Aims. In recent conflicts, most injuries to the limbs are due to blasts resulting in a large number of lower limb amputations. These lead to heterotopic ossification (HO), phantom limb pain (PLP), and functional deficit. The mechanism of blast loading produces a combined fracture and amputation. Therefore, to study these conditions, in vivo models that replicate this combined effect are required. The aim of this study is to develop a preclinical model of blast-induced lower limb amputation. Methods. Cadaveric Sprague-Dawley rats’ left hindlimbs were exposed to blast waves of 7 to 13 bar burst pressures and 7.76 ms to 12.68 ms positive duration using a shock tube. Radiographs and dissection were used to identify the injuries. Results. Higher burst pressures of 13 and 12 bar caused multiple fractures at the hip, and the right and left limbs. Lowering the pressure to 10 bar eliminated hip fractures; however, the remaining fractures were not isolated to the left limb. Further reducing the pressure to 9 bar resulted in the desired isolated fracture of the left tibia with a dramatic reduction in the fractures to other sites. Conclusion. In this paper, a rodent blast injury model has been developed in the hindlimb of cadaveric rats that combines the blast and fracture in one insult, necessitating amputation. Experimental setup with 9 bar burst pressure and 9.13 ms positive duration created a fracture at the tibia with total reduction in non-targeted fractures, rendering 9 bar burst pressure suitable for translation to a survivable model to investigate blast injury-associated diseases. Cite this article: Bone Joint Res 2021;10(3):166–173

The defining weapon of the conflicts in Iraq and Afghanistan has been the Improvised Explosive Device (IEDs). When detonated under a vehicle, they result in significant axial loading to the lower limbs, resulting in devastating injuries. Due to the absence of clinical blast data, automotive injury data using the Abbreviated Injury Score (AIS) has been extrapolated to define current NATO injury thresholds for Anti-vehicle (AV) mine tests. We hypothesized that AIS, being a marker of fatality rather than disability would be a worse predictor of poor clinical outcome compared to the lower limb specific Foot and Ankle Severity Score (FASS). Using a prospectively collected trauma database, we identified UK Service Personnel sustaining lower leg injuries from under-vehicle explosions from Jan 2006–Dec 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 (i) need for amputation or (ii) poor clinical outcome. Statistical models were developed in order to explore the relationship between the scoring systems and clinical endpoints. 63 UK casualties (89 limbs) were identified with a lower limb injury following under-vehicle explosion. The mean age of the casualty was 26.0 yrs. At 33.6 months follow-up, 29.1% (26/89) required an amputation and a further 74.6% (41/89) having a poor clinical outcome (amputation or ongoing clinical problems). Only 9(14%) casualties were deemed medically fit to return to full military duty. ROC 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 32%). In predicting poor clinical outcome, FASS was significantly superior to AIS (p<0.01). Probit analysis revealed that a relationship could not be developed between AIS and the probability of a poor clinical outcome (p=0.25). Foot and ankle injuries following AV mine blast are associated with significant morbidity. 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. There is a requirement to reassess the current injury criteria used to evaluate the potential of mitigation technologies to help reduce long-term disability in military personnel. Our study highlights the critical importance of utilising contemporary battlefield injury data in order to ensure that the evaluation of mitigation measures is appropriate to the injury profile and their long-term effects

Background. The conflict in Afghanistan has been epitomised by the emergence of the Improvised Explosive Device (IEDs). Improvements in protection and medical treatments have resulted in increasing numbers of casualties surviving with complex lower extremity injuries. To date, there has been no analysis of foot and ankle blast injuries as a result of IEDs. Therefore the aims of this study are to report the pattern of injury and determine which factors were associated with a poor clinical outcome. Methods. Using a prospective trauma registry, UK Service Personnel who sustained lower leg injuries following an under-vehicle explosion between Jan 2006 and Dec 2008 were identified. Patient demographics, injury severity, the nature of lower limb injury and clinical management was recorded. Clinical endpoints were determined by . (i). need for amputation and. (ii). need for ongoing clinical output at mean 33.0 months follow-up. Results. 63 UK Service Personnel (89 injured limbs) were identified with lower leg injuries from explosion. 50% of casualties sustained multi-segmental injuries to the foot and ankle complex. 26(29%) limbs required amputation, with six amputated for chronic pain 18 months following injury. Regression analysis revealed that hindfoot injuries, open fractures and vascular injuries were independent predictors of amputation. Of the 69 limbs initially salvaged, the overall infection rate was 42%, osteomyelitis 11.6% and non-union rates was 21.7%. Symptomatic traumatic osteoarthritis was noted in 33.3% salvaged limbs. At final follow-up, 66(74%) of injured limbs had persisting symptoms related to their injury, with only 9(14%) fit to return to their pre-injury duties. Conclusions. This study demonstrates that foot and ankle injuries from IEDs are frequently associated with a high amputation rate and poor clinical outcome. Although, not life-threatening, they remain a source of long-term morbidity in an active population. Primary prevention of these injuries remain key in reducing the injury burden

