Micromotion and Push-Out Evaluation of an Additive Manufactured Implant for Above-the-Knee Amputees.

In comparison to through-knee amputees the outcomes for above-the-knee amputees are relatively poor; based on this novel techniques have been developed. Most current percutaneous implant-based solutions for transfemoral amputees make use of high stiffness intramedullary rods for skeletal fixation, which can have risks including infection, femoral fractures, and bone resorption due to stress shielding. This work details the cadaveric testing of a short, cortical bone stiffness-matched subcutaneous implant, produced using additive manufacture, to determine bone implant micromotion and push-out load. The results for the micromotions were all <20 µm and the mean push-out load was 2,099 Newtons. In comparison to a solid control, the stiffness-matched implant exhibited significantly higher micromotion distributions and no significant difference in terms of push-out load. These results suggest that, for the stiffness-matched implant at time zero, osseointegration would be facilitated and that the implant would be securely anchored. For these metrics, this provides justification for the use of a short-stem implant for transfemoral amputees in this subcutaneous application. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2104-2111, 2019.

Fatal head and neck injuries in military underbody blast casualties.

INTRODUCTION: Death as a consequence of underbody blast (UBB) can most commonly be attributed to central nervous system injury. UBB may be considered a form of tertiary blast injury but is at a higher rate and somewhat more predictable than injury caused by more classical forms of tertiary injury. Recent studies have focused on the transmission of axial load through the cervical spine with clinically relevant injury caused by resultant compression and flexion. This paper seeks to clarify the pattern of head and neck injuries in fatal UBB incidents using a pragmatic anatomical classification. METHODS: This retrospective study investigated fatal UBB incidents in UK triservice members during recent operations in Afghanistan and Iraq. Head and neck injuries were classified by anatomical site into: skull vault fractures, parenchymal brain injuries, base of skull fractures, brain stem injuries and cervical spine fractures. Incidence of all injuries and of each injury type in isolation was compared. RESULTS: 129 fatalities as a consequence of UBB were identified of whom 94 sustained head or neck injuries. 87 casualties had injuries amenable to analysis. Parenchymal brain injuries (75%) occurred most commonly followed by skull vault (55%) and base of skull fractures (32%). Cervical spine fractures occurred in only 18% of casualties. 62% of casualties had multiple sites of injury with only one casualty sustaining an isolated cervical spine fracture. CONCLUSION: Improvement of UBB survivability requires the understanding of fatal injury mechanisms. Although previous biomechanical studies have concentrated on the effect of axial load transmission and resultant injury to the cervical spine, our work demonstrates that cervical spine injuries are of limited clinical relevance for UBB survivability and that research should focus on severe brain injury secondary to direct head impact.

Defining the essential anatomical coverage provided by military body armour against high energy projectiles.

INTRODUCTION: Body armour is a type of equipment worn by military personnel that aims to prevent or reduce the damage caused by ballistic projectiles to structures within the thorax and abdomen. Such injuries remain the leading cause of potentially survivable deaths on the modern battlefield. Recent developments in computer modelling in conjunction with a programme to procure the next generation of UK military body armour has provided the impetus to re-evaluate the optimal anatomical coverage provided by military body armour against high energy projectiles. METHODS: A systematic review of the literature was undertaken to identify those anatomical structures within the thorax and abdomen that if damaged were highly likely to result in death or significant long-term morbidity. These structures were superimposed upon two designs of ceramic plate used within representative body armour systems using a computerised representation of human anatomy. RESULTS AND CONCLUSIONS: Those structures requiring essential medical coverage by a plate were demonstrated to be the heart, great vessels, liver and spleen. For the 50th centile male anthropometric model used in this study, the front and rear plates from the Enhanced Combat Body Armour system only provide limited coverage, but do fulfil their original requirement. The plates from the current Mark 4a OSPREY system cover all of the structures identified in this study as requiring coverage except for the abdominal sections of the aorta and inferior vena cava. Further work on sizing of plates is recommended due to its potential to optimise essential medical coverage.

What Is the Magnitude and Long-term Economic Cost of Care of the British Military Afghanistan Amputee Cohort?

