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Objective: To elicit expert opinion and gain consensus on specific exercise intervention parameters to minimise hip bone mineral density (BMD) loss following traumatic lower limb amputation., Methods: In three Delphi rounds, statements were presented to a panel of 13 experts from six countries. Experts were identified through publications or clinical expertise. Round 1 involved participants rating their agreement with 22 exercise prescription statements regarding BMD loss post amputation using a 5-point Likert scale. Agreement was deemed as 3-4 on the scale (agree/strongly agree). Statements of <50% agreement were excluded. Round 2 repeated remaining statements alongside round 1 feedback. Round 3 allowed reflection on round 2 responses considering group findings and the chance to change or maintain the resp onse. Round 3 statements reaching ≥70% agreement were defined as consensus., Results: All 13 experts completed rounds 1, 2 and 3 (100% completion). Round 1 excluded 12 statements and added 1 statement (11 statements for rounds 2-3). Round 3 reached consensus on nine statements to guide future exercise interventions. Experts agreed that exercise interventions should be performed at least 2 days per week for a minimum of 6 months, including at least three different resistance exercises at an intensity of 8-12 repetitions. Interventions should include weight-bearing and multiplanar exercises, involve high-impact activities and be supervised initially., Conclusion: This expert Delphi process achieved consensus on nine items related to exercise prescription to minimise hip BMD loss following traumatic lower limb amputation. These recommendations should be tested in future interventional trials., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY. Published by BMJ.)

Aims: The survival of humeral hemiarthroplasties in patients with relatively intact glenoid cartilage could theoretically be extended by minimizing the associated postoperative glenoid erosion. Ceramic has gained attention as an alternative to metal as a material for hemiarthroplasties because of its superior tribological properties. The aim of this study was to assess the in vitro wear performance of ceramic and metal humeral hemiarthroplasties on natural glenoids., Methods: Intact right cadaveric shoulders from donors aged between 50 and 65 years were assigned to a ceramic group (n = 8, four male cadavers) and a metal group (n = 9, four male cadavers). A dedicated shoulder wear simulator was used to simulate daily activity by replicating the relevant joint motion and loading profiles. During testing, the joint was kept lubricated with diluted calf serum at room temperature. Each test of wear was performed for 500,000 cycles at 1.2 Hz. At intervals of 125,000 cycles, micro-CT scans of each glenoid were taken to characterize and quantify glenoid wear by calculating the change in the thickness of its articular cartilage., Results: At the completion of the wear test, the total thickness of the cartilage had significantly decreased in both the ceramic and metal groups, by 27% (p = 0.019) and 29% (p = 0.008), respectively. However, the differences between the two were not significant (p = 0.606) and the patterns of wear in the specimens were unpredictable. No significant correlation was found between cartilage wear and various factors, including age, sex, the size of the humeral head, joint mismatch, the thickness of the native cartilage, and the surface roughness (all p > 0.05)., Conclusion: Although ceramic has better tribological properties than metal, we did not find evidence that its use in hemiarthroplasty of the shoulder in patients with healthy cartilage is a better alternative than conventional metal humeral heads., Competing Interests: H. Mahmud reports funding from the Brunei UBD Chancellor’s PhD Scholarship, related to this study. D. Wang reports research consulting fees from Imperial College London, related to this study. C. H. Heinrichs and U. N. Hansen report the provision of implants by orthopaedic manufacturer Mathys Ltd Bettlach, related to this study. A. A. Amis and R. Emery report an institutional grant (paid to Imperial College London) from the Wellcome Trust to fund the project to build the shoulder wear simulator, related to this study., (© 2024 Mahmud et al.)

Social support is a key determinant of mental health across multiple populations and contexts. Little is known about social support among UK (ex-)military personnel, especially those with combat injuries following deployment to Afghanistan. This study aimed to investigate the level of perceived social support and its associations with mental health among injured and uninjured UK (ex-)military personnel. An analysis of baseline data from the Armed Services Trauma Rehabilitation Outcome (ADVANCE) prospective cohort study was performed. A representative sample of male UK combat-injured personnel was compared with a frequency-matched sample of uninjured personnel. Validated questionnaires were completed including the Multidimensional Scale of Perceived Social Support (MSPSS). MSPSS score was transformed using linear splines with a knot at ≥ 55. Multivariable logistic regression analyses examined associations between perceived social support and mental health. In total, 521 combat-injured participants (137 with amputations) and 515 uninjured participants were included. Median MSPSS score was 65 (interquartile range [IQR] 54-74). Injured and uninjured participants reported similar MSPSS scores, as did those injured with amputations, and non-amputation injured participants. For each one unit increase in MSPSS score (for scores ≥55), the odds of post-traumatic stress disorder decreased (adjusted odds ratio [AOR] 0.93, 95% confidence interval [CI] 0.91 to 0.96). No such association was found with MSPSS scores below 55 (AOR 0.99, 95% CI 0.97 to 1.01). Similar results were observed for depression and anxiety. Perceived social support may be a target for intervention within this population, irrespective of injury status., Competing Interests: Declaration of competing interest L.E.G and S.S are funded by the Armed Services Trauma Rehabilitation Outcome (ADVANCE) Charity. Key contributors to this charity are the Headley Court Charity (principal funder), HM Treasury (LIBOR Grant), Help for Heroes, Nuffield Trust for the Forces of the Crown, Forces in Mind Trust, National Lottery Community Fund, Blesma - The Limbless Veterans and the UK Ministry of DefenceMinistry of Defence. H.B is part-funded by a grant from the UK Ministry of DefenceMinistry of Defence (MoD). A.N.B is a serving member of the Royal Air Force. N.T.F is part-funded by a grant from the UK MoD and is a trustee (non-paid) of a charity supporting the health and wellbeing of military personnel, veterans and their families., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Introduction: Rehabilitation after childhood lower limb loss is complex and dependent on multiple stakeholders and environmental factors. While research with adults underscores the importance of involving prosthetic limb users and caregivers in discussions to drive innovation, children are often excluded or not effectively engaged. This protocol lays out the development and implementation protocol for an internationally applicable research toolkit which has been designed and evaluated around the essential presence of the child. Research domains span their unique prosthetic needs, quality of life, pain, and mobility., Methods and Analysis: Cohorts of children in contrasting environments were identified (Cambodia, Gaza Strip, and the UK) to provide a comprehensive global understanding of the child with lower limb loss. A literature review revealed a lack of appropriate tools for identifying paediatric prosthetic user requirements leading to the development of novel interview guides for each key stakeholder: child, caregiver, and prosthetist. The child's guide centred around enjoyment and engagement using card games and activities. A panel of experts in paediatric limb loss and mental health rigorously reviewed the guides. Guides were integrated with existing validated measures for quality of life, pain, and mobility to form a comprehensive toolkit. The toolkit was successfully piloted with 5 children, their families, and 2 prosthetists. This protocol lays out the toolkit rationale and implementation plan (Jan 2023 to Dec 2025). This work offers the opportunity for this cohort to enjoyably engage with research that seeks to radically improve prospects for all children living with limb loss. The outlined best practices ensure ethical considerations when working with vulnerable cohorts., Ethics and Dissemination: This study is approved to cover implementation at all geographical locations as well as the researcher institutions. Results will be disseminated through national and international conferences, as well as through manuscripts in leading peer-reviewed journals., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Edgar et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Background: Traumatic brain injury (TBI) is common in military campaigns and is a risk factor for dementia. A rme D Ser V ices Tr A uma and Rehabilitatio N Out C om E -TBI (ADVANCE-TBI) aims to ascertain neurological outcomes in UK military personnel with major battlefield trauma, leveraging advances in quantification of axonal breakdown markers like neurofilament light (NfL), and astroglial marker glial fibrillar acidic protein (GFAP) in blood. We aimed to describe the causes, prevalence and consequences of TBI, and its fluid biomarker associations., Methods: TBI history was ascertained in 1145 servicemen and veterans, of whom 579 had been exposed to major trauma. Functional and mental health assessments were administered, and blood samples were collected approximately 8 years postinjury, with plasma biomarkers quantified (n=1125) for NfL, GFAP, total tau, phospho-tau 181 , amyloid-β 42 and 40. Outcomes were related to neurotrauma exposure., Results: TBI was present in 16.9% (n=98) of exposed participants, with 46.9% classified as mild-probable and 53.1% classified as moderate to severe. Depression (β=1.65, 95% CI (1.33 to 2.03)), anxiety (β=1.65 (1.34 to 2.03)) and post-traumatic stress disorder (β=1.30 (1.19 to 1.41)) symptoms were more common after TBI, alongside poorer 6 minute walk distance (β=0.79 (0.74 to 0.84)) and quality of life (β=1.27 (1.19 to 1.36), all p<0.001). Plasma GFAP was 11% (95% CI 2 to 21) higher post-TBI (p=0.013), with greater concentrations in moderate-to-severe injuries (47% higher than mild-probable (95% CI 20% to 82%, p<0.001). Unemployment was more common among those with elevated GFAP levels post-TBI, showing a 1.14-fold increase (95% CI 1.03 to 1.27, p<0.001) for every doubling in GFAP concentration., Conclusions: TBI affected nearly a fifth of trauma-exposed personnel, related to worse mental health, motor and functional outcomes, as well as elevated plasma GFAP levels 8 years post-injury. This was absent after extracranial trauma, and showed a dose-response relationship with the severity of the injury., Competing Interests: Competing interests: HZ has served at scientific advisory boards and/or as a consultant for AbbVie, Acumen, Alector, Alzinova, ALZPath, Annexon, Apellis, Artery Therapeutics, AZTherapies, CogRx, Denali, Eisai, Nervgen, Novo Nordisk, Optoceutics, Passage Bio, Pinteon Therapeutics, Prothena, Red Abbey Labs, reMYND, Roche, Samumed, Siemens Healthineers, Triplet Therapeutics and Wave; has given lectures in symposia sponsored by Cellectricon, Fujirebio, Alzecure, Biogen and Roche and is a co-founder of Brain Biomarker Solutions in Gothenburg AB (BBS), which is a part of the GU Ventures Incubator Programme (outside submitted work). DS provides medicolegal services and serves on the Rugby Football Union concussion advisory board. All other authors declare no conflicts of interest., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY. Published by BMJ.)