The conflict in Afghanistan has been epitomised by the emergence of the Improvised Explosive Device(IEDs). Improvements in medical treatments have resulted in increasing numbers of casualties surviving with complex lower extremity injuries. To date, there has been no analysis of foot and ankle blast injuries as a result of IEDs. Therefore the aims of this study are to firstly report the pattern of injury and secondly determine which factors were associated with a poor clinical outcome in order to focus future research. Using a prospective trauma registry, UK Service Personnel who sustained lower leg injuries following an under-vehicle explosion between Jan 2006 and Dec 2008 were identified. Patient demographics, injury severity, the nature of lower limb injury and clinical management was recorded. Clinical endpoints were determined by (i)need for amputation and (ii)need for ongoing clinical output at mean 33.0 months follow-up. 63 UK Service Personnel (89 injured limbs) were identified with lower leg injuries from explosion. 50% of casualties sustained multi-segmental injuries to the foot and ankle complex. 26(29%) limbs required amputation, with six amputated for chronic pain 18 months following injury. Regression analysis revealed that hindfoot injuries, open fractures and vascular injuries were independent predictors of amputation. Of the 69 limbs initially salvaged, the overall infection rate was 42%, osteomyelitis 11.6% and non-union rates was 21.7%. Symptomatic traumatic osteoarthritis was noted in 33.3% salvaged limbs. At final follow-up, 66(74%) of injured limbs had persisting symptoms related to their injury, with only 9(14%) fit to return to their pre-injury duties. This study demonstrates that foot and ankle injuries from IEDs are frequently associated with a high amputation rate and poor clinical outcome. Although, not life-threatening, they remain a source of long-term morbidity in an active population. Primary prevention of these injuries remain key in reducing the injury burden

The mechanism of traumatic amputation (TA) from explosive blast has traditionally been considered to be a combination of blast wave induced bone injury – primary blast - followed by limb avulsion from the blast wind – tertiary blast. This results in a transosseous TA, with through joint amputations considered to be extremely rare. Data from previous conflicts has also suggested that this injury is frequently associated with a non-survivable primary blast lung injury (PBLI), further linking the extremity injury to the primary blast wave. However, our current experience in the Middle East would suggest that both the mechanism of TA and the link with fatal primary blast exposure need to be reconsidered. The aim of this study was to analyse the injury profile of the current cohort of TA fatalities to further investigate the underlying blast injury mechanism and to allow hypotheses on injury mechanisms to be developed for further analysis. With the permission of the coroners, 121 post-mortem CT (PMCT) scans of UK Armed Forces personnel who died following an IED blast were analysed. All orthopaedic injuries were identified, classified and the anatomical level of any associated soft tissue injury noted. PMCT evidence of PBLI was used as a marker of significant primary blast exposure. 75/121 (62%) sustained at least 1 TA, with 138 TAs seen in total. 31/138 (22%) were through joints, with through knee amputations most common (23/31, 74%). Only 7/31(23%) through joint amputations had an associated fracture proximal to and contiguous with the amputation site. The soft tissue injury profile of through joint and transosseous TAs were not significantly different (p=0.569). When fatality location was considered (i.e. mounted or dismounted), no overall relationship between PBLI and TA was evident. The two pathologies were not seen to consistently occur concurrently, as has been previously reported. The accepted mechanism for traumatic amputation following explosive blast does not adequately explain the significant number of through joint TAs presented here. The previously reported link between TA and PBLI in fatalities was not supported by this analysis of modern combat blast fatalities. Lack of an associated fracture with the majority of through joint TAs in conjunction with a lesser contribution of primary blast may implicate flail and periarticular soft tissue failure as a potential injury mechanism. Analysis of through joint TA incidence and associated injuries in survivors is now indicated. Case studies within the fatality dataset may facilitate generation of injury mechanism hypotheses. To further investigate the injury mechanism, work is required to understand osseous, ligamentous and other soft tissue behaviour and failure at high strain rates. This should allow characterisation and modeling of these injuries and inform mitigation strategies

