Developing an exercise intervention to improve bone mineral density in traumatic amputees: protocol for a Delphi study

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.

Association Between Combat-Related Traumatic Injury and Skeletal Health: Bone Mineral Density Loss Is Localized and Correlates With Altered Loading in Amputees: the Armed Services Trauma Rehabilitation Outcome (ADVANCE) Study

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.

Mechanical assessment of proprietary and improvised pelvic binders for use in the prehospital environment

INTRODUCTION

Pelvic fractures often result from high-energy trauma and are associated with a 10% mortality rate and significant morbidity. Pelvic binders are applied in suspected pelvic injury to stabilise fractured bone, decrease bleeding and potentiate tamponade. A binder must hold the pelvis with sufficient force for this effect to be achieved. This study aims to quantify the ability of proprietary and improvised pelvic binders to hold a target tensile force over time.

METHODS

The ability of three proprietary and three improvised binders to hold a binding force for 2 hours was tested. A uniaxial materials testing machine was used to tension each binder to 150 N and then hold the displacement for 2 hours; the drop in tension over time was recorded for each binder. The ability to hold tension above 130 N after 2 hours was set as the metric of binder performance.

RESULTS

The median tension at 2 hours was above 130 N for the SAM Pelvic Sling II and T-POD Pelvic Stabilisation Device and was below 130 N for the Prometheus Pelvic Splint, field-expedient pelvic splint (FES) and the Personal Clothing System-Multi-Terrain Pattern Combat Trousers binders. The tension in the improvised FES after 2 hours was approximately at the target 130 N; however, in 40% of the tests, it held above 130 N.

CONCLUSIONS

Binders varied in their ability to maintain sufficient tension to treat a pelvic fracture over the 2-hour testing period. The FES performed well under our testing regime; with relatively low cost and weight, it represents a good alternative to proprietary binders for the austere environment.

Interpreting perimortem blast trauma from skeletal remains: Complications and considerations

Blast trauma results from highly variable events that can lead to similar effects in the skeleton. Clinical literature, which largely focuses on soft tissue, provides limited efficacy for interpreting fully skeletonized cases. Interpretation of skeletal blast trauma is hampered by the low number of fully skeletonized case studies and experimental replication studies, which mainly use nonhuman proxies. The purpose of this study is to discuss fracture patterns on two individuals from WWII as a means to better understand and identify fracture patterns associated with blast trauma. Existing clinical and anthropological criteria are reviewed and applied to two World War II cases, both presumed to exhibit blast trauma based on historical contexts. These case studies exhibit combinations of complicated and extensive signs of blunt-force and projectile trauma, reflecting the diversity of skeletal trauma resulting from blast-related events. This analysis emphasizes the arguably impossible task of establishing a diagnosis based on the available literature and lack of prior knowledge about specific losses. Ultimately, analysts must consider the totality of skeletal trauma, combining biomechanical theory and relevant clinical and anthropological literature to arrive at useful yet defensible assessments of trauma. However, refined criteria and additional studies are needed to assess complicated trauma from blast-related events in anthropological contexts.

American Academy of Orthopaedic Surgeons Clinical Practice Guideline Summary for Limb Salvage or Early Amputation

Clinical Practice Guideline for Limb Salvage or Early Amputation is based on a systematic review of current scientific and clinical research. The purpose of this clinical practice guideline is to address treatment for severe lower limb trauma below the distal femur by either amputation or limb salvage by providing evidence-based recommendations for key decisions that affect the management of patients with lower extremity trauma. This guideline contains 11 recommendations to evaluate the decision factors important for limb salvage versus early amputation. In addition, the work group highlighted the need for better research in the treatment and the shared decision making process of high-energy lower extremity trauma.