Objective: Upper limb (UL) disability in people with UL loss is well reported in the literature, less so for people with lower limb loss. This study aimed to compare UL disability in injured (major trauma) and uninjured UK military personnel, with particular focus on people with upper and lower limb loss., Methods: A volunteer sample of injured (n = 579) and uninjured (n = 566) UK military personnel who served in a combat role in the Afghanistan war were frequency matched on age, sex, service, rank, regiment, role, and deployment period and recruited to the Armed Services Trauma Rehabilitation Outcome (ADVANCE) longitudinal cohort study. Participants completed the Disability of the Arm, Shoulder, and Hand (DASH) questionnaire, scored from 0 (no disability) to 100 (maximum disability) 8 years postinjury. Mann-Whitney U and Kruskal-Wallis tests were used to compared DASH scores between groups. An ordinal model was used to assess the effect of injury and amputation on DASH scores., Results: DASH scores were higher in the Injured group compared to the Uninjured group (3.33 vs 0.00) and higher in people with lower limb loss compared to the Uninjured group (0.83 vs 0.00), although this was not statistically significant. In the adjusted ordinal model, the odds of having a higher DASH score was 1.70 (95% CI = 1.18-2.47) times higher for people with lower limb loss compared to the Uninjured group. DASH score was not significantly different between people with major and partial UL loss (15.42 vs 12.92). The odds of having a higher DASH score was 8.30 (95% CI = 5.07-13.60) times higher for people with UL loss compared to the Uninjured group., Conclusion: People with lower limb loss have increased odds of having more UL disability than the Uninjured population 8 years postinjury. People with major and partial UL loss have similar UL disability. The ADVANCE study will continue to follow this population for the next 20 years., Impact: For the first time, potential for greater long-term UL disability has been shown in people with lower limb loss, likely resulting from daily biomechanical compensations such as weight-bearing, balance, and power generation. This population may benefit from prophylactic upper limb rehabilitation, strength, and technique., (© The Author(s) 2024. Published by Oxford University Press on behalf of the American Physical Therapy Association.)

Background: Respiration is a crucial determinant of autonomic balance and heart rate variability (HRV). The comparative effect of spontaneous versus paced breathing on HRV has been almost exclusively explored in healthy adults and never been investigated in an injured military cohort., Objective: To examine the effect of spontaneous versus paced breathing on HRV in veterans with combat-related traumatic injury (CRTI)., Design: Observational cohort study., Setting: ArmeD serVices trAuma rehabilitatioN outComE (ADVANCE) study, Stanford Hall, UK., Participants: The sample consisted of 100 randomly selected participants who sustained CRTI (eg, amputation) during their deployment (Afghanistan 2003-2014) and were recruited into the ongoing ADVANCE prospective cohort study., Intervention: Not applicable., Main Outcome Measure: HRV was recorded using a single-lead ECG. HRV data were acquired during a sequential protocol of 5-minute spontaneous breathing followed immediately by 5 minutes of paced breathing (six cycles/minute) among fully rested and supine participants. HRV was reported using time domain (root mean square of successive differences), frequency domain (low frequency and high frequency) and nonlinear (sample entropy) measures. The agreement between HRV during spontaneous versus paced breathing was examined using the Bland-Altman analysis., Results: The mean age of participants was 36.5 ± 4.6 years. Resting respiratory rate was significantly higher with spontaneous versus paced breathing (13.4 ± 3.4 vs. 7.6 ± 2.0 breaths/minute; p < .001), respectively. Resting mean heart rate and root mean square of successive differences were significantly higher with paced breathing than spontaneous breathing (p < .001). Paced breathing significantly increased median low frequency power than spontaneous breathing (p < .001). No significant difference was found in the absolute power of high frequency between the two breathing protocols. The Bland-Altman analysis revealed poor agreement between HRV values during spontaneous and paced breathing conditions with wide limits of agreement., Conclusion: Slow-paced breathing leads to higher HRV than spontaneous breathing and could overestimate resting "natural-state" HRV., (© 2024 The Authors. PM&R published by Wiley Periodicals LLC on behalf of American Academy of Physical Medicine and Rehabilitation.)

Individuals with transfemoral lower limb amputations walk with adapted gait. These kinetic and kinematic compensatory strategies will manifest as differences in muscle recruitment patterns. It is important to characterize these differences to understand the reduced endurance, reduced functionality, and progression of co-morbidities in this population. This study aims to characterize muscle recruitment during gait of highly functional individuals with traumatic transfemoral amputations donning state-of-the-art prosthetics compared to able-bodied controls. Inverse dynamic and static optimisation methods of musculoskeletal modelling were used to quantify muscle forces of the residual and intact limb over a gait cycle for 11 individuals with traumatic transfemoral amputation and for 11 able-bodied controls. Estimates of peak muscle activation and impulse were calculated to assess contraction intensity and energy expenditure. The generalized estimation equation method was used to compare the maximum values of force, peak activation, and impulse of the major muscles. The force exhibited by the residual limb's iliacus, psoas major, adductor longus, tensor fasciae latae and pectineus is significantly higher than the forces in these muscles of the intact contralateral limb group and the able-bodied control group ( p < 0.001). These muscles appear to be recruited for their flexor moment arm, indicative of the increased demand due to the loss of the plantar flexors. The major hip extensors are recruited to a lesser degree in the residual limb group compared to the intact limb group ( p < 0.001). The plantar flexors of the intact limb appear to compensate for the amputated limb with significantly higher forces compared to the able-bodied controls ( p = 0.01). Significant differences found in impulse and peak activation consisted of higher values for the limbs (residual and/or intact) of individuals with transfemoral lower limb amputations compared to the able-bodied controls, demonstrating an elevated cost of gait. This study highlights asymmetry in hip muscle recruitment between the residual and the intact limb of individuals with transfemoral lower limb amputations. Overall elevated impulse and peak activation in the limbs of individuals with transfemoral amputation, compared to able-bodied controls, may manifest in the reduced walking endurance of this population. This demand should be minimised in rehabilitation protocols., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Benton, Toderita, Egginton, Liu, Amiri, Sherman, Bennett and Bull.)