Improvised Explosive Device (IED) attacks on vehicles have been a significant feature of recent conflicts. The Dynamic Response Index (DRI), developed for predicting spinal injury in aircraft ejection, has been adopted for testing vehicles in underbelly blast. Recent papers suggest that DRI is not accurate in blast conditions. We suggest that the distribution of blast and ejection injuries is different. A literature review identified the distribution of spinal fractures in aircraft ejection incidents. A Joint Theatre Trauma Registry search identified victims of mounted IED blast with spinal fractures. The distribution of injuries in the two groups was compared using the Kruskall Wallis test. 329 fractures were identified in ejector seat incidents; 1% cervical, 84% thoracic and 16% lumbar. 245 fractures were identified in victims of mounted blast; 16% cervical, 34% thoracic and 50% lumbar. There was no significant similarity between the two (p=1). There was no statistically significant difference between the distribution of fractures in blast survivors versus fatalities. The difference between blast and ejection injury patterns suggests that injury prediction models for ejection should not be extrapolated to blast mechanisms and that new models need to be developed

Introduction. This study reviews the orthopaedic care of the thirteen patients who were admitted and treated at Royal Manchester Children's' Hospital following the Manchester Arena Bomb blast. Methods. We included all children admitted to Royal Manchester Children's Hospital injured following the bomb blast who either suffered upper limb, lower limb or pelvic fractures, or penetrating upper or lower limb wounds. The nature of each patient's bone and soft tissue injuries, initial and definitive management, and outcome were assessed and documented. Main outcome measures were time to fracture union, time to definitive soft tissue/skin healing, and functional outcome. Findings. Thirteen children were admitted with orthopaedic injuries; 12 were female and mean age was 12.69. All patients had penetrating deep wounds with at least one large nut foreign body in situ, two patients suffered significant burn injury, one patient required amputation of two digits, and two patients required local flap reconstruction. There were a total of 29 upper and lower limb fractures in nine of the patients, with the majority managed without internal or external fixation. In only half of the patients all fractures showed full radiological union at 6 months follow up. There was significant morbidity with several patients suffering long term physical and psychological disability and one patient still in hospital. Conclusion. We found that stable fractures in children secondary to blast injuries can often be appropriately managed without metalwork, and penetrating wounds can be managed without the need for skin graft/flap reconstruction. Our study documents the severe nature of the injuries suffered by paediatric survivors of the Manchester Arena bomb blast. It highlights the demands on a trauma unit following such an event

Spinal fractures are common following underbody blast. Most injuries occur at the thoracolumbar junction, and fracture patterns suggest the spine is flexed at the moment of injury. However, current mechanistic descriptions of vertebral fractures are based on low energy injuries, and there is no evidence to correlate fracture pattern with posture at the loading rates seen in blast injury. The T12-L1 segment of 4 human spines was dissected to preserve the paraspinal ligaments and potted in polymethylmecrylate. The specimens were impacted with a 14 kg mass at 3.5m/s in a drop tower; two specimens were impacted in neutral posture, one in flexion, and one in extension. A load cell measured the load history. CT scans and dissection identified the injury patterns. Each specimen sustained a burst fracture. The neutral specimens demonstrated superior burst fractures, the flexed specimen demonstrated a superior burst fracture with significant anterior involvement, and the extended specimen showed a posterior vertebral body burst fracture. At high loading rates, the posture of the spine at the moment of injury appears to affect the resulting fracture. This supports understanding the behaviour of the spine in blast injury and will allow improved mitigation system design in the future

