Characterization of extremity wounds in Operation Iraqi Freedom and Operation Enduring Freedom

Combined regenerative rehabilitation improves recovery following volumetric muscle loss injury in a rat model

Volumetric muscle loss (VML) injury causes irreversible deficits in muscle mass and function, often resulting in permanent disability. The current standard of care is physical therapy, but it is limited in mitigating functional deficits. We have previously optimized a rehabilitation technique using electrically stimulated eccentric contraction training (EST) that improved muscle mass, strength, and size in VML-injured rats. A biosponge scaffold composed of extracellular matrix proteins has previously enhanced muscle function postVML. This study aimed to determine whether combining a regenerative therapy (i.e., biosponge) with a novel rehabilitation technique (i.e., EST) could enhance recovery in a rat model of VML. A VML defect was created by removing ~20% of muscle mass from the tibialis anterior muscle in adult male Lewis rats. Experimental groups included VML-injured rats treated with biosponge with EST or biosponge alone (n = 6/group). EST was implemented 2 weeks postinjury at 150 Hz and was continued for 4 weeks. A linear increase in eccentric torque over 4 weeks showed the adaptability of the VML-injured muscle to EST. Combining biosponge with EST improved peak isometric torque by ~52% compared with biosponge treatment alone at 6 weeks postinjury. Application of EST increased MyoD gene expression and the percentage of large (>2000 μm2) type 2B myofibers but reduced fibrotic tissue deposition in VML-injured muscles. Together, these changes may provide the basis for improved torque production. This study demonstrates the potential for combined regenerative and rehabilitative therapy to improve muscle recovery following VML.

Invasive fungal infections in wars, following explosives and natural disasters: A narrative review

Infections are well-known complications in patients following traumatic injuries, frequently leading to high morbidity and mortality. In particular, trauma occurring in disaster settings, both natural and man-made, such as armed conflicts and explosives detonation, results in challenging medical conditions that impede the best management practices. The incidence of invasive fungal infections (IFI) is increasing in trauma patients who lack the typical risk factors like an immune compromised state or others. This narrative review will focus on IFI as a direct complication after natural disasters, wars, and man-made mass destruction with a summary of the available evidence about the epidemiology, clinical manifestations, risk factors, microbiology, and proper management. In this setting, the clinical manifestations of IFI may include skin and soft tissue infections, osteomyelitis, visceral infections, and pneumonia. IFI should be considered in the war inflicted patients who are exposed to unsterile environments or have wounds contaminated with soil and decaying organic matter.

Contemporary History of Spine Fractures Following Deck-Slap Injury: From Deck Blast During World War II Naval Battles to Axial Trauma During Touristic Speedboat Sea Cruise in 21st Century

In large-scale naval battles during World War II, sailors sometimes sustained serious lower limb injuries when explosion blast of sea mines was transmitted from underneath through the metal deck of the ships. Some of these sailors were thrown in the air due to the blast and sustained axial trauma of the spine when they landed on the hard deck, which was thus called a deck slap by Captain Joseph Barr in 1946, among others. Nowadays, this peculiar mechanism has shifted to the civilian setting. Tourists unaware of the danger may sustain spine compression fractures when they sit at the bow of speed boats while underway on a calm sea. When the craft unexpectedly crosses the wake of another ship, tourists are thrown a few feet in the air before suffering a hard landing on their buttocks. This historical vignette is presented as a preventive message to help to reduce this poorly known yet avoidable "summer wave of vertebral fractures."

Development of a multidimensional military readiness assessment

There is a need to be able to accurately evaluate whether an injured service member is able to return to duty. An effective assessment would challenge and measures physical and cognitive performance in a military-relevant context. Current assessments are lacking in one or more of these aspects. The simulation and data capture abilities of virtual reality systems are promising for use as the basis of multidimensional assessments. The team has previously developed a military-specific assessment in the Computer Assisted Rehabilitation Environment (CAREN) called the Readiness Evaluation During simulated Dismounted Operations (REDOp). Due to notable limitations in the original assessment, we have developed the next iteration, REDOp2. The assessment is able to challenge and measure a broader range of physical and cognitive performance domains in a more streamlined fashion. While limited to facilities with a CAREN, REDOp2 has the potential to provide an effective tool for highly trained and experienced wounded service members that require thorough assessment prior to returning to duty to ensure the safety of the team and mission. This methods paper describes the specific limitations in REDOp, how they were addressed in REDOp2, and suggested next steps to prepare the assessment for implementation.