Background: Heart rate variability (HRV) is a marker of autonomic function. However, the reliability of short-term HRV measurement in individuals with combat-related traumatic injury (CRTI) remains undetermined., Methods: An intra- and inter-rater reliability study was conducted using a subsample (n = 35) of British servicemen with CRTI enrolled in the ongoing ADVANCE study. A five-minute epoch of single-lead electrocardiogram data collected during spontaneous breathing was used to measure HRV. HRV analyses were independently performed by two examiners using Kubios. Intraclass correlation coefficient (ICC), standard error of measurement (SEM), minimum detectable change (MDC), and coefficient of variance were calculated for linear [root mean square of successive difference (RMSSD), standard deviation of NN interval, low-frequency, high-frequency, total power] and nonlinear (SD1-2, acceleration and deceleration capacities, sample entropy) measures. Bland-Altman %plots were used to assess bias in intra- and inter-rater HRV data., Results: The mean age of participants was 39.3 ± 6.3 years. An excellent ICC score of 0.9998 (95% CI 0.9997, 0.9999) was observed for intra-rater analyses of RMSSD, and similar excellent ICC scores were seen for all other HRV measures. The inter-rater reliability analyses produced an excellent ICC score (range 0.97-1.00). Comparatively, frequency-domain measures produced higher MDC% and SEM% scores than time-domain and nonlinear measures in both inter- and intra-rater analyses. The Bland-Altman plots revealed relatively higher bias for frequency-domain and nonlinear measures than time-domain measures., Conclusion: ECG-related short-term HRV measures were reliable in injured servicemen under spontaneous breathing. However, the reliability appeared better with the time-domain measure than frequency-domain and nonlinear measures in this sample., (© 2024 The Author(s). Annals of Noninvasive Electrocardiology published by Wiley Periodicals LLC.)

Objective: There is a lack of innovation in affordable prosthetic knee joints for children. One significant reason is the absence of technical requirements which consider the foundation of childhood: growth. This study aims to develop and use a modelling tool to determine the technical requirements throughout childhood growth for one prosthetic knee design feature, a swing phase control mechanism (SPCM)., Methods: 3D gait data of 31 able-bodied children across a range of physical maturities were analyzed. For each participant 2 models were created from a validated paediatric able-bodied musculoskeletal model. The model was first linearly scaled, then a corresponding unilateral right knee-disarticulation amputation model produced by removing segments below the knee and replacing with prosthetic componentry. Long established low-cost prosthetic componentry and a novel polycentric knee were implemented. For each participant, inverse dynamics were conducted and the SPCM torque requirements defined., Results: Prosthetic knee SPCM torque requirements were significantly less than the able-bodied knee to emulate able-bodied gait at free speed: 17.9% (± 10.2) and 66.3% (± 17.0) reduction in maximum extension and flexion torque, respectively. Maximum knee extension torque showed the strongest negative correlation with intact body mass (ρ = -0.6251) whereas flexion torque showed the strongest correlation with height (ρ = 0.6611). Corresponding linear regression fits produced RMSE of 1.91and 1.73 Nm, respectively. Results were also determined for slow and fast speeds., Conclusion: The torque requirements of an affordable paediatric prosthetic knee SPCM are defined and found to strongly correlate with parameters of childhood growth (body mass, height, and age)., Significance: Current results recommend low-cost paediatric prosthetic SPCM designs can be tailored to accommodate growth. The creation of musculoskeletal models facilitate multiple future studies.

Osteoarthritis (OA) is a common chronic disease largely driven by mechanical factors, causing significant health and economic burdens worldwide. Early detection is challenging, making animal models a key tool for studying its onset and mechanically-relevant pathogenesis. This review evaluate current use of preclinical in vivo models and progressive measurement techniques for analysing biomechanical factors in the specific context of the clinical OA phenotypes. It categorizes preclinical in vivo models into naturally occurring, genetically modified, chemically-induced, surgically-induced, and non-invasive types, linking each to clinical phenotypes like chronic pain, inflammation, and mechanical overload. Specifically, we discriminate between mechanical and biological factors, give a new explanation of the mechanical overload OA phenotype and propose that it should be further subcategorized into two subtypes, post-traumatic and chronic overloading OA. This review then summarises the representative models and tools in biomechanical studies of OA. We highlight and identify how to develop a mechanical model without inflammatory sequelae and how to induce OA without significant experimental trauma and so enable the detection of changes indicative of early-stage OA in the absence of such sequelae. We propose that the most popular post-traumatic OA biomechanical models are not representative of all types of mechanical overloading OA and, in particular, identify a deficiency of current rodent models to represent the chronic overloading OA phenotype without requiring intraarticular surgery. We therefore pinpoint well standardized and reproducible chronic overloading models that are being developed to enable the study of early OA changes in non-trauma related, slowly-progressive OA. In particular, non-invasive models (repetitive small compression loading model and exercise model) and an extra-articular surgical model (osteotomy) are attractive ways to present the chronic natural course of primary OA. Use of these models and quantitative mechanical behaviour tools such as gait analysis and non-invasive imaging techniques show great promise in understanding the mechanical aspects of the onset and progression of OA in the context of chronic knee joint overloading. Further development of these models and the advanced characterisation tools will enable better replication of the human chronic overloading OA phenotype and thus facilitate mechanically-driven clinical questions to be answered., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Xu, Kazezian, Pitsillides and Bull.)

Various non-electrocardiogram (ECG) based methods are considered reliable sources of heart rate variability (HRV) measurement. However, the ultra-short recording of a femoral arterial waveform has never been validated against the gold-standard ECG-based 300s HRV and was the aim of this study.A validity study was conducted using a sample from the first follow-up of the longitudinal ADVANCE study UK. The participants were adult servicemen (n = 100); similar in age, rank, and deployment period (Afghanistan 2003-2014). The femoral arterial waveforms (14s) from the pulse wave velocity (PWV) assessment, and ECG (300s) were recorded at rest in the supine position using the Vicorder™ and Bittium Faros™ devices, respectively, in the same session. HRV analysis was performed using Kubios Premium. Resting heart rate (HR) and root mean square of successive differences (RMSSD) were reported. The Bland-Altman %plots were constructed to explore the PWV-ECG agreement in HRV measurement. A further exploratory analysis was conducted across methods and durations.The participants' mean age was 38.0 ± 5.3 years. Both PWV-derived HR (r = 0.85) and RMSSD (r s =0.84) showed strong correlations with their 300s-ECG counterparts (p < 0.001). Mean HR was significantly higher with ECG than PWV (mean bias: -12.71 ± 7.73%, 95%CI: -14.25%, -11.18%). In contrast, the difference in RMSSD between the two methods was non-significant [mean bias: -2.90 ± 37.82% (95%CI: -10.40%, 4.60%)] indicating good agreement. An exploratory analysis of 14s ECG-vs-300s ECG measurement revealed strong agreement in both RMSSD and HR.The 14s PWV-derived RMSSD strongly agrees with the gold-standard (300s-ECG-based) RMSSD at rest. Conversely, HR appears method sensitive., (© 2024. The Author(s).)