BACKGROUND: Personal protection equipment, improved early medical care, and rapid extraction of the casualty have resulted in more injured service members who served in Afghanistan surviving after severe military trauma. Many of those who survive the initial trauma are faced with complex wounds such as multiple amputations. Although costs of care can be high, they have not been well quantified before. This is required to budget for the needs of the injured beyond their service in the armed forces. QUESTION/PURPOSES: The purposes of this study were (1) to quantify and describe the extent and nature of traumatic amputations of British service personnel from Afghanistan; and (2) to calculate an estimate of the projected long-term cost of this cohort. METHODS: A four-stage methodology was used: (1) systematic literature search of previous studies of amputee care cost; (2) retrospective analysis of the UK Joint Theatre Trauma and prosthetic database; (3) Markov economic algorithm for healthcare cost and sensitivity analysis of results; and (4) statistical cost comparison between our cohort and the identified literature. RESULTS: From 2003 to 2014, 265 casualties sustained 416 amputations. The average number of limbs lost per casualty was 1.6. The most common type of amputation was a transfemoral amputation (153 patients); the next most common amputation type was unilateral transtibial (143 patients). Using a Markov model of healthcare economics, it is estimated that the total 40-year cost of the UK Afghanistan lower limb amputee cohort is £288 million (USD 444 million); this figure estimates cost of trauma care, rehabilitation, and prosthetic costs. A sensitivity analysis on our model demonstrated a potential ± 6.19% variation in costs. CONCLUSIONS: The conflict in Afghanistan resulted in high numbers of complex injuries. Our findings suggest that a long-term facility to budget for veterans' health care is necessary. CLINICAL RELEVANCE: Estimates here should be taken as the start of a challenge to develop sustained rehabilitation and recovery funding and provision.

Ergonomic assessment of future methods of ballistic neck protection.

INTRODUCTION: Neck injuries from explosively propelled fragments are present in 11% of injured U.K. soldiers and result in significant mortality and long-term morbidity. U.S. forces in contrast sustain only neck wounds in 3 to 4% of those injured, which is believed to be because of their greater acceptance in the wearing of issued neck protection. METHOD: A three-piece neck collar, two-piece neck collar, a nape pad, a ballistic scarf, and an enhanced protection under body armor shirt (EP-UBACS) reinforced at the collar were objectively compared during a treadmill test using physiological measurements. Designs were subjectively compared regarding their effect on soldier performance using representative military tasks. RESULTS: Both neck collars and the EP-UBACS prototype demonstrated 90% acceptability in terms of military task performance. No statistical difference in tympanic temperature and heart rate was found between prototypes. The statistically significant higher skin temperatures found for prototypes lying close to the skin (EP-UBACS and ballistic scarf) were unrelated to perceived comfort. DISCUSSION: Neck collars remain the most successful design in terms of military performance, comfort, and potential levels of ballistic protection. However the EP-UBACS concept should also be developed further, with future iterations potentially removing the zip and increasing skin standoff.

Use and complications of operative control of arterial inflow in combat casualties with traumatic lower-extremity amputations caused by improvised explosive devices.

BACKGROUND: Proximal traumatic lower-extremity amputation has become the signature injury of the war in Afghanistan. Casualties present in extremis and often require immediate operative control of arterial inflow to prevent exsanguination. This study evaluated the use of this strategy and its complications. METHODS: This is a retrospective analysis of case notes of UK service personnel, identified from the UK Joint Theatre Trauma Registry, who sustained traumatic lower-extremity amputation requiring suprainguinal vascular control, following improvised explosive device injury in Afghanistan, between July 2008 and December 2010. RESULTS: Fifty-one casualties were identified with a median Injury Severity Score (ISS) of 30. In 10 casualties, control was obtained via an extraperitoneal approach, and in 41, control was obtained via midline laparotomy and intraperitoneal (IP) approach. The most commonly controlled vessel in extraperitoneal control was the external iliac artery, and in IP control, the common iliac artery. Within the 41 patients who had IP control, 13 also required a therapeutic laparotomy, and 9 patients had bilateral injuries at the level of the proximal femur or higher. One patient, who had undergone IP control, experienced an injury to the common iliac vein, which was repaired. There were no other immediate complications recorded, and 39 casualties survived to discharge. CONCLUSION: This is the first study to characterize the methods of proximal control in high wartime lower-extremity amputees. Although some casualties will have abdominal injuries that necessitate laparotomy, the majority in our study did not; however, in the critically ill casualty, rapid proximal control is required. Novel methods of temporary hemorrhage control may reduce the need for, and burden of, cavity surgery. LEVEL OF EVIDENCE: Epidemiologic study, level III; prognostic study, level IV.