The Injury Mechanism of Traumatic Amputation

Traumatic amputation has been one of the most defining injuries associated with explosive devices. An understanding of the mechanism of injury is essential in order to reduce its incidence and devastating consequences to the individual and their support network. In this study, traumatic amputation is reproduced using high-velocity environmental debris in an animal cadaveric model. The study findings are combined with previous work to describe fully the mechanism of injury as follows. The shock wave impacts with the casualty, followed by energised projectiles (environmental debris or fragmentation) carried by the blast. These cause skin and soft tissue injury, followed by skeletal trauma which compounds to produce segmental and multifragmental fractures. A critical injury point is reached, whereby the underlying integrity of both skeletal and soft tissues of the limb has been compromised. The blast wind that follows these energised projectiles completes the amputation at the level of the disruption, and traumatic amputation occurs. These findings produce a shift in the understanding of traumatic amputation due to blast from a mechanism predominately thought mediated by primary and tertiary blast, to now include secondary blast mechanisms, and inform change for mitigative strategies.

Antibiotic Practice Patterns for Extremity Wound Infections among Blast-Injured Subjects

INTRODUCTION

We examined antibiotic management of combat-related extremity wound infections (CEWI) among wounded U.S. military personnel (2009-2012).

METHODS

Patients were included if they sustained blast injuries, resulting in ≥1 open extremity wound, were admitted to participating U.S. hospitals, developed a CEWI (osteomyelitis or deep soft-tissue infections) within 30 days post-injury, and received ≥3 days of relevant antibiotic (s) for treatment.

RESULTS

Among 267 patients, 133 (50%) had only a CEWI, while 134 (50%) had a CEWI plus concomitant non-extremity infection. In the pre-diagnosis period (4-10 days prior to CEWI diagnosis), 95 (36%) patients started a new antibiotic with 28% of patients receiving ≥2 antibiotics. During CEWI diagnosis week (±3 days of diagnosis), 209 (78%) patients started a new antibiotic (71% with ≥2 antibiotics). In the week following diagnosis (4-10 days after CEWI diagnosis), 121 (45%) patients started a new antibiotic with 39% receiving ≥2 antibiotics. Restricting to ±7 days of CEWI diagnosis, patients commonly received two (35%) or three (27%) antibiotics with frequent combinations involving carbapenem, vancomycin, and fluoroquinolones.

CONCLUSIONS

Substantial variation in antibiotic prescribing patterns related to CEWIs warrants development of combat-related clinical practice guidelines beyond infection prevention, to include strategies to reduce the use of unnecessary antibiotics and improve stewardship.

Restricting Lower Limb Flail is Key to Preventing Fatal Pelvic Blast Injury

Pelvic vascular injury in the casualty of an explosive insult is a principal risk factor for increased mortality. The mechanism of injury has not previously been investigated in a physical model. In this study, a small-animal model of pelvic blast injury with a shock-tube mediated blast wave was utilised and showed that lower limb flail is necessary for an unstable pelvic fracture with vascular injury to occur. One hundred and seventy-three cadaveric mice underwent shock-tube blast testing and subsequent injury analysis. Increasingly displaced pelvic fractures and an increase in the incidence of pelvic vascular injury were seen with increasing lower limb flail; the 50% risk of vascular injury was 66° of lower limb flail out from the midline (95% confidence intervals 59°–75°). Pre-blast surgical amputation at the hip or knee showed the thigh was essential to result in pelvic displacement whilst the leg was not. These findings, corroborated by clinical data, bring a paradigm shift in our understanding of the mechanism of blast injury. Restriction of lower limb flail in the human, through personal protective equipment, has the potential to mitigate the effects of pelvic blast injury.

Environment at the time of injury determines injury patterns in pelvic blast

The use of explosives by terrorists, or during armed conflict, remains a major global threat. Increasingly, these events occur in the civilian domain, and can potentially lead to injury and loss of life, on a very large scale. The environment at the time of detonation is known to result in different injury patterns in casualties exposed to blast, which is highly relevant to injury mitigation analyses. We describe differences in pelvic injury patterns in relation to different environments, from casualties that presented to the deployed UK military hospitals in Iraq and Afghanistan. A casualty on foot when injured typically sustains an unstable pelvic fracture pattern, which is commonly the cause of death. These casualties die from blood loss, meaning treatment in these should focus on early pelvic haemorrhage control. In contrast, casualties injured in vehicle present a different pattern, possibly caused by direct loading via the seat, which does not result in pelvic instability. Fatalities in this cohort are from injuries to other body regions, in particular the head and the torso and who may require urgent neurosurgery or thoracotomy as life-saving interventions. A different strategy is therefore required for mounted and dismounted casualties in order to increase survivors.