Blast is the most common injury mechanism in conflicts of this century due to the widespread use of explosives, confirmed by recent conflicts such as in Ukraine. Data from conflicts in the last century such as Northern Ireland, the Falklands, and Vietnam up to the present day show that between 16% and 21% of personnel suffered a traumatic brain injury. Typical features of fatal brain injury to those outside of a vehicle (hereafter referred to as dismounted) due to blast include the presence of hemorrhagic brain injury alongside skull fractures rather than isolated penetrating injuries more typical of traditional ballistic head injuries. The heterogeneity of dismounted blast has meant that analysis from databases is limited and therefore a detailed look at the radiological aspects of injury is needed to understand the mechanism and pathology of dismounted blast brain injury. The aim of this study was to identify the head and spinal injuries in fatalities due to dismounted blast. All UK military fatalities from dismounted blast who suffered a head injury from 2007-2013 in the Iraq and Afghanistan conflicts were identified retrospectively. Postmortem computerized tomography images (CTPMs) were interrogated for injuries to the head, neck, and spine. All injuries were documented and classified using a radiology brain injury classification (BIC) tool. Chi-squared ( χ 2 ) and Fisher's exact tests were used to investigate correlations between injuries, along with odds ratios for determining the direction of correlation. The correlations were clustered. There were 71 fatalities from dismounted blast with an associated head injury with a CTPM or initial CT available for analysis. The results showed the heterogeneity of injury from dismounted blast but also some potential identifiable injury constellations. These were: intracranial haemorrhage, intracranial deep haemorrhage, spinal injury, and facial injury. These identified injury patterns can now be investigated to consider injury mechanisms and so develop mitigation strategies or clinical treatments. Level of Evidence: Observational. Study type: cohort observational.

Background: Chronic pain after injury poses a serious health burden. As a result of advances in medical technology, ever more military personnel survive severe combat injuries, but long-term pain outcomes are unknown. We aimed to assess rates of pain in a representative sample of UK military personnel with and without combat injuries., Methods: We used data from the ADVANCE cohort study (ISRCTN57285353). Individuals deployed as UK armed forces to Afghanistan were recruited to include those with physical combat injuries, and a frequency-matched uninjured comparison group. Participants completed self-reported questionnaires, including 'overall' pain intensity and self-assessment of post-traumatic stress disorder, anxiety, and depression., Results: A total of 579 participants with combat injury, including 161 with amputations, and 565 uninjured participants were included in the analysis (median 8 yr since injury/deployment). Frequency of moderate or severe pain was 18% (n=202), and was higher in the injured group (n=140, 24%) compared with the uninjured group (n=62, 11%, relative risk: 1.1, 95% confidence interval [CI]: 1.0-1.2, P<0.001), and lower in the amputation injury subgroup (n=31, 19%) compared with the non-amputation injury subgroup (n=109, 26%, relative risk: 0.9, 95% CI: 0.9-1.0, P=0.034). Presence of at least moderate pain was associated with higher rates of post-traumatic stress (RR: 3.7, 95% CI: 2.7-5.0), anxiety (RR: 3.2, 95% CI: 2.4-4.3), and depression (RR: 3.4, 95% CI: 2.7-4.5) after accounting for injury., Conclusion: Combat injury, but not amputation, was associated with a higher frequency of moderate to severe pain intensity in this cohort, and pain was associated with adverse mental health outcomes., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background: Limb salvage by ortho-plastic teams is the standard protocol for treating open tibial fractures in high-income countries, but there's limited research on this in conflict settings like the Gaza Strip. This study assessed the clinical impact of gunshot-related open tibial fractures, compared patient management by orthopedic and ortho-plastic teams, and identified the risk factors for bone non-union in this context., Methods: A retrospective review of medical records was conducted on Gaza Strip patients with gunshot-induced-open tibial fractures from March 2018 to October 2020. Data included patient demographics, treatments, and outcomes, with at least one year of follow-up. Primary outcomes were union, non-union, infection, and amputation., Results: The study included 244 injured individuals, predominantly young adult males (99.2%) with nearly half (48.9%) having Gustilo-Anderson type IIIB fractures and more than half (66.8%) with over 1 cm of bone loss. Most patients required surgery, including rotational flaps and bone grafts with a median of 3 admissions and 9 surgeries. Ortho-plastic teams managed more severe muscle and skin injuries, cases with bone loss > 1 cm, and performed less debridement compared to other groups, though these differences were not statistically significant. Non-union occurred in 53% of the cases, with the ortho-plastic team having the highest rate at 63.6%. Infection rates were high (92.5%), but no significant differences in bone or infection outcomes were observed among the different groups. Logistic regression analysis identified bone loss > 1 cm, vascular injury, and the use of a definitive fixator at the first application as predictors of non-union., Conclusions: This study highlights the severity and complexity of such injuries, emphasizing their significant impact on patients and the healthcare system. Ortho-plastic teams appeared to play a crucial role in managing severe cases. However, further research is still needed to enhance our understanding of how to effectively manage these injuries., (© 2024. The Author(s).)

Introduction: Combat-related traumatic injury (CRTI) adversely affects heart rate variability (HRV). The mediating effect of mental and physical health factors on the relationship between CRTI, its severity and HRV has not been previously studied and investigated., Materials and Methods: A cross-sectional mediation analysis of the ArmeD SerVices TrAuma and RehabilitatioN OutComE (ADVANCE) prospective cohort study was performed. The sample consisted of injured and uninjured British male servicemen who were frequency-matched based on their age, rank, role-in-theater, and deployment to Afghanistan (2003-2014). CRTI and injury severity (the New Injury Severity Scores [NISS] [NISS < 25 and NISS ≥ 25]) were included as exposure variables. HRV was quantified using the root mean square of successive differences (RMSSD) obtained using pulse waveform analysis. Depression and anxiety mediators were quantified using the Patient Health Questionnaire and Generalized Anxiety Disorder, respectively. Body mass index and the 6-minute walk test (6MWT) represented physical health measures. Two mediation pathways between exposure and outcome variables were examined in comparison with the uninjured group using structural equation modeling., Results: Of 862 servicemen, 428 were injured and 434 were uninjured with the mean age at assessment of 33.9 ± 5.4 (range 23-59) years. Structural equation modeling revealed that depression, anxiety, and body mass index did not significantly mediate the relationship between injury/injury severity and RMSSD. However, the 6MWT significantly mediated the relationship between CRTI and RMSSD (27% mediation). The indirect effect of 6MWT on the relationship between injury severity (NISS ≥ 25 vs. uninjured) and RMSSD was -0.06 (95% CI: -0.12, -0.00, P < .05)., Conclusions: The findings suggest that greater physical function may improve HRV following CRTI. Longitudinal studies are warranted to further validate these findings., (© The Association of Military Surgeons of the United States 2023.)

Background: Currently, there is little available in-depth analysis of the biomechanical effect of different prostheses on the musculoskeletal system function and residual limb internal loading for persons with bilateral transfemoral/through-knee amputations (BTF). Commercially available prostheses for BTF include full-length articulated prostheses (microprocessor-controlled prosthetic knees with dynamic response prosthetic feet) and foreshortened non-articulated stubby prostheses. This study aims to assess and compare the BTF musculoskeletal function and loading during gait with these two types of prostheses., Methods: Gait data were collected from four male traumatic military BTF and four able-bodied (AB) matched controls using a 10-camera motion capture system with two force plates. BTF completed level-ground walking trials with full-length articulated and foreshortened non-articulated stubby prostheses. Inverse kinematics, inverse dynamics and musculoskeletal modelling simulations were conducted., Results: Full-length articulated prostheses introduced larger stride length (by 0.5 m) and walking speed (by 0.3 m/s) than stubbies. BTF with articulated prostheses showed larger peak hip extension angles (by 10.1°), flexion moment (by 1.0 Nm/kg) and second peak hip contact force (by 3.8 bodyweight) than stubbies. There was no difference in the hip joint loading profile between BTF with stubbies and AB for one gait cycle. Full-length articulated prostheses introduced higher hip flexor muscle force impulse than stubbies., Conclusions: Compared to stubbies, BTF with full-length articulated prostheses can achieve similar activity levels to persons without limb loss, but this may introduce detrimental muscle and hip joint loading, which may lead to reduced muscular endurance and joint degeneration. This study provides beneficial guidance in making informed decisions for prosthesis choice., (© 2023. Crown.)