Mental and Physical Health-Related Quality of Life Following Military Polytrauma

INTRODUCTION

The long-term impact of deployment-related trauma on mental and physical health-related quality of life (HRQoL) among military personnel is not well understood. We describe the mental and physical HRQoL among military personnel following deployment-related polytrauma after their discharge from the hospital and examine factors associated with HRQoL and longitudinal trends.

MATERIALS AND METHODS

The U.S. military personnel with battlefield-related trauma enrolled in the Trauma Infectious Diseases Outcomes Study were surveyed using SF-8 Health Surveys at 1 month post-discharge (baseline) and at follow-up intervals over 2 years. Inclusion in the longitudinal analysis required baseline SF-8 plus responses during early (3 and/or 6 months) and later follow-up periods (12, 18, and/or 24 months). Associations of demographics, injury characteristics, and hospitalization with baseline SF-8 scores and longitudinal changes in SF-8 scores during follow-up were examined. Survey responses were used to calculate the Mental Component Summary score (MCS) and the Physical Component Summary score (PCS). The MCS focuses on vitality, mental health, social functioning, and daily activity limitations, whereas PCS is related to general health, bodily pain, physical functioning, and physical activity limitations. Longitudinal trends in SF-8 scores were assessed using chi-square tests by comparing the median score at each timepoint to the median 1-month (baseline) score, as well as comparing follow-up scores to the immediately prior timepoint (e.g., 6 months vs. 3 months). Associations with the 1-month baseline SF-8 scores were assessed using generalized linear regression modeling and associations with longitudinal changes in SF-8 were examined using generalized linear regression modeling with repeated measures.

RESULTS

Among 781 enrollees, lower baseline SF-8 total scores and PCS were associated with spinal and lower extremity injuries (P < .001) in the multivariate analyses, whereas lower baseline MCS was associated with head/face/neck injuries (P < .001). Higher baseline SF-8 total was associated with having an amputation (P = .009), and lower baseline SF-8 total was also associated with sustaining a traumatic brain injury (TBI; P = .042). Among 524 enrollees with longitudinal follow-up, SF-8 scores increased, driven by increased PCS and offset by small MCS decreases. Upward SF-8 total score and PCS trends were associated with time post-hospital discharge and limb amputation (any) in the multivariate analyses (P < .05), whereas downward trends were independently associated with spinal injury and developing any post-discharge infection (P ≤ .001). Patients with lower extremity injuries had lower-magnitude improvements in PCS over time compared to those without lower extremity injuries (P < .001). Upward MCS trend was associated with higher injury severity (P = .003) in the multivariate analyses, whereas downward trends were independently associated with having a TBI (P < .001), time post-hospital discharge (P < .001), and occurrence of post-discharge infections (P = .002).

CONCLUSIONS

Overall, HRQoL increased during the 2-year follow-up period, driven by PCS improvement. Increasing HRQoL was associated with time since hospital discharge and limb amputation, whereas a downward trend in HRQoL was associated with spinal injury and post-discharge infection. The longitudinal decline in MCS, driven by TBI occurrence, time since hospital discharge, and developing post-discharge infections, emphasizes the importance of longitudinal mental health care in this population.

The Scope and Distribution of Upper Extremity Nerve Injuries Associated With Combat-Related Extremity Limb Salvage

PURPOSE

Chronic pain and functional limitations secondary to nerve injuries are a major barrier to optimal recovery for patients following high-energy extremity trauma. Given the associated skeletal and soft tissue management challenges in the polytraumatized patient, concomitant nerve injuries may be overlooked or managed in delayed fashion. Whereas previous literature has reported rates of peripheral nerve injuries at <10% in the setting of high-energy extremity trauma, in our experience, the incidence of these injuries has been much higher. Thus, we sought to define the incidence, pain sequelae, and functional outcomes following upper extremity peripheral nerve injuries in the combat-related limb salvage population.

METHODS

We performed a retrospective review of all patients who underwent limb salvage procedures to include flap coverage for combat-related upper extremity trauma at a single institution between January 2011 and January 2020. We collected data on patient demographics; perioperative complications; location of nerve injuries; surgical interventions; chronic pain; and subjective, patient-reported functional limitations.