The interaction of a blast wave with the thorax produces primary pulmonary blast injury by releasing energy at biological interfaces of differing acoustic impedance. This process is known as coupling. It was hypothesised that protective armour designed on the basis of an acoustic decoupler, may modulate the effect of thoracic blast. Anaesthetised, spontaneously breathing male pigs (n=18) were allocated into two equal groups and exposed to whole body blast in free field conditions. All animals were provided with Kevlar® protection, but in addition animals in group 2 were provided with protective thoracic armour. Blood gas analysis was performed prior to and up to 1 h post-blast. The animals were killed at 1 h post-blast and a post-mortem carried out. Severity of lung injury, called the quotient of injury (QI) was calculated by comparing masses of injured lung with standardised uninjured lung masses. All procedures complied with the Animals (Scientific Procedures) Act 1986. In group 1, PaO2 was reduced from a pre-blast mean of 9.7 kPa to a post-blast mean of 6.6 kPa, whereas in group 2 PaO2 fell from a pre-blast mean of 10.5 kPa to a post-blast mean of 8.3 kPa. The difference between the groups was statistically significant (p< 0.05). The mean QI in group 1 was 1.7 compared to a group 2 mean of 1.12, indicating severe injury in the unprotected animals (p< 0.01). Decoupling protective thoracic armour ameliorated the effects of thoracic blast in this animal model. This will lead to the development of personal protective thoracic armour for frontline servicemen

Purpose: The purpose of this study is to evaluate the results of the treatment by severe blast injuries to limbs. Materials and methods: Twenty-seven patients after blast injuries were treated. There were 13 patients with tibial fractures, 7 fractures of the femur, 4 – fractures of the humerus and 3 with fractures of the forearm bones. According to Gustilo all fractures were open grade 3B and 3C. According to MESS a median value was 4,7 points (range 3 – 7). Six had on admission vascular injuries, and 12 had peripheral nerve injuries. There was other major organ trauma in 55,5% of patients. On admission, the fractured bones are realigned and stabilized with an AO tubular external fixation frame followed by immediate thorough soft tissue debridement, vascular reconstruction. In patients with peri-articular fractures temporary trans-articular bridging was needed. After 5 to 7 days or when wound condition permits, delayed primary sutures, the application of skin grafts or free tissue flaps are performed. At this stage, the tubular fixator is exchanged for a circular frame that allows stability, sufficient for full weight bearing by minimal invasive fixation and meticulous attention to freeing the previously bridged joints. Hybrid frames allows combination of advantages of each type of external fixators. Closed reduction of fractures was performed in most patients by ligamentotaxis and use thin wires with olives. Fixation in elastic frame combined with cyclic loading provide favorable biomechanical environment for fracture healing. In patients with high-energy “floating elbow” injuries the hybrid circular devices of the humerus and forearm were connected by hinges to allow immediate elbow joint movements. The separate fixation of the forearm bones was performed to allow early pronation/supination motions. Results: In all patients the external fixation was the definitive treatment. Fracture union was achieved at median time of 240 days (range 90 – 546). Throughout the period of fracture healing the patients were fully ambulatory, living at home. In three patients with bilateral highly complex blast injuries of lower extremities, where one limb had to be amputated, the Ilizarov device for severely injured contralateral limb provided the conditions necessary for early prosthetic fitting. There was one non-union and one patient developed chronic osteomyelitis treated by serial debridement and sequestrectomies. Conclusions: Based on this experience, we suggest that the stabilization in ring frame with radical debridement and early tissue transfer provides fracture healing and good functional results in extensive compound blast injuries of the extremities even in limbs categorized as high risk

A retrospective analysis of all paediatric patients admitted to Camp Bastion Role 3 between June 2006 and March 2013 was conducted from the UK trauma database. Patient demographics, mechanism of injury, anatomical distribution of injury and treatment are described. Two hundred and ninety eight children were admitted, 225 males with a median age of 9 years old. The highest number of cases (78) was recorded in 2011. Overall there were 55 fatalities (85.6% male). Most injuries were by IED (68% of cases) with 74% requiring operative intervention. Seventy-four percent of casualties had three or more anatomical regional injuries. Whilst the most commonly injured region was the lower limb (78%), head injuries were seen in 41%, abdominal injuries in 48% and thorax injuries in 44%. Debridement (including amputations) (59.4%) and laparotomy (30.6%) were the commonest operations performed. Sixty percent of cases were in theatre within one hour of arrival. Amongst survivors the mean ISS score was 17 and amongst fatalities 43; NISS 22 and 51; RTS 5.45 and 2.91. Paediatric blast injuries represent a significant burden to medical facilities in contemporary conflict. Whilst limb injuries predominate, the proportion of head and torso injuries is higher than seen in adult blast injuries