Circular external fixators (CEFs) are successfully used in orthopedics owing to their highly favorable stiffness characteristics which promote distraction osteogenesis. Although there are different designs of external fixators, how these features produce optimal biomechanics through structural and component designs is not well known. Therefore, the aim of this study was to conduct a review on CEFs following the PRISMA statement. A search for relevant research articles was performed on Scopus and PubMed databases providing the related keywords. Furthermore, a patent search was conducted on the Google Patent database. 126 records were found to be eligible for the review. Different designs of CEFs were summarized and tabulated based on their specific features. A bibliometric analysis was also performed on the eligible research papers. Based on the findings, the developments of CEFs in terms of materials, automation, adjustment methods, component designs, wire-clamping, and performance evaluation have been extensively discussed. The trends of the CEF design and future directions are also discussed in this review. Significant research gaps include a lack of consideration towards ease of assembly, effective wire-clamping methods, and CEFs embedded with online patient-monitoring systems, among others. An apparent lack of research interest from low-middle and low-income countries was also identified., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background: This study investigated the relationship between combat-related traumatic injury (CRTI) and its severity and predicted cardiovascular disease (CVD) risk., Material and Methods: This was an analysis of comparative 10-year predicted CVD risk (myocardial infarction, stroke or CVD-death) using the QRISK®3 scoring-system among adults recruited into the Armed Services Trauma Rehabilitation Outcome (ADVANCE) cohort study. Participants with CRTI were compared to uninjured servicemen frequency-matched by age, sex, rank, deployment (Afghanistan 2003-2014) and role. Injury severity was quantified using the New Injury Severity Score (NISS)., Results: One thousand one hundred forty four adult combat veterans were recruited, consisting of 579 injured (161 amputees) and 565 uninjured men of similar age ethnicity and time from deployment/injury. Significant mental illness (8.5% vs 4.4%; p = 0.006) and erectile dysfunction (11.6% vs 5.8%; p < 0.001) was more common, body mass index (28.1 ± 3.9 vs 27.4 ± 3.4 kg/m 2 ; p = 0.001) higher and systolic blood pressure variability (median [IQR]) (1.7 [1.2-3.0] vs 2.1 [1.2-3.5] mmHg; p = 0.008) lower among the injured versus uninjured respectively. The relative risk (RR) of predicted CVD (versus the population expected risk) was higher (RR:1.67 [IQR 1.16-2.48]) among the injured amputees versus the injured non-amputees (RR:1.60 [1.13-2.43]) and uninjured groups (RR:1.52 [1.12-2.34]; overall p = 0.015). After adjustment for confounders CRTI, worsening injury severity (higher NISS, blast and traumatic amputation) were independently associated with QRISK®3 scores., Conclusion: CRTI and its worsening severity were independently associated with increased predicted 10-year CVD risk., (© 2023. The Author(s).)

Novel sensor technology enables new insights in the neuromechanics of human locomotion that were previously not possible. Here, we provide a dataset of high-density surface electromyography (HDsEMG) and high-resolution inertial measurement unit (IMU) signals, along with motion capture and force data for the lower limb of 10 healthy adults during multiple locomotion modes. The participants performed level-ground and slope walking, as well as stairs ascent/descent, side stepping gait, and stand-to-walk and sit-to-stand-to-walk, at multiple walking speeds. These data can be used for the development and validation of locomotion mode recognition and control algorithms for prosthetics, exoskeletons, and bipedal robots, and for motor control investigations., (© 2023. The Author(s).)

Background: The relationship between acute combat-related traumatic injury (CRTI) to coronary flow reserve (CFR) and subclinical cardiovascular risk have not been examined and was the primary aim of this study., Methods and Results: UK combat veterans from the ADVANCE cohort study (UK-Afghanistan War 2003-14) with traumatic limb amputations were compared to injured non-amputees and to a group of uninjured veterans from the same conflict. Subclinical cardiovascular risk measures included fasted blood atherogenic index of plasma (AIP), triglyceride-glucose index (TyG; insulin resistance), the neutrophil-lymphocyte ratio (NLR) and high-sensitivity C-reactive protein (hs-CRP; vascular inflammation), body mass index (BMI) and visceral fat volume (dual-energy X-ray absorptiometry) and 6-min walk distance (6MWD; physical performance). The subendocardial viability ratio (SEVR), to estimate CFR, was calculated using arterial pulse waveform analysis (Vicorder device). In total 1144 adult male combat veterans were investigated, comprising 579 injured (161 amputees, 418 non-amputees) and 565 uninjured men. AIP, TyG, NLR, hs-CRP, BMI, total body fat and visceral fat volume were significantly higher and the SEVR and 6MWD significantly lower in the amputees versus the injured-non-amputees and uninjured groups. The SEVR was lowest in those with above knee and multiple limb amputations. CRTI (ExpB 0.96; 95% CI 0.94-0.98: p < 0.0001) and amputation (ExpB 0.94: 95% CI 0.91-0.97: p < 0.0001) were independently associated with lower SEVR after adjusting for age, rank, ethnicity and time from injury., Conclusion: CRTI, traumatic amputation and its worsening physical deficit are associated with lower coronary flow reserve and heightened subclinical cardiovascular risk., Competing Interests: Declaration of Competing Interest The authors have no competing interests to declare., (Crown Copyright © 2023. Published by Elsevier B.V. All rights reserved.)

Most cases of unilateral knee osteoarthritis (OA) progress to bilateral OA within 10 years. Biomechanical asymmetries have been implicated in contralateral OA development; however, gait analysis alone does not consistently detect asymmetries in OA patient gait. Stair ambulation is a more demanding activity that may be more suited to reveal between-leg asymmetries in OA patients. The objective of this study was to investigate the between-leg biomechanical differences in patients with unilateral mild-to-moderate knee OA. Sixteen unilateral mild-to-moderate medial knee OA patients and 16 healthy individuals underwent kinematic and kinetic analysis of stair ascent and descent. Stair ascent produced higher loading and muscle forces in the unaffected limb compared to the OA limb, and stair descent produced lower loading on the OA limb compared to healthy subjects. These biomechanical differences were apparent in the ankle, knee, and hip joints. The implications of these findings are that OA patients rely more heavily on their unaffected sides than the affected side in stair ascent, a strategy that may be detrimental to the unaffected joint health. The reduction in affected limb loading in stair descent is thought to be related to minimizing pain., (© 2023. The Author(s).)

Introduction: Lower limb amputation results in reduced bone mineral density (BMD) on the amputated side. Exercise interventions have proven effective in improving BMD. However, such interventions have not been attempted in an amputee population. Exercises designed for people with intact limbs may not be suitable for amputees, due to joint loss and the mechanical interface between the exercise equipment and the femoral neck being mediated through a socket. Therefore, prior to intervention implementation, it would be prudent to leverage biomechanical knowledge and clinical expertise, alongside scientific evidence in related fields, to assist in intervention development. The objective of this study is to elicit expert opinion and gain consensus to define specific exercise prescription parameters to minimise/recover BMD loss in amputees., Methods and Analysis: The Delphi technique will be used to obtain consensus among international experts; this will be conducted remotely as an e-Delphi process. 10-15 experts from ≥2 continents and ≥5 countries will be identified through published research or clinical expertise. Round 1 will consist of participants being asked to rate their level of agreement with statements related to exercise prescription to improve amputee BMD using a 5-point Likert Scale. Agreement will be deemed as ≥3 on the Likert Scale. Open feedback will be allowed in round 1 and any statement which less than 50% of the experts agree with will be excluded. Round 2 will repeat the remaining statements with the addition of any input from round 1 feedback. Round 3 will allow participants to reflect on their round 2 responses considering statistical representation of group opinion and whether they wish to alter any of their responses accordingly. Statements reaching agreement rates of 70% or above among the experts will be deemed to reach a consensus and will be implemented in a future exercise interventional trial., Ethics and Dissemination: Ethical approval was received from Imperial College Research Ethics Committee (reference: 6463766). Delphi participants will be asked to provide digital informed consent. The findings will be disseminated through peer-reviewed publications., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