RESULTS

A total of 45 patients underwent flap procedures on 49 upper extremities following combat-related trauma. All patients were male with a median age of 27 years, and 96% (n = 47) of injuries were sustained from a blast mechanism. Thirty-three of the 49 extremities (67%) sustained associated nerve injuries. The most commonly injured nerve was the ulnar (51%), followed by median (30%) and radial/posterior interosseous (19%). Of the 33 extremities with nerve injuries, 18 (55%) underwent surgical intervention. Nerve repair/reconstruction was the most common procedure (67%), followed by targeted muscle reinnervation (TMR, 17%). Chronic pain and functional limitation were common following nerve injury.

CONCLUSIONS

Upper extremity peripheral nerve injury is common following high-energy combat-related trauma with high rates of chronic pain and functional limitations. Surgeons performing limb salvage procedures to include flap coverage should anticipate associated peripheral nerve injuries and be prepared to repair or reconstruct the injured nerves, when feasible.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Computational assessment of leg response to extreme loadings using a detailed finite element model

This study focuses on evaluating the response of the Total Human Model for Safety™ lower extremity finite element model under blast loading. Biofidelity of the lower extremity model was evaluated against experiments with impact loading equivalent to underbody blast. The model response was found to match well with the experimental data for the average impactor speeds of 7 and 9.3 m/s resulting in an overall correlation and analysis rating of 0.86 and 0.82, respectively. The model response was then used to investigate response for antipersonnel mine explosion where the numerical setup consists of a charge mass of 40 g trinitrotoluene placed at a depth of 50 mm below the heel. The explosion was modeled using Multi Material-Arbitrary Lagrangian Eulerian method. The model was subjected to the graded input in terms of variation in standoff distance and mass of explosive to investigate the sensitivity of the model. The model found sensitive to the threat definition and predicted an increase of 110% in peak fluid-structure interaction force with 20% reduction in its time to peak and 29% increase in peak calcaneus axial force with a reduction of 33% in its time to peak when explosive mass varied from 40 g to 100 g. The location of the explosive below the foot was discovered to have significant effect on the injury pattern in near-field explosion. A comparative study suggested that the model predicted similar response and damage pattern compared to experimental data.

Nine years of surgical activity in the deployed French military role 2 medical treatment facility in Mali

INTRODUCTION

In January 2013, France launched a military operation in Mali, which ended in August 2022. This study aimed to analyse the global activity performed by a surgical team within the role 2 medical treatment facility (MTF) deployed in Gao during this period, in order to adapt medical battlefield support and combat casualty care teaching.

METHODS

A retrospective study was conducted using the French surgical database OpEX (French Military Health Service) from January 2013 to August 2022. All patients operated on were included.

RESULTS

During this period, 1298 patients with a median age of 29 (range: 23-38) years were included. Among them, 229 (17.6%) underwent a combat-related trauma surgery (CRTS), 234 (18.0%) underwent a non-CRTS, 167 (12.9%) underwent a non-trauma-related surgery and 668 (51.5%) underwent a scheduled surgery in the context of medical supply to the population.Among the CRTS group, 195 (85.2%) patients underwent an orthopaedic procedure, 73 (31.8%) required a general surgery. Finally, 15 (6.6%) wounded required a specialised surgery.

CONCLUSIONS

In line with the activity described in the role 2 MTF deployed in other contemporary asymmetric conflicts, this activity is moderate, especially if only combat-related injuries are considered; medical support to the population occupied most of the surgical activity. For CRTS, most of the traumas are limb traumas. Other traumas are composed of various lesions, which are often life-threatening. This fact imposes the presence of an orthopaedic surgeon with the appropriate equipment, as well as a general surgeon with a wide range of skills, in asymmetric conflicts.

Extremity injuries in the Sahelian conflict: lessons learned from a French Forward Surgical Team deployed in Gao, Mali

PURPOSE

This study aimed to analyse extremity combat-related injuries (CRIs) and non-combat related injuries (NCRIs) treated in the French Forward Surgical Team deployed in Gao, Mali.

