties in receiving education, as well as training due to limited clinical and surgical exposure.

In response to the WHO regulations, most of the teaching centres and hospitals worldwide have adopted the web-based teaching and learning model to continue the education and training of orthopaedic residents. These results brought significant changes to the training experience in orthopaedic surgery in combination with the fact that clinical duty hours and case volume were substantially reduced.

In what concerns orthopaedic journal publications, the Covid-19 pandemic resulted in a decline in the annual publication rate for the first time in over 20 years. Although not uniform, the reduction was most likely due to multifactorial causes.

Regarding the appraisal at the end of training, at the Orthopaedic European Board Examination we were able to verify that the outcome at the written part 1 exam was good, equivalent to the outcome prior to the pandemic. However the oral viva was much worse, probably due to the fact that residents skipped much of the clinical and surgical teaching and exposure during 2020 and 2021. At the end of training, theoretical/factual knowledge was good but poor from the clinical practical experience.

Trauma and orthopaedics is the largest of the surgical specialties and yet attracts a disproportionately small fraction of available national and international funding for health research. With the burden of musculoskeletal disease increasing, high-quality research is required to improve the evidence base for orthopaedic practice. Using the current research landscape in the United Kingdom as an example, but also addressing the international perspective, we highlight the issues surrounding poor levels of research funding in trauma and orthopaedics and indicate avenues for improving the impact and success of surgical musculoskeletal research. Cite this article: Bone Joint J 2014; 96-B:1578–85

Scientific truth is an oxymoron. The goal of modern science is an understanding of the natural world. Truth is the goal of empiricism. In orthopaedic research conflict develops between these goals because empiricists seek to discover ways to improve musculoskeletal health and scientists seek to understand how the musculoskeletal system functions. When resources are limited, a hard choice must be made concerning which path to pursue. The conflict actually has a long history in Western culture that can be traced to differences between Greek and Roman approaches to discovering truths about the natural world. For ancient Greeks, no truth was complete unless a cause-and-effect connection could be established following analysis of observations. For Romans, truths were empirical. They were solutions to solved problems; an aqueduct that did not leak or a healed fracture. Empirical approaches to problems have been a characteristic of Homo sapiens since the Stone Age. They defined the original methodology of medicine and so established it as a “truth” profession. The Romans added engineering to the list of truth professions, although they did not classify it as a profession. Engineering and medicine functioned as truth professions until the 20th century. Science was much slower to mature. The term “scientist” was not coined until 1834. It was not established as a distinct profession until it was freed from scholasticism by the natural philosopher, Francis Bacon, who introduced inductive logic, and Galileo Galilei in the 17th century. They and Isaac Newton launched the Enlightenment which stimulated scientific research for over a century. By the mid-19. th. century, progress in science was sufficient to convince many scientists that they were members of a truth profession that would eventually be able to explain all life functions in terms of physics and chemistry. This reductionist view prevailed until 1927, when it was shown to be invalid by Werner Heisenberg. As a consequence of his ‘Principle of Uncertainty’, science is no longer a “truth” profession. Instead, scientific analysis has become a statistical methodology devoid of final proofs. In place of proofs, the scientist must formulate falsifiable hypotheses that are the reverse of those being proposed. In this approach, developed mainly by Karl Popper, observations are analyzed statistically and if they significantly disagree with the falsifiable hypothesis it may be said to have been disproven and one can say that the data support the proposed hypothesis. Members of truth professions began to perform experiments and employ science as an approach to truth in the 20th century thereby developing an “empirical science”. Since these investigators are constrained by their profession to favor truths, they tend to minimize the Greek and maximize the Roman components of their research. The result has been a dichotomy in science between those whose research success is measured by its contribution to “cures” and those whose research success is measured by its contribution to understanding. In orthopaedics, the dichotomy separates analytical scientists from engineers and physicians. In addition, caught in between are the bioengineers. There is a need for better communication between all