The association between combat-related traumatic injury (CRTI) and bone health is uncertain. A disproportionate number of lower limb amputees from the Iraq and Afghanistan conflicts are diagnosed with osteopenia/osteoporosis, increasing lifetime risk of fragility fracture and challenging traditional osteoporosis treatment paradigms. The aim of this study is to test the hypotheses that CRTI results in a systemic reduction in bone mineral density (BMD) and that active traumatic lower limb amputees have localized BMD reduction, which is more prominent with higher level amputations. This is a cross-sectional analysis of the first phase of a cohort study comprising 575 male adult UK military personnel with CRTI (UK-Afghanistan War 2003 to 2014; including 153 lower limb amputees) who were frequency-matched to 562 uninjured men by age, service, rank, regiment, deployment period, and role-in-theatre. BMD was assessed using dual-energy X-ray absorptiometry (DXA) scanning of the hips and lumbar spine. Femoral neck BMD was lower in the CRTI than the uninjured group (T-score -0.08 versus -0.42 p = .000). Subgroup analysis revealed this reduction was significant only at the femoral neck of the amputated limb of amputees (p = 0.000), where the reduction was greater for above knee amputees than below knee amputees (p < 0.001). There were no differences in spine BMD or activity levels between amputees and controls. Changes in bone health in CRTI appear to be mechanically driven rather than systemic and are only evident in those with lower limb amputation. This may arise from altered joint and muscle loading creating a reduced mechanical stimulus to the femur resulting in localized unloading osteopenia. This suggests that interventions to stimulate bone may provide an effective management strategy. © 2023 Crown copyright and The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR). This article is published with the permission of the Controller of HMSO and the King's Printer for Scotland., (© 2023 Crown copyright and The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR). This article is published with the permission of the Controller of HMSO and the King's Printer for Scotland.)

Background: Post-traumatic growth (PTG) is a positive psychological consequence of trauma. The aims of this study were to investigate whether combat injury was associated with deployment-related PTG in a cohort of UK military personnel who were deployed to Afghanistan, and whether post-traumatic stress disorder (PTSD), depression and pain mediate this relationship., Methods: 521 physically injured ( n = 138 amputation; n = 383 non-amputation injury) and 514 frequency-matched uninjured personnel completed questionnaires including the deployment-related Post-Traumatic Growth Inventory (DPTGI). DPTGI scores were categorised into tertiles of: no/low (score 0-20), moderate (score 21-34) or a large (35-63) degree of deployment-related PTG. Analysis was completed using generalised structural equation modelling., Results: A large degree of PTG was reported by 28.0% ( n = 140) of the uninjured group, 36.9% ( n = 196) of the overall injured group, 45.4% ( n = 62) of amputee and 34.1% ( n = 134) of the non-amputee injured subgroups. Combat injury had a direct effect on reporting a large degree of PTG [Relative risk ratio (RRR) 1.59 (95% confidence interval (CI) 1.17-2.17)] compared to sustaining no injury. Amputation injuries also had a significant direct effect [RRR 2.18 (95% CI 1.24-3.75)], but non-amputation injuries did not [RRR 1.35 (95% CI 0.92-1.93)]. PTSD, depression and pain partially mediate this relationship, though mediation differed depending on the injury subtype. PTSD had a curvilinear relationship with PTG, whilst depression had a negative association and pain had a positive association., Conclusions: Combat injury, in particular injury resulting in traumatic amputation, is associated with reporting a large degree of PTG.

Purpose: A low-cost modular external fixator for the lower limb has been developed for global surgery use. The purpose of this study is to assess outcome measures in the first clinical use of the device., Methods: A prospective cohort study was conducted with patients recruited in two trauma hospitals. Initial clinical procedure data were collected, and patients were followed up every two weeks until 12 weeks or definitive fixation. Follow-up assessed infection, stability, and radiographic outcomes. In addition, patient-reported outcomes and surgeons' feedback on device usability were collected by questionnaires., Results: The external fixator was used on 17 patients. Ten were mono-lateral, five were joint spanning, and two were delta configuration. One patient had a pin site infection at 12-week follow-up. All were stable when tested mechanically and using radiographic assessment, and 53% were converted to definitive fixation., Conclusion: The low-cost external fixator developed is appropriate for use in global surgery trauma centres with good clinical outcomes., Prospective Trial Registration Number and Date: SLCTR/2021/025 (06 Sep 2021)., (© 2023. The Author(s).)

Background: This systematic review aims to ascertain how accurately 3D models can be predicted from two-dimensional (2D) imaging utilising statistical shape modelling., Methods: A systematic search of published literature was conducted in September 2022. All papers which assessed the accuracy of 3D models predicted from 2D imaging utilising statistical shape models and which validated the models against the ground truth were eligible., Results: 2127 papers were screened and a total of 34 studies were included for final data extraction. The best overall achievable accuracy was 0.45 mm (root mean square error) and 0.16 mm (average error)., Conclusion: Statistical shape modelling can predict detailed 3D anatomical models from minimal 2D imaging. Future studies should report the intended application domain of the model, the level of accuracy required, the underlying demographics of subjects, and the method in which accuracy was calculated, with root mean square error recommended if appropriate., (© 2023 The Authors. The International Journal of Medical Robotics and Computer Assisted Surgery published by John Wiley & Sons Ltd.)

Introduction: Due to loss in musculoskeletal capacity, there is an increased burden on the residual limbs of bilateral transfemoral and through-knee persons with limb loss. This reduced capacity is associated with an increased cost of walking that is detrimental to functionality. Compensatory gait strategies are adopted by this population. However, how these strategies relate to specific muscle recruitment is not known. The primary aim of this study is to characterize muscle recruitment during gait of this population. The secondary aim is to assess whether the measured kinematics can be actuated when the endurance of specific muscles is reduced and if this is the case, which alternative muscles facilitate this. Methods: 3D gait data and high-resolution magnetic resonance images were acquired from six bilateral transfemoral and through-knee persons with limb loss. Subject-specific anatomical muscle models were developed for each participant, and a validated musculoskeletal model was used to quantify muscle forces in two conditions: during normal gait (baseline) and when muscles, which were identified as functioning above a "healthy" level at baseline, have a reduced magnitude of maximum force capacity (reduced endurance simulation). To test the hypothesis that there are differences in muscle forces between the baseline trials and the simulations with reduced muscular endurance, a Bonferroni corrected two-way ANOVA with repeated measures was completed between the two states. Results: The baseline analysis showed that the hip flexors experience relatively high muscle activations during gait. The reduced endurance simulation found two scenarios. First, for 5 out of the 12 simulations, the baseline kinematics could not be reproduced with the reduced muscular capacity. Second, for 7 out of 12 cases where the baseline kinematics were achieved, this was possible with compensatory increased activation of some muscles with similar functions ( p ≤ 0.003). Discussion: Evidently, due to the loss of the ankle plantar flexors, gait imposes a high demand on the flexor muscle group of the residual limb. This study highlights how the elevated cost of gait in this population manifests in muscle recruitment. To enhance functionality, it is critical to consider the mechanical demand on the hip flexors and to develop rehabilitation interventions accordingly., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Benton, Amiri, Henson, Sivapuratharasu, Mcgregor and Bull.)

Most prosthetic limbs can autonomously move with dexterity, yet they are not perceived by the user as belonging to their own body. Robotic limbs can convey information about the environment with higher precision than biological limbs, but their actual performance is substantially limited by current technologies for the interfacing of the robotic devices with the body and for transferring motor and sensory information bidirectionally between the prosthesis and the user. In this Perspective, we argue that direct skeletal attachment of bionic devices via osseointegration, the amplification of neural signals by targeted muscle innervation, improved prosthesis control via implanted muscle sensors and advanced algorithms, and the provision of sensory feedback by means of electrodes implanted in peripheral nerves, should all be leveraged towards the creation of a new generation of high-performance bionic limbs. These technologies have been clinically tested in humans, and alongside mechanical redesigns and adequate rehabilitation training should facilitate the wider clinical use of bionic limbs., (© 2021. Springer Nature Limited.)