Primary blast lung injury prevalence and fatal injuries from explosions: insights from postmortem computed tomographic analysis of 121 improvised explosive device fatalities.

BACKGROUND: Primary blast lung injury (PBLI) is an acknowledged cause of death in explosive blast casualties. In contrast to vehicle occupants following an in-vehicle explosion, the injury profile, including PBLI incidence, for mounted personnel following an external explosion has yet to be as well defined. METHODS: This retrospective study identified 146 cases of UK military personnel killed by improvised explosive devices (IEDs) between November 2007 and July 2010. With the permission of Her Majesty's Coroners, relevant postmortem computed tomography imaging was analyzed. PBLI was diagnosed by postmortem computed tomography. Injury, demographic, and relevant incident data were collected via the UK Joint Theatre Trauma Registry. RESULTS: Autopsy results were not available for 1 of 146 cases. Of the remaining 145 IED fatalities, 24 had catastrophic injuries (disruptions), making further study impossible, leaving 121 cases; 79 were dismounted (DM), and 42 were mounted (M). PBLI was noted in 58 cases, 33 (79%) of 42 M fatalities and 25 (32%) of 79 DM fatalities (p < 0.0001). Rates of associated thoracic trauma were also significantly greater in the M group (p < 0.006 for all). Fatal head (53% vs. 23%) and thoracic trauma (23% vs. 8%) were both more common in the M group, while fatal lower extremity trauma (7% vs. 48%) was more commonly seen in DM casualties (p < 0.0001 for all). CONCLUSION: Following IED strikes, mounted fatalities are primarily caused by head and chest injuries. Lower extremity trauma is the leading cause of death in dismounted fatalities. Mounted fatalities have a high incidence of PBLI, suggesting significant exposure to primary blast. This has not been reported previously. Further work is required to determine the incidence and clinical significance of this severe lung injury in explosive blast survivors. In addition, specific characteristics of the vehicles should be considered.

Design of a traumatic injury simulator for assessing lower limb response to high loading rates.

Current military conflicts are characterized by the use of the improvised explosive device. Improvements in personal protection, medical care, and evacuation logistics have resulted in increasing numbers of casualties surviving with complex musculoskeletal injuries, often leading to life-long disability. Thus, there exists an urgent requirement to investigate the mechanism of extremity injury caused by these devices in order to develop mitigation strategies. In addition, the wounds of war are no longer restricted to the battlefield; similar injuries can be witnessed in civilian centers following a terrorist attack. Key to understanding such mechanisms of injury is the ability to deconstruct the complexities of an explosive event into a controlled, laboratory-based environment. In this article, a traumatic injury simulator, designed to recreate in the laboratory the impulse that is transferred to the lower extremity from an anti-vehicle explosion, is presented and characterized experimentally and numerically. Tests with instrumented cadaveric limbs were then conducted to assess the simulator's ability to interact with the human in two mounting conditions, simulating typical seated and standing vehicle passengers. This experimental device will now allow us to (a) gain comprehensive understanding of the load-transfer mechanisms through the lower limb, (b) characterize the dissipating capacity of mitigation technologies, and (c) assess the bio-fidelity of surrogates.

Outcomes of IED foot and ankle blast injuries.