Background. The economic crisis has significantly altered the quality of life in Greece. The obvious negative impact on the offered social and health services has been adequately analysed. We aimed to determine whether the economic crisis has influenced the quantity and quality of Orthopaedic research in Greece, as mirrored from the papers presented at the annual meetings of Hellenic Association of Orthopaedic Surgery between the years 2008–2014. Methods. The abstracts of the papers (oral and posters) presented in these meetings have been examined. Details regarding the department of origin were registered. We determined the level of evidence (according to the AAOS classification system), found the amount of papers that were published in PubMed journal and noted if a department of another country participated. Results. Through the years 2008–2014 the papers concerning clinical and basic orthopaedic research that were presented were 146, 207, 304, 331, 318, 234 and 191 respectively. The percentage of those that were level 1 studies was approximately 2%, 3%, 2%, 3%, 2%, 4% and 4% respectively. The percentage of level 2 studies was 2%, 1%, 2%, 3%, 1%, 3% and 0%. Level 3 studies were the 10%, 9%, 7%, 7%, 7%, 9% and 6%. The percentage of level 4 studies was 75%, 74%, 60%, 59%, 61%, 65% and 64%. Level 5 studies were the 10%, 17%, 31%, 27%, 28%, 19% and 26%. Each year, the papers that were published in PubMed were 7%, 21%, 13%, 7%, 6%, 6% and 9%. A department of another country participated in 18%, 17%, 18%, 16%, 16%, 21% and 13% of the total of papers. Conclusion. As the economic crisis deepens, the quantity of the presented papers has been reduced. More importantly, the percentage of level 1 and 2 studies has been remained steadily low. Also, we could remark a reduction on the published studies in PubMed journals. These results raise concerns about the potential impact of the crisis in the future. Level of Evidence. IV

Artificial bone models (ABMs) are commonly used in traumatology and orthopedics for training, education, research and development purposes. The aim of this study was to develop the first evidence-based generic Asian pelvic bone model and compare it to an existing pelvic model. A hundred clinical CT scans of intact adult pelvises (54.8±16.4 years, 161.3±8.3 cm) were acquired. They represented evenly distributed female and male patients of Malay (n=33), Chinese (n=34) and Indian (n=33) descent. The CTs were segmented and defined landmarks were placed. By this means, 100 individual three-dimensional models were calculated using thin plate spline transformation. Following, three statistical mean pelvic models (male, female, unisex) were generated. Anatomical variations were analyzed using principal component analysis (PCA). To quantify length variations, the distances between the anterior superior iliac spines (ASIS), the anterior inferior iliac spines (AIIS), the promontory and symphysis (conjugate vera) as well as the ischial spines (diameter transversa) were measured for the three mean models and the existing ABM. PCA demonstrated large variability regarding pelvic surface and size. Principal component one (PC 1) contributed to 24% of the total anatomical variation and predominantly displayed a size variation pattern. PC 2 (17.7% of variation) mainly exhibited anatomical variations originating from differences in shape. Female and male models were similar in ASIS (225±20 mm; 227±13 mm) and AIIS (185±11 mm; 187±10 mm), whereas differed in conjugate vera (116±10 mm; 105±10 mm) and diameter transversa (105±7 mm; 88±8 mm). Comparing the Asian unisex model to the existing ABM, the external pelvic measurements ASIS (22.6 cm; 27.5 cm) and AIIS (186 mm; 209 mm) differed notably. Conjugate vera (111 mm; 105 mm) and diameter transversa (97 mm; 95 mm) were similar in both models. Low variability of mean distances (3.78±1.7 mm) was found beyond a sample number of 30 CTs. Our analysis revealed notable anatomical variations regarding size dominating over shape and gender-specific variability. Dimensions of the generated mean models were comparatively smaller compared to the existing ABM. This highlights the necessity for generation of Asian ABMs by evidence-based modeling techniques

You have a great research question or an idea for an innovation that will change your field. You have worked tirelessly to develop the project and are excited with the outcome. Now it is time to disseminate your findings to the world. This talk will give some insight into how to maximise the impact of your writing to reach the largest possible audience. It will discuss what makes a great paper, and provide pointers for navigating the editorial process, from your initial interactions with the editor to handling the sometimes-difficult process of peer review