Major trauma is a condition that can result in severe bone damage. Customised orthopaedic reconstruction allows for limb salvage surgery and helps to restore joint alignment. For the best possible outcome three dimensional (3D) medical imaging is necessary, but its availability and access, especially in developing countries, can be challenging. In this study, 3D bone shapes of the femur reconstructed from planar radiographs representing bone defects were evaluated for use in orthopaedic surgery. Statistical shape and appearance models generated from 40 cadaveric X-ray computed tomography (CT) images were used to reconstruct 3D bone shapes. The reconstruction simulated bone defects of between 0% and 50% of the whole bone, and the prediction accuracy using anterior-posterior (AP) and anterior-posterior/medial-lateral (AP/ML) X-rays were compared. As error metrics for the comparison, measures evaluating the distance between contour lines of the projections as well as a measure comparing similarities in image intensities were used. The results were evaluated using the root-mean-square distance for surface error as well as differences in commonly used anatomical measures, including bow, femoral neck, diaphyseal-condylar and version angles between reconstructed surfaces from the shape model and the intact shape reconstructed from the CT image. The reconstructions had average surface errors between 1.59 and 3.59 mm with reconstructions using the contour error metric from the AP/ML directions being the most accurate. Predictions of bow and femoral neck angles were well below the clinical threshold accuracy of 3°, diaphyseal-condylar angles were around the threshold of 3° and only version angle predictions of between 5.3° and 9.3° were above the clinical threshold, but below the range reported in clinical practice using computer navigation (i.e., 17° internal to 15° external rotation). This study shows that the reconstructions from partly available planar images using statistical shape and appearance models had an accuracy which would support their potential use in orthopaedic reconstruction., (© 2023. The Author(s).)

Introduction: Outcomes of traumatic brain injury (TBI) are highly variable, with cognitive and psychiatric problems often present in survivors, including an increased dementia risk in the long term. Military personnel are at an increased occupational risk of TBI, with high rates of complex polytrauma including TBI characterising the UK campaign in Afghanistan. The ArmeD SerVices TrAuma and RehabilitatioN OutComE (ADVANCE)-TBI substudy will describe the patterns, associations and long-term outcomes of TBI in the established ADVANCE cohort., Methods and Analysis: The ADVANCE cohort comprises 579 military personnel exposed to major battlefield trauma requiring medical evacuation, and 566 matched military personnel without major trauma. TBI exposure has been captured at baseline using a standardised interview and registry data, and will be refined at first follow-up visit with the Ohio State Method TBI interview (a National Institute of Neurological Disorders and Stroke TBI common data element). Participants will undergo blood sampling, MRI and detailed neuropsychological assessment longitudinally as part of their follow-up visits every 3-5 years over a 20-year period. Biomarkers of injury, neuroinflammation and degeneration will be quantified in blood, and polygenic risk scores calculated for neurodegeneration. Age-matched healthy volunteers will be recruited as controls for MRI analyses. We will describe TBI exposure across the cohort, and consider any relationship with advanced biomarkers of injury and clinical outcomes including cognitive performance, neuropsychiatric symptom burden and function. The influence of genotype will be assessed. This research will explore the relationship between military head injury exposure and long-term outcomes, providing insights into underlying disease mechanisms and informing prevention interventions., Ethics and Dissemination: The ADVANCE-TBI substudy has received a favourable opinion from the Ministry of Defence Research Ethics Committee (ref: 2126/MODREC/22). Findings will be disseminated via publications in peer-reviewed journals and presentations at conferences., Competing Interests: Competing interests: HZ has served at scientific advisory boards and/or as a consultant for AbbVie, Alector, ALZPath, Annexon, Apellis, Artery Therapeutics, AZTherapies, CogRx, Denali, Eisai, Nervgen, Novo Nordisk, Pinteon Therapeutics, Red Abbey Labs, reMYND, Passage Bio, Roche, Samumed, Siemens Healthineers, Triplet Therapeutics and Wave; has given lectures in symposia sponsored by Cellectricon, Fujirebio, Alzecure, Biogen and Roche; and is a co-founder of Brain Biomarker Solutions in Gothenburg AB (BBS), which is a part of the GU Ventures Incubator Program (outside submitted work). DJS provides medicolegal services and serves on the Rugby Football Union concussion advisory board., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Post-Traumatic Stress Disorder (PTSD) has been identified as an independent risk factor for cardiovascular disease, but the mechanisms of this relationship are not well understood. This study investigates the associations between PTSD symptom clusters (hyperarousal, intrusive thoughts, avoidance behaviours and emotional numbing) and mechanisms of cardiovascular disease including cardiometabolic effects, inflammation, and haemodynamic functioning. In the ADVANCE study cohort of UK male military personnel, 1111 participants were assessed for PTSD via questionnaire and cardiovascular risk via venous blood sampling, pulse wave analysis and dual energy x-ray absorptiometry between 2015 and 2020. Variable selection procedures were conducted to assess which of the symptom clusters if any were associated with cardiovascular risk outcomes. Associations were confirmed via robust regression modelling. Avoidance behaviours were associated with greater systolic Blood Pressure (BP) (Adjusted Coefficient (AC) 0.640 (95% Confidence Interval (CI) 0.065, 1.149). Emotional numbing was associated with greater estimated glucose disposal rate (AC -0.021 (95%CI -0.036, -0.005). Hyperarousal was associated with greater levels of (log)triglycerides (exponentiated-AC 1.009 (95%CI 1.002, 1.017). Intrusive thoughts were associated with greater visceral adipose tissue (AC 0.574 (95%CI 0.020, 1.250). Nonlinear relationships were observed between emotional numbing with heart rate and intrusive thoughts with systolic BP. Limited evidence is present for symptom associations with lipoproteins and pulse wave velocity. No associations were observed between PTSD symptom clusters and high sensitivity c-reactive protein, diastolic BP, total cholesterol, or haemoglobin fasting glucose. In conclusion, symptom clusters of PTSD were associated with increased cardiovascular risk via cardiometabolic and haemodynamic functioning mechanisms, but not inflammation., Competing Interests: Declaration of competing interest S Stevelink is part funded by the National Institute for Health and Care Research (NIHR) Biomedical Research Centre at South London and Maudsley NHS Foundation Trust and King's College London, and the NIHR (ref: NIHR300592). N Fear is part funded by a grant from the UK Ministry of Defence (MoD) and is a trustee of a charity supporting the health and wellbeing of service personnel, veterans and their families. A Bennett is a serving member of the Royal Air Force. The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR, MoD or the Department of Health and Social Care., (Crown Copyright © 2023. Published by Elsevier Ltd. All rights reserved.)

Amputation imposes significant challenges in locomotion to millions of people with limb loss worldwide. The decline in the use of the residual limb results in muscle atrophy that affects musculoskeletal dynamics in daily activities. The aim of this study was to quantify the lower limb muscle volume discrepancy based on magnetic resonance (MR) imaging and to combine this with motion analysis and musculoskeletal modelling to quantify the effects in the dynamics of key activities of daily living. Eight male participants with traumatic unilateral transtibial amputation were recruited who were at least six months after receiving their definitive prostheses. The muscle volume discrepancies were found to be largest at the knee extensors (35 %, p = 0.008), followed by the hip abductors (17 %, p = 0.008). Daily activities (level walking, standing up from a chair and ascending one step) were measured in a motion analysis laboratory and muscle and joint forces quantified using a detailed musculoskeletal model for people with unilateral transtibial amputation which was calibrated in terms of the muscle volume discrepancies post-amputation at a subject-specific level. Knee extensor muscle forces were lower at the residual limb than the intact limb for all activities (p ≤ 0.008); residual limb muscle forces of the hip abductors (p ≤ 0.031) and adductors (p ≤ 0.031) were lower for standing-up and ascending one step. While the reduced knee extensor force has been reported by other studies, our results suggest a new biomechanically-based mitigation strategy to improve functional mobility, which could be achieved through strengthening of the hip abd/adductor muscles., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Crown Copyright © 2023. Published by Elsevier Ltd. All rights reserved.)