Purpose: Blast injury of the hand generally occurs during manipulations of unstable explosives. The explosion greatly damages the first commissure. The aim of this study was to define a classification system useful for establishing therapeutic strategy. Material and methods: From 1988 to 2002, we treated eight patients (nine hands, five dominant) with blast injury of the hand. Mean age was 24 years. Five hands were injured during manipulation of firecrackers and four during manipulation of munitions. The thumb was amputated on five hands, including three cases of index or medius amputation. Thumb revascularisation was successful in only one case. Two proximal thumb amputations were treated by twisted toe transfer. For one of these patients, the transfer was prepared by translocation of M2 on M1 using an inguinal flap. Two patients required a composite osteocutaneous reconstruction of M1 using the index as the bone source. In one final patient, lesions were limited to soft tissues. Discussion: Blast injured hands present several types of lesions: extensive soft tissue damage, diffuse vessel damage making revascularisation difficult or impossible, combined thenar and joint lesions leading to secondary closure of the first commissure. We distinguished three stages. Stage 1 involves only muscle and skin damage. After opening the first commissure with M1-M2 pinning, cover is achieved with a posterior interosseous flap or a skin graft. Stage 2 involves osteoarticular damage. Bone loss of M1 and P1 is often associated with dislocation. Bone reconstruction is often achieved using the distally amputated or greatly damaged thumb. Stage 3 involves amputation or devascularisation of the thumb. Reconstruction of the thumb is particularly difficult in these cases. If the amputation is distal beyond MP, M1 lengthening or classical toe transfer can be used. If the amputation is proximal, prior M1 reconstruction is required with a skin envelope using M2 fashioned with an interosseous or inguinal flap, followed by twisted toe transfer of the second toe. Stage 3 translocations are difficult because of the often damaged index and scar formation

Advances in military surgery have led to significant numbers of soldiers surviving with bilateral above knee amputations. Despite advances in prosthetic design and high quality rehabilitation not all amputees succesfully ambulate. Five patients (10 stumps) with persisting socket fit issues were selected for osseointegration (OI) using a transcutaneous prosthesis with press-fit fixation in the residual femur. Prior to surgery all five were primarily/exclusively wheelchair users. Follow up was from 7 to 25 months (mean 12.2). There were no deaths, episodes of sepsis or osteomyelitis. There was one proximal femoral fracture secondary to a fall. One stump required soft tissue refashioning. Cellulitis needing oral antibiotics occurred in four cases. Functional improvement occurred in all cases with all currently primarily prosthetic users, the majority all day users. Three patients are still completing rehabilitation. Six minute walk tests (SMWT) improved by a mean of 20%. Three are now graded mobility SIGAM F (normal gait) and two SIGAM D-b (limited terrain; with one stick). This cohort suggests that OI may have a role in the treatment of military blast amputees. A larger scale clinical evaluation is planned in the UK blast related amputee population to further establish the benefits and risks of this technique

Recent advances in combat casualty care have enabled survival following battlefield injuries that would have been lethal in past conflicts. While some injuries remain beyond our current capability to treat, they have the potential to be future ‘unexpected’ survivors. The greatest threat to deployed coalition troops currently and for the foreseeable future is the improvised explosive device (IED) Therefore, the aim of this study was to conduct an analysis of causes of death and injury patterns in recent explosive blast fatalities in order to focus research and mitigation strategies, to further improve survival rates. Since November 2007, UK Armed Forces personnel killed whilst deployed on combat operations undergo both a post mortem computed tomography (PMCT) scan and an autopsy. With the permission of the coroners, we analysed casualties with PMCTs between November 2007 and July 2010. Injury data were analysed by a pathology-forensic radiology-orthopaedic multidisciplinary team. Cause of death was attributed to the injuries with the highest AIS scores contributing to the NISS score. Injuries with an AIS < 4 were excluded. During the study period 227 PMCT scans were performed; 211 were suitable for inclusion, containing 145 fatalities due to explosive blast from IEDs. These formed the study group. 24 cases had such severe injuries (disruptions) that further study was inappropriate. Of the remaining 121, 79 were dismounted, and 42 were mounted (in vehicles). Leading causes of death were head CNS injury (47.6%), followed by intra-cavity haemorrhage (21.7%) in the mounted group, and extremity haemorrhage (42.6%), junctional haemorrhage (22.2%) and head CNS injury (18.7%) in the dismounted group. The severity of head trauma in both mounted and dismounted IED fatalites would indicate that prevention and mitigation of these injuries is likely to be the most effective strategy to decrease their resultant mortality. Two thirds of dismounted fatalities have haemorrhage implicated as a cause of death that may have been amenable to prehospital treatment strategies. One fifth of mounted fatalites have haemorrhagic trauma which currently could only be addressed surgically. Maintaining the drive to improve all haemostatic techniques for combat casualties from point of wounding to definitive surgical proximal control alongside development and application of novel haemostatics could yield a significant survival benefit