While the phenomena of bone adaption to mechanical loading has been long observed, the mechanisms governing bone mechanotransduction during health and disease are not well understood. Our multidisciplinary experimental and computational research strives to enhance understanding of bone mechanobiology, and in particular how this process is affected at the onset of osteoporosis. We have provided an enhanced understanding of bone cell mechanosensation. We have characterised the local mechanical environment of MSCs, osteoblasts and osteocytes in vivo. Most importantly, we have discovered that the matrix composition, expression of mechanosensors and the mechanical environment of osteocytes is altered during osteoporosis. Interestingly, a mechanobiological response restores the homeostatic mechanical environment of the cells in the longer term. Our recent in vitro studies have revealed that estrogen withdrawal from bone cells alters calcium signalling, mineralisation, biochemical responses and osteogenic gene expression when these cells are exposed to an applied fluid shear stress. Our ongoing research is investigating mechanobiology-based therapeutic approaches for treatment of bone pathologies, by (1) targeting mechanoregulatory signalling pathways and (2) developing in vitro tissue regeneration strategies that seek to optimise the mechanical environment (through matrix stiffness, bioreactors) to stimulate osteogenesis

The Purpose and background to Study. The purpose of the study is to develop a new and more effective approach to the management of the return to work process in employees troubled by musculoskeletal symptoms. For the last decade, secondary prevention of persistent pain and unnecessary disability has been identified as a major challenge. The importance in particular of psychosocial obstacles to recovery been recognised (Hopkinkon Conferemce, 2005) and stimulated the Decade of the Flags Think-Tank and Conference at Keele University in 2007, where clinical, occupational and wider contextual factors were explored leading to a number of publications on clinical Yellow Flags (Nicholas et al, 2011) and occupational Blue flags (primarily perceptions of work (Shaw et al.,2009) and organisational factors (Main et al, 2013), the conclusions and recommendations from which are the subject of this abstract. Methods and results. There are insufficient workplace-focused RCTs, systematic reviews or meta-analyses from which to develop an evidence-based intervention strategy and narrative review of the clinical and organisation literature into the management of work disability and return-to-work was undertaken of research. The review considers evidence of the efficacy of interventions for addressing absenteeism and presenteeism, distinguishing worker-centred and workplace-centred interventions, and continues with consideration of new ways in which these challenges might be addressed. Conclusion. It recommends a shift from sickness management to the enhancement of well-being, with an evaluation of new organisational research into the psychology of engagement Implications for re-integrating the injured worker into the working environment, are considered not only from a biopsychological but also from a social perspective. The presentation will conclude with consideration of issues of implementation with design of interventions using strategies such as intervention-mapping, a focus on the determinants of behaviour change and advocation of an integrated approach to the optimisation of successful and sustained return to work. No conflicts of interest. No funding obtained. I confirm that the abstract has not been previously published in whole or substantial part not has it been presented at a national meeting