BACKGROUND: Improvements in protection and medical treatments have resulted in increasing numbers of modern-warfare casualties surviving with complex lower-extremity injuries. To our knowledge, there has been no prior analysis of foot and ankle blast injuries as a result of improvised explosive devices (IEDs). The aims of this study were to report the pattern of injury and determine which factors are associated with a poor clinical outcome. METHODS: U.K. service personnel who had sustained lower leg injuries following an under-vehicle explosion from January 2006 to December 2008 were identified with the use of a prospective trauma registry. Patient demographics, injury severity, the nature of the lower leg injury, and the type of clinical management were recorded. Clinical end points were determined by (1) the need for amputation and (2) ongoing clinical symptoms. RESULTS: Sixty-three U.K. service personnel (eighty-nine injured limbs) with lower leg injuries from an explosion were identified. Fifty-one percent of the casualties sustained multisegmental injuries to the foot and ankle. Twenty-six legs (29%) required amputation, with six of them amputated because of chronic pain eighteen months following injury. Regression analysis revealed that hindfoot injuries, open fractures, and vascular injuries were independent predictors of amputation. At the time of final follow-up, sixty-six (74%) of the injured limbs had persisting symptoms related to the injury, and only nine (14%) of the service members were fit to return to their preinjury duties. CONCLUSIONS: This study demonstrates that foot and ankle injuries from IEDs are associated with a high amputation rate and frequently with a poor clinical outcome. Although not life-threatening, they remain a source of long-term morbidity in an active population.

FASS is a better predictor of poor outcome in lower limb blast injury than AIS: implications for blast research.

OBJECTIVES: Due to the absence of clinical blast data, automotive injury data using the abbreviated injury score (AIS) has been extrapolated to define current North Atlantic Treaty Organisation (NATO) injury thresholds for anti-vehicle mine tests. We hypothesized that AIS, being a marker of fatality rather than disability, would be a worse predictor of poor clinical outcome compared with the lower limb-specific foot and ankle severity score (FASS). METHODS: Using a prospectively collected trauma database, we identified UK Service Personnel sustaining lower leg injuries from under-vehicle explosions from January 2006 to December 2008. A full review of all medical documentation was performed to determine patient demographics and the severity of lower leg injury, as assessed by AIS and FASS. Clinical endpoints were defined as (1) need for amputation or (2) poor clinical outcome (defined as amputation or ongoing clinical problems). Statistical models were developed to explore the relationship between the scoring systems and clinical endpoints. RESULTS: Sixty-three UK casualties (89 limbs) were identified with a lower limb injury after under-vehicle explosion. The mean age of the casualty was 26.0 years. At 33.6 months follow-up, 29.1% (26 of 89) required an amputation and 74.6% (67 of 89) having a poor clinical outcome. Only 9 (14%) casualties were deemed medically fit to return to full military duty. Receiver operating characteristic analysis revealed that both AIS = 2 and FASS = 4 could predict the risk of amputation, with FASS = 4 demonstrating greater specificity (43% vs. 20%) and greater positive predictive value (72% vs. 34%). In predicting poor clinical outcome, FASS was significantly superior to AIS. Probit analysis revealed that a relationship could not be developed between AIS and the probability of a poor clinical outcome. CONCLUSIONS: Our study clearly demonstrates that AIS is not a predictor of long-term clinical outcome and that FASS would be a better quantitative measure of lower limb injury severity.

The development of an experimental model of contaminated muscle injury in rabbits.

Extent of tissue trauma and contamination determine outcome in extremity injury. In contrast to fracture, osteomyelitis, and closed muscle injury studies, there are limited small animal models of extremity muscle trauma and contamination. To address this we developed a model of contaminated muscle injury in rabbits. Twenty-eight anesthetized New Zealand White rabbits underwent open controlled injury of the flexor carpi ulnaris (FCU). Twenty-two animals had subsequent contamination of the injured muscle with Staphylococcus aureus. All animals were sacrificed at 48 hours and the level of muscle injury and contamination determined by quantitative histological and microbiological analysis. A 1-kg mass dropped 300 mm onto the mobilized FCU resulted in localized necrosis of the muscle belly. Delivery of a mean challenge of 3.71 × 10(6) cfu/100 µL S aureus by droplet spread onto the injured muscle produced a muscle contamination of 8.79 × 10(6) cfu/g at 48 hours. Ipsilateral axillary lymph nodes demonstrated clinically significant activation. All animals had normal body temperature and hematological parameters throughout and blood and urinalysis culture at autopsy were negative for organisms. This model allows reproducible muscle injury and contamination with the organism ubiquitous to extremity wound infection at a level sufficient to allow quantitative assessment of subsequent wound care interventions without incurring systemic involvement.