Aim/Purpose. Review our unique experience in the management of 29 consecutive casualties who survived open pelvic fractures following a blast mechanism. Methods and Results. Retrospective study utilising a prospectively collected combat trauma registry. Records of UK Service Personnel sustaining open pelvic fractures from an explosion from Aug 2008 – Aug 2010 identified. Casualties who survived to be repatriated to the Royal Centre for Defence Medicine, University Hospital Birmingham were selected for further study. The median New Injury Severity Score (NISS) was 41. Mean blood requirement in the first 24 hours was 60.3 units. In addition to their orthopaedic injury, 6 (21%) had an associated vascular injury, 7(24%) had a bowel injury, 11 (38%) had a genital injury and 7(24%) had a bladder injury. 8 (28%) fractures were managed definitively with external fixation, and 7 (24%) fractures required internal fixation. Of those patients who underwent internal fixation, 5 (57%) required removal of metalwork for infection. Faecal diversion was performed on 9 (31%) casualties. Median length of stay was 70.5 days, and mean total operative time was 29.6 hours. At a mean 20.3 months follow-up, 24 (83%) were able to ambulate, and 26 (90%) had clinical and radiological evidence of pelvic ring stability. Conclusion. As a result of the “Global War on Terror” injuries that were previously confined exclusively to conflict areas can now occur anywhere in the form of terrorist attacks. Given the nature of the soft tissue injury, we would advocate an approach of predominantly external fixation in the management of these fractures. With the advent of emerging wound and faecal management techniques, we do not believe that faecal diversion is mandated in all cases

The aim of this study is to review our unique experience in the management of 29 consecutive casualties who survived open pelvic fractures following a blast mechanism, in order to determine the injury pattern, clinical management and outcome of these devastating injuries. All patients were serving soldiers who were injured whilst on operations in Afghanistan. The median New Injury Severity Score (NISS) was 41. Mean blood requirement in the 1. st. 24 hours was 60.3 units. In addition to their orthopaedic injury, 6 (21%) had an associated vascular injury, 7(24%) had a bowel injury, 11 (38%) had a genital injury and 7(24%) had a bladder injury. 8 (28%) fractures were managed definitively with external fixation, and 7 (24%) fractures required ORIF. Of those patients who underwent ORIF, 4 (57%) required removal of metalwork for infection. Faecal diversion was performed on 9 (31%) casualties. Median length of stay was 70.2 days, and mean total operative time was 29.6 hours. At a mean 20.3 months follow-up, 24 (83%) were able to ambulate, and 26 (90%) had clinical and radiological evidence of pelvic ring stability. The “Global War on Terror” has resulted in incidents that were previously confined exclusively to conflict areas can now occur anywhere, and surgeons who are involved in trauma care may be required to manage similar injuries from terrorist attacks. Our study clearly demonstrates that the management of this injury pattern is extremely resource intensive with the need for significant multi-disciplinary input. Given the nature of the soft tissue injury, we would advocate an approach of minimal internal fixation in the management of these fractures. With the advent of emerging wound and faecal management techniques, we do not believe that faecal diversion is mandated in all cases