A finite-element (FE) model, previously validated for underbody blast (UBB) loading, was used here to study the effect of stature and of mitigation systems on injury risk to the leg. A range of potential UBB loadings was simulated. The risk of injury to the leg was calculated when no protection was present, when a combat boot (Meindl Desert Fox) was worn, and when a floor mat (IMPAXX TM ), which can be laid on the floor of a vehicle, was added. The risk of injury calculated indicates that the floor mat provided a statistically significant reduction in the risk of a major calcaneal injury for peak impact speeds below 17.5 m/s when compared with the scenarios in which the floor mat was not present. The risk of injury to the leg was also calculated for a shorter and a taller stature compared to that of the nominal, 50th percentile male anthropometry; shorter and taller statures were constructed by scaling the length of the tibia of the nominal stature. The results showed that there is a higher risk of leg injury associated with the short stature compared to the nominal and tall statures, whereas the leg-injury risk between nominal and tall statures was statistically similar. These findings provide evidence that the combat boot and the floor mat tested here have an attenuating effect, albeit limited to a range of possible UBB loads. The effect of stature on injury has implications on how vehicle design caters for all potential anthropometries and indeed gender, as women, on average, are shorter than men. The results from the computational simulations here complement laboratory and field experimental models of UBB, and so they contribute to the improvement of UBB safety technology and strategy., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Rebelo, Grigoriadis, Carpanen, Bull and Masouros.)

Previous research has shown that injuries to the head and neck were prevalent in 73% of all mounted fatalities of underbody blast. The mechanisms that cause such injuries to the central nervous system (CNS) are not yet known. The aim of this study was to identify the head and spinal injuries in fatalities due to underbody blast (UBB) and then develop hypotheses on the causative mechanisms. All U.K. military fatalities from UBB with an associated head injury that occurred during 2007-2013 in the Iraq and Afghanistan conflicts were identified retrospectively. Computed tomography post-mortems (CTPMs) were interrogated for injuries to the head, neck, and spine. All injuries were documented and classified using a radiology classification. Pearson's chi-square and Fisher's exact tests were used to show a relationship between variables and form a hypothesis for injury mechanisms. There were 50 fatalities from UBB with an associated head injury. Of these, 46 had complete CTPMs available for analysis. Chi-square and Fisher's exact tests showed a relationship between lateral ventricle blood and injuries to the abdomen and thorax. Five partially overlapping injury constellations were identified: 1.multiple-level spinal injury with skull fracture and brainstem injury, 2.peri-mesencephalic hemorrhage, 3.spinal and brainstem injury, 4.parenchymal contusions with injury to C0-C1, and 5.an "eggshell" pattern of fractures from direct impact. These injury constellations can now be used to propose injury mechanisms to develop mitigation strategies or clinical treatments.

Background Surgeons remain hesitant to perform biceps tenodesis in athletes with type II superior labrum anterior-to-posterior tears due to the lack of reported clinical outcomes for individual overhead throwing sports and associated concerns that this may predispose the joint to instability. This study aimed to assess the effect of biceps tenodesis on shoulder stability for major overhead throwing sports to aid sport-specific surgical decision-making for athletes with type II superior labrum anterior-to-posterior tears., Methods: This is a combined modelling and experimental study. Motion data and external forces were measured from 13 participants performing five overhead throwing motions. These data served as input into a musculoskeletal shoulder model that quantifies shoulder stability and muscle loading., Findings: The loading of the long head of the biceps brachii decreases significantly following biceps tenodesis in three overhead throwing motions (p = 0.02). The loss in joint stability following biceps tenodesis is compensated by a non-significant increase in rotator cuff muscle force which maintains shoulder stability across all overhead throwing motions, except baseball pitching (p = 0.01). The presence of a full-thickness supraspinatus tear post biceps tenodesis further decreases shoulder stability in four of the five overhead throwing motions (p = 0.01)., Interpretation: The study findings demonstrate that an increase in rotator cuff muscle force maintains joint stability for all overhead throwing motions post biceps tenodesis, except baseball pitching. As the presence of a full-thickness tear of the supraspinatus significantly reduces joint stability, biceps tenodesis may be used as a primary treatment in overhead throwing athletes with intact rotator cuff muscles, except baseball pitchers., Level of Evidence: Controlled Laboratory Study; Level of Evidence 3., Competing Interests: Declaration of Competing Interest All authors declare no conflict of interest., (Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Treating open fractures in long bones can be challenging and if not performed properly can lead to poor outcomes such as mal/non-union, deformity, and amputation. One of the most common methods of treating these fracture types is temporary external fixation followed by definitive fixation. The shortage of high-quality affordable external fixators is a long-recognised need, particularly in Low- and Middle-Income Countries (LMICs). This research aimed to develop a low-cost device that can be manufactured locally to international standards. This can provide surge capacity for conflict zones or in response to unpredictable incidents and situations. The fixator presented here and developed by us, the Imperial external fixator, was tested on femur and tibia specimens under 100 cycles of 100 N compression-tension and the results were compared with those of the Stryker Hoffmann 3 frame. The Imperial device was stiffer than the Stryker Hoffmann 3 with a lower median interfragmentary motion (of 0.94 vs. 1.48 mm). The low-cost, easy to use, relatively lightweight, and easy to manufacture (since minimum skillset and basic workshop equipment and materials are needed) device can address a critical shortage and need in LMICs particularly in conflict-affected regions with unpredictable demand and supply. The device is currently being piloted in three countries for road traffic accidents, gunshot wounds and other conflict trauma-including blast cohorts., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2022 Saeidi, Barnes, Berthaume, Holthof, Milandri, Bull and Jeffers.)

Abstract: Goodwin, JE and Bull, AMJ. Novel assessment of isometric hip extensor function: reliability, joint angle sensitivity, and concurrent validity. J Strength Cond Res 36(10): 2762-2770, 2022-Closed-chain hip extension function has not been well examined. The aim of this study was to examine the reliability, joint angle sensitivity, muscle recruitment, and concurrent validity of a force plate-based isometric hip extensor test (isometric hip thrust). All subjects were active men aged 19-29 years. In part 1, bilateral and unilateral hip extensor testing was completed on 4 occasions by 14 subjects to evaluate repeatability of force and torque measures. In part 2, joint angle sensitivity of force, torque, and surface electromyography was assessed by 10 subjects completing testing at 4 hip joint angles in a single test session. In part 3, concurrent validity of joint torque was assessed relative to standing and supine test positions on an isokinetic dynamometer, by 10 subjects in a single test session. The repeatability study found small changes in the mean from sessions 1-2 (mean standardized change d = 0.31) and close to no change in later sessions (mean d = 0.12). Typical error was predominantly low to moderate (mean 0.42), and intraclass correlation coefficient (ICC) was typically high (mean ICC = 0.87). The joint angle sensitivity study showed that increasing the hip flexion resulted in increases in peak extension force ( p = 0.001) and gluteus maximus activation ( p = 0.003) and a reduction in biceps femoris activation ( p < 0.001). There was no change in torque ( p = 0.585) and vastus lateralis activation ( p = 0.482). The concurrent validity study found that torque was correlated with supine dynamometry ( R2 = 0.555) but not with standing dynamometry ( R2 = 0.193). In summary, the isometric hip thrust is repeatable, but benefits from familiarization. Force output and muscle recruitment are sensitive to joint position, providing an opportunity to assess different functional output., (Copyright © 2021 National Strength and Conditioning Association.)