Extremity trauma, dressings, and wound infection: should every acute limb wound have a silver lining?

The manner in which high-energy transfer limb injuries are dressed can alter the wound environment through manipulation of the bacterial burden, thus minimizing tissue degradation and influencing healing potential. Infection is the principal complication of such wounds, and antiseptic soaked gauze is accepted in early coverage of extremity wounds despite a lack of evidence to support this practice. There has been resurgence in the use of silver in acute wounds, through dressings manipulated to deliver sustained elemental silver to the wound interface. In vitro and in vivo experimentation of silver dressings are characterized however by methodological compromise, primarily through lack of similarity of models to the physiology of the healing wound. Results from in vitro studies caution against the use of silver because of evidence of cytotoxicity, but this is not reproduced in in vivo or clinical experimentation, leading to ambiguity. Review of silver dressing application in burns and chronic wound studies fails to support its use over other dressing systems. Similarly, evidence for the use of silver in acute limb wounds is lacking. This article provides a comprehensive overview of the use of silver dressings in acute wound care and highlights in particular the paucity of evidence regarding its routine use in extremity injury.

Limb wounding and antisepsis: iodine and chlorhexidine in the early management of extremity injury.

Extremity injury and contamination as consequence are features of high-energy wounding. A leading cause of disability and the commonest cause of late complications, prevention of wound infection determines the ultimate outcome in these populations. Multiple variables influence the development of infection, one of which is the dressing used on the wound. Antiseptic-soaked gauze dressings feature in the early management of limb trauma despite a lack of evidence to support this. Iodine and chlorhexidine are ubiquitous in other aspects of health care however, and a plethora of studies detail their role in skin antisepsis, the recommendations from which are often anecdotally applied to acute wounding. To contextualize the role for antiseptic dressing use in acute, significant limb injury this review explores the evidence for the use of chlorhexidine and iodine in skin antisepsis. The paucity of experimental data available for antiseptic use in early wound management and the need for further research to address this evidence void is highlighted.

The modern "deck-slap" injury--calcaneal blast fractures from vehicle explosions.

BACKGROUND: Anti-vehicle mines and improvised explosive devices remain the most prevalent threat to coalition troops operating in Iraq and Afghanistan. Detonation of these devices causes rapid deflection of the vehicle floor resulting in severe injuries to calcaneus. Anecdotally referred to as a "deck-slap" injury, there have been no studies evaluating the pattern of injury or the effect of these potentially devastating injuries since World War II. Therefore, the aim of this study is to determine the pattern of injury, medical management, and functional outcome of UK Service Personnel sustaining calcaneal injuries from under-vehicle explosions. METHOD: From January 2006 to December 2008, using a prospectively collected trauma registry (Joint Theater Trauma Registry), the records of all UK Service Personnel sustaining a fractured calcaneus from a vehicle explosion were identified for in-depth review. For each patient, demographic data, New Injury Severity Score, and associated injuries were recorded. In addition, the pattern of calcaneal fracture, the method of stabilization, local complications, and the need for amputation were noted. Functional recovery was related to the ability of the casualty to return to military duties. RESULTS: Forty calcaneal fractures (30 patients) were identified in this study. Mean follow-up was 33.2 months. The median New Injury Severity Score was 17, with the lower extremity the most severely injured body region in 90% of cases. Nine (30%) had an associated spinal injury. The overall amputation rate was 45% (18/40); 11 limbs (28%) were amputated primarily, with a further 3 amputated on return to the United Kingdom. Four (10%) casualties required a delayed amputation for chronic pain (mean, 19.5 months). Of the 29 calcaneal fractures salvaged at the field hospital, wound infection developed in 11 (38%). At final follow-up, only 2 (6%) were able to return to full military duty with 23 (76%) only fit for sedentary work or unfit for any military duty. CONCLUSION: Calcaneal injuries following under-vehicle explosions are commonly associated with significant multiple injuries including severe lower limb injury. The frequency of associated spinal injuries mandates radiologic evaluation of the spine in all such patients. The severity of the hindfoot injury is reflected by the high infection rate and amputation rate. Only a small proportion of casualties were able to return to preinjury military duties.