Abstract

Abstract. Background. Progressive muscle ischaemia results in reduced aerobic respiration and increased anaerobic respiration, as cells attempt to survive in a hypoxic environment. Acute compartment syndrome (ACS) is a progressive form of muscle ischaemia that is a surgical emergency resulting in the production of Lactic acid by cells through anaerobic respiration. Our previous research has shown that it is possible to measure H+ ions concentration (pH) as a measure of progressive muscle ischaemia (in vivo) and hypoxia (in vitro). Our aim was to correlate intramuscular pH readings and cell viability techniques with the intramuscular concentration of key metabolic biomarkers [adenosine triphosphate (ATP), Phosphocreatine (PCr), lactate and pyruvate], to assess overall cell health in a hypoxic tissue model. Methods. Nine euthanised Wistar rats were used in a non-circulatory model. A pH catheter was used to measure real-time pH levels from one of the exposed gluteus medius muscles, while muscle biopsies were taken from the contralateral gluteus medius at the start of the experiment and subsequently at every 0.1 of a pH unit decline. The metabolic biomarkers were extracted from the snap frozen muscle biopsies and analyzed with standard fluorimetric method. Another set of biopsies were stained with Hoechst 33342, Ethidium homodimer-1 and Calcein am and imaged with a Zeiss LSM880 confocal microscope. Results. Our study shows that the direct pH electrode readings decrease with time and took an average of 69 minutes to drop to a pH of 6.0. The concentrations of ATP, pyruvate and PCr declined over time, and the concentration of lactate increased over time. At pH 6.0, both ATP and PCr concentrations had decreased by 20% and pyruvate has decreased by 50%, whereas lactate had increased 6-fold. The majority of cells were still viable at a pH of 6.0, suggesting that skeletal muscle cells are remarkably robust to hypoxic insult, although this was a hypoxic model where reperfusion was not possible. Conclusions. Our research suggests that histologically, skeletal muscle cells are remarkably robust to hypoxic insult despite the reduction in the total adenine nucleotide pool, but this may not reflect the full extent of cell injury and quite possibly irreversible injury. The timely restoration of blood flow in theory should halt the hypoxic insult, but late reperfusion results in cellular dysfunction and cell death due to localised free radical formation. Further research investigating the effects of reperfusion in vivo are warranted, as this may identify an optimal time for using pharmacological agents to limit reperfusion injury, around the time of fasciotomy to treat acute compartment syndrome. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Abstract. Objectives. Acute compartment syndrome (ACS) is a progressive form of muscle ischaemia that is a surgical emergency and can have detrimental outcomes for patients if not treated optimally. The current problem is that there is no clear diagnostic threshold for ACS or guidance as to when fasciotomies should be performed. A new diagnostic method(s) is necessary to provide real-time information about the extent of muscle ischaemia in ACS. Given that lactic acid is produced by cells through anaerobic respiration, it may be possible to measure H+ ion concentration and to use this as a measure of ischaemia within muscle. Although we are familiar with the key biochemical metabolites involved in ischaemia; and the use of viability dyes in cell culture to distinguish between living or dead cells is well recognised; research has not been undertaken to correlate the biochemical and histological findings of ischaemia in skeletal muscle biopsies. Our primary aim was to investigate the potential for viability dyes to be used on live skeletal muscle biopsies (explants). Our secondary aim was to correlate the intramuscular pH readings with muscle biopsy viability. Methods. Nine euthanised Wistar rats were used. A pH catheter was inserted into one exposed gluteus medius muscles to record real-time pH levels and muscle biopsies were taken from the contralateral gluteus medius at the start of experiment and subsequently at every 0.1 of pH unit drop. Prior to muscle biopsy, the surface of the gluteus medius was painted with a layer of 50µmol/l Brilliant blue FCF solution to facilitate biopsy orientation. A 4mm punch biopsy tool was used to take biopsies. Each muscle biopsy was placed in a base mould filled with 4% ultra-low melting point agarose. The agarose embedded tissue block was sectioned to generate 400 micron thick tissue slices with a vibratome. The tissue slices were then placed in the staining solution with Hoechst 33342, Ethidium homodimer-1 and Calcein am. The tissue slices were imaged with Zeiss LSM880 confocal microscope's Z stack function. A dead muscle control was created by adding TritonX-100 to other tissue slices. For quantitative analyses, the images were analysed in Image J using the selection tool. This permitted individual cells to be identified and the mean grey value of each channel to be defined. Using the dead control, we were able to identify the threshold value for living cells using the Calcein AM channel. Results. Viability dyes, used primarily for cell cultures, can be used with skeletal muscle explants. Our study also showed that despite a significant reduction in tissue pH concentration over time, that almost 100% of muscle cells were still viable at pH 6.0, suggesting that skeletal muscle cells are robust to hypoxic insult in the absence of reperfusion. Conclusions. Viability dyes can be used on skeletal muscle biopsies. Further research investigating the likely associations between direct measured pH using a pH catheter, the concentrations of key cellular metabolic markers, and muscle tissue histology using vitality dyes in response to ischaemia, rather than hypoxia, is warranted. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project