Traumatic amputations (TAs) are amongst the most significant orthopaedic sequelae following IED strikes. Biomechanically, longer residual limb length confers better function. However, post-trauma definitive through knee amputation (TKA) remains controversial. UK military casualties sustaining ≥1 major TA, 01/08/2008–01/08/2010 were identified using the UK JTTR and post mortem CT databases. All through- and below-knee TAs were termed ‘potential TKAs’ (p-TKAs); hypothetical candidates for definitive TKA. We hypothesised that traumatic TKAs were more common than previously reported (4.5% of lower limb TAs) and a significant cohort of blast injuries exist suitable for definitive TKA. 146 cases (75 survivors, 71 fatalities) sustained 271 TAs (235 lower limb). TKA rate was 34/235 (14.2%). 63/130 survivor TAs and 66/140 fatality TAs merited analysis as p-TKAs. Detailed pathoanatomy was only available for fatality p-TKAs, for whom definitive TKA would have been proximal to the zone of injury (ZOI) in only 3/66 cases. Blast-mediated traumatic TKAs are significantly more common than previously reported (p=0.0118). Most lower limb TAs are skeletally amenable to definitive TKA. Maximising stump length for function incurs the risks of definitive amputation within the original ZOI (including infection and heterotopic ossification) but proximal extent of blast soft tissue injury commonly makes this unavoidable

Various injury severity scores exist for trauma; it is known that they do not correlate accurately to military injuries. A promising anatomical scoring system for blast pelvic and perineal injury led to the development of an improved scoring system using machine-learning techniques. An unbiased genetic algorithm selected optimal anatomical and physiological parameters from 118 military cases. A Naïve Bayesian (NB) model was built using the proposed parameters to predict the probability of survival. Ten-fold cross validation was employed to evaluate its performance. Our model significantly out-performed Injury Severity Score (ISS), Trauma ISS, New ISS and the Revised Trauma Score in virtually all areas; Positive Predictive Value 0.8941, Specificity 0.9027, Accuracy 0.9056 and Area Under Curve 0.9059. A two-sample t-test showed that the predictive performance of the proposed scoring system was significantly better than the other systems (p<0.001). With limited resources and the simplest of Bayesian methodologies we have demonstrated that the Naïve Bayesian model performed significantly better in virtually all areas assessed by current scoring systems used for trauma. This is encouraging and highlights that more can be done to improve trauma systems not only for the military, but also in civilian trauma

Heterotopic ossification (HO) is perhaps the single most significant obstacle to independence, functional mobility, and return to duty for combat-injured veterans of Operation Enduring Freedom and Operation Iraqi Freedom. Recent research into the cause(s) of HO has been driven by a markedly higher prevalence seen in these wounded warriors than encountered in previous wars or following civilian trauma. To that end, research in both civilian and military laboratories continues to shed light onto the complex mechanisms behind HO formation, including systemic and wound specific factors, cell lineage, and neurogenic inflammation. Of particular interest, non-invasive in vivo testing using Raman spectroscopy may become a feasible modality for early detection, and a wound-specific model designed to detect the early gene transcript signatures associated with HO is being tested. Through a combined effort, the goals of early detection, risk stratification, and development of novel systemic and local prophylaxis may soon be attainable.

Anti-vehicle mines (AV) and Improvised Explosive Devices (IEDs) remain the most prevalent threat to Coalition troops operating in Iraq and Afghanistan. Detonation of these devices results in 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.

From Jan 2006 – Dec 2008, utilising a prospectively collected trauma registry (Joint Theatre Trauma Registry, JTTR), 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 (NISS), and associated injuries were recorded. In addition, the pattern of calcaneal fracture, the method of stabilisation, local complications and need for amputation was noted. Functional recovery was related to the ability of the casualty to return to military duties.

Forty calcaneal fractures (30 patients) were identified in this study. Mean follow-up was 33.2 months. The median NISS 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 UK. 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 any military duty.

Calcaneal injuries following under-vehicle explosions are commonly associated with significant polytrauma, of which the lower limb injury is the most severe. Spinal injuries were frequently associated with this injury pattern and it is recommended that radiological evaluation of the spine be performed on all patients presenting with calcaneal injuries from this injury mechanism. The severity of the hindfoot injury witnessed is reflected by the high infection rate and amputation rate seen in this cohort of patients. Given the high physical demands of a young, active military population, only a small proportion of casualties were able to return to pre-injury duties. We believe that the key to the reduction in the injury burden to the soldier lies in the primary prevention of this injury. Work is currently on going to develop experimental and numerical models of this injury in order to drive future mitigation strategies.