Executive summary: Guidelines for the prevention of infections associated with combat-related injuries: 2011 update: endorsed by the Infectious Diseases Society of America and the Surgical Infection Society.

Despite advances in resuscitation and surgical management of combat wounds, infection remains a concerning and potentially preventable complication of combat-related injuries. Interventions currently used to prevent these infections have not been either clearly defined or subjected to rigorous clinical trials. Current infection prevention measures and wound management practices are derived from retrospective review of wartime experiences, from civilian trauma data, and from in vitro and animal data. This update to the guidelines published in 2008 incorporates evidence that has become available since 2007. These guidelines focus on care provided within hours to days of injury, chiefly within the combat zone, to those combat-injured patients with open wounds or burns. New in this update are a consolidation of antimicrobial agent recommendations to a backbone of high-dose cefazolin with or without metronidazole for most postinjury indications and recommendations for redosing of antimicrobial agents, for use of negative pressure wound therapy, and for oxygen supplementation in flight.

Guidelines for the prevention of infections associated with combat-related injuries: 2011 update: endorsed by the Infectious Diseases Society of America and the Surgical Infection Society.

Despite advances in resuscitation and surgical management of combat wounds, infection remains a concerning and potentially preventable complication of combat-related injuries. Interventions currently used to prevent these infections have not been either clearly defined or subjected to rigorous clinical trials. Current infection prevention measures and wound management practices are derived from retrospective review of wartime experiences, from civilian trauma data, and from in vitro and animal data. This update to the guidelines published in 2008 incorporates evidence that has become available since 2007. These guidelines focus on care provided within hours to days of injury, chiefly within the combat zone, to those combat-injured patients with open wounds or burns. New in this update are a consolidation of antimicrobial agent recommendations to a backbone of high-dose cefazolin with or without metronidazole for most postinjury indications, and recommendations for redosing of antimicrobial agents, for use of negative pressure wound therapy, and for oxygen supplementation in flight.

Prevention of infections associated with combat-related extremity injuries.

During combat operations, extremities continue to be the most common sites of injury with associated high rates of infectious complications. Overall, ∼ 15% of patients with extremity injuries develop osteomyelitis, and ∼ 17% of those infections relapse or recur. The bacteria infecting these wounds have included multidrug-resistant bacteria such as Acinetobacter baumannii, Pseudomonas aeruginosa, extended-spectrum ß-lactamase-producing Klebsiella species and Escherichia coli, and methicillin-resistant Staphylococcus aureus. The goals of extremity injury care are to prevent infection, promote fracture healing, and restore function. In this review, we use a systematic assessment of military and civilian extremity trauma data to provide evidence-based recommendations for the varying management strategies to care for combat-related extremity injuries to decrease infection rates. We emphasize postinjury antimicrobial therapy, debridement and irrigation, and surgical wound management including addressing ongoing areas of controversy and needed research. In addition, we address adjuvants that are increasingly being examined, including local antimicrobial therapy, flap closure, oxygen therapy, negative pressure wound therapy, and wound effluent characterization. This evidence-based medicine review was produced to support the Guidelines for the Prevention of Infections Associated With Combat-Related Injuries: 2011 Update contained in this supplement of Journal of Trauma.

Evaluating the effect of vehicle modification in reducing injuries from landmine blasts. An analysis of 2212 incidents and its application for humanitarian purposes.

INTRODUCTION: Anti-vehicle (AV) mines have been laid indiscriminately in conflict areas for the past 100 years. With an indeterminate life-span they continue to pose a significant threat to the civilian population, as well as restrict the movement of people, aid and goods to vulnerable populations. The aim of this study was to analyse unique casualty data from 2212 mine incidents to determine if simple vehicle modifications can reduce fatality and injury rates from mine explosions. METHOD: We analysed casualty data from the Rhodesian War (1972-1980), to assess the effects of basic vehicle modifications (V-shaped hull, increased ground clearance, widened axles, heavy vehicles and blast deflectors) on injury rates. A multinomial regression statistical model was developed for vehicle modifications and number of alterations to explore these effects. RESULTS: Incident data was available on 2212 vehicle mine incidents involving 16,456 people. The overall fatality rate was 3.3% (544/16,456) and the overall injury rate was 22.7% (3741/16,456). Explosions against mine-protected vehicles resulted in a fatality rate of 1.2% (150/12,919); occupants in unprotected vehicles sustained a fatality rate of 11.4% (395/3537). The injury rate in mine protected vehicles was 22.2% (2868/12,919) compared to 24.7% in unprotected vehicles (873/3537). Utilising a multinomial logistical-regression model, we show that each design feature significantly reduced fatality rate (from 45% in unprotected vehicles to 0.8% in protected vehicles); each of these designs had a cumulative effect in fatality reduction. In isolation, blast deflectors, whilst reducing fatality rates, increased injury rates. CONCLUSIONS: Our data clearly demonstrates that simple vehicle modifications can have a significant effect on reducing fatality and injury rates from AV mine explosions. Given that the modifications described were produced using commercially available vehicles with basic engineering requirements, we believe that similar processes could be employed in post-conflict environments in a cost-effective manner.

Blast-related fracture patterns: a forensic biomechanical approach.

Improved protective measures and medical care has increased the survivability from battlefield injuries. In an attempt to reduce the debilitating consequences of blast injury, understanding and mitigating the effects of explosion on the extremities is key. In this study, forensic biomechanical analyses have been applied to determine mechanisms of injury after the traumatic event. The aims of this study were (i) to determine which effects of the explosion are responsible for combat casualty extremity bone injury in two distinct environments, namely open, free-field (open group), and in vehicle or in cover (enclosed group), and (ii) to determine whether patterns of combat casualty bone injury differed between environments. Medical records of casualties admitted to a military hospital in Afghanistan were reviewed over a six-month period. Explosive injuries have been sub-divided traditionally into primary, secondary and tertiary effects. All radiographs were independently reviewed by a military radiologist, a team of military orthopaedic surgeons and a team of academic biomechanists, in order to determine 'zones of injury' (ZoIs), and their related mechanisms. Sixty-two combat casualties with 115 ZoIs were identified. Thirty-four casualties in the open group sustained 56 ZoIs; 28 casualties in the enclosed group sustained 59 ZoIs. There was no statistical difference in mean ZoIs per casualty between groups (p = 0.54). There was a higher proportion of lower limb injuries in the enclosed group compared with the open group (p < 0.05). Of the casualties in the open group, 1 ZoI was owing to the primary effects of blast, 10 owing to a combination of primary and secondary blast effects, 23 owing to secondary blast effects and 24 owing to tertiary blast effects. In contrast, tertiary blast effects predominated in the enclosed group, accounting for 96 per cent of ZoIs. These data clearly demonstrate two distinct injury groups based upon the casualties' environment. The enclosed environment appears to attenuate the primary and secondary effects of the explosion. However, tertiary blast effects were the predominant mechanism of injury, with severe axial loading to the lower extremity being a characteristic of the fractures seen. The development of future mitigation strategies must focus on reducing all explosion-related injury mechanisms. Integral to this process is an urgent requirement to better understand the behaviour of bone in this unique environment.

In-vehicle extremity injuries from improvised explosive devices: current and future foci.

The conflicts in Iraq and Afghanistan have been epitomized by the insurgents' use of the improvised explosive device against vehicle-borne security forces. These weapons, capable of causing multiple severely injured casualties in a single incident, pose the most prevalent single threat to Coalition troops operating in the region. Improvements in personal protection and medical care have resulted in increasing numbers of casualties surviving with complex lower limb injuries, often leading to long-term disability. Thus, there exists an urgent requirement to investigate and mitigate against the mechanism of extremity injury caused by these devices. This will necessitate an ontological approach, linking molecular, cellular and tissue interaction to physiological dysfunction. This can only be achieved via a collaborative approach between clinicians, natural scientists and engineers, combining physical and numerical modelling tools with clinical data from the battlefield. In this article, we compile existing knowledge on the effects of explosions on skeletal injury, review and critique relevant experimental and computational research related to lower limb injury and damage and propose research foci required to drive the development of future mitigation technologies.