PATIENTS AND METHODS

A retrospective study was conducted using the French surgical database OpEX (French Military Health Service) from January 2013 to August 2022. Patients operated on for an extremity injury less than one month old were included.

RESULTS

During this period, 418 patients with a median age of 28 years [range 23-31 years] were included and totalized 525 extremity injuries. Among them, 190 (45.5%) sustained CRIs and 218 (54.5%) sustained NCRIs. Multiple upper extremity injuries and associated injuries were significantly more common in the CRIs group. The majority of NCRIs involved the hand. Debridement was the most common procedure in both groups. External fixation, primary amputation, debridement, delayed primary closure, vascular repair and fasciotomy were significantly predominant in the CRIs group. Internal fracture fixation and reduction under anaesthesia were statistically more frequent in the NCRIs group. The overall number of procedures and the overall number of surgical episodes were significantly higher in the CRIs group.

CONCLUSION

CRIs were the most severe injuries and did not involve the upper and lower limbs separately. A sequential management was required with application of damage control orthopaedics followed by several procedures for reconstruction. NCRIs were predominant and mostly involved the hand among the French soldiers. This review supports the fact that any deployed orthopaedic surgeon should be trained in basic hand surgery and preferably have microsurgical skills. The management of local patients requires the execution of reconstructive surgery and therefore imposes the presence of adequate equipment.

A Quantitative and Qualitative Literature Analysis of the Orthopedic Surgeons' Experience: Reflecting on 20 Years in the Global War on Terror

INTRODUCTION

After over 20 years of war in the Middle East, orthopedic injuries have been among the most prevalent combat-related injuries, accounting for 14% of all surgical procedures at Role 2/3 (R2/R3) facilities according to the DoD Trauma Registry. To further delineate the role of the deployed orthopedic surgeon on the modern battlefield, a retrospective review was performed highlighting both quantitative and qualitative analysis factors associated with orthopedic surgical care during the war in the Middle East.

METHODS

A retrospective review was conducted of orthopedic surgeons in the Middle East from 2001 to 2021. A comprehensive literature search was conducted using the PubMed and Embase databases using a two-reviewer strategy. Articles were compiled and reviewed using Covidence. Inclusion criteria included journal articles focusing on orthopedic injuries sustained during the Global War on Terror (GWoT) in an adult U.S. Military population. In the event of a conflict, a third author would determine the relevance of the article. For the remaining articles, a full-text review was conducted to extract relevant predetermined quantitative data, and the Delphi consensus method was then utilized to highlight relevant qualitative themes.

RESULTS

The initial search yielded 1,226 potentially relevant articles. In all, 40 studies ultimately met the eligibility criteria. With the consultation of previously deployed orthopedic surgeons at the Walter Reed National Military Medical Center, a retrospective thematic analysis of the 40 studies revealed five themes encompassing the orthopedic surgeons experience throughout GWoT. These themes include unique mechanisms of orthopedic injury compared to previous war injuries due to novel weaponry, differences in interventions depending on R2 versus R3 locations, differences in injuries from those seen in civilian settings, the maintained emphasis on humanitarian aspect of an orthopedic surgeon's mission, and lastly relation of pre-deployment training to perceived deployed success of the orthopedic surgeons. From this extensive review, we found that explosive mechanisms of injury were greatly increased when compared to previous conflicts and were the etiology for the majority of orthopedic injuries sustained. With the increase of complex explosive injuries in the setting of improved body armor and overall survival, R2/3 facilities showed an increased demand for orthopedic intervention including debridement, amputations, and external fixation. Combat injuries sustained during the GWoT differ in the complications, management, and complexity when compared to civilian trauma. "Humanitarian" cases made up a significant number of operative cases for the deployed orthopedic surgeon. Lastly, heterogeneous training opportunities were available prior to deployment (fellowship, combat extremity surgical courses, and dedicated pre-deployment training), and the most commonly identified useful training was learning additional soft-tissue coverage techniques.

CONCLUSION

These major themes indicate an emphasis on pre-deployment training and the strategic positioning of orthopedic surgeons to reflect the changing landscape of musculoskeletal trauma care. Moving forward, these authors recommend analyzing the comfort and perceived capability of orthopedic surgeons in these unique military environments to best prepare for a changing operational format and the possibility of future peer-peer conflicts that will likely lead to a lack of medical evacuation and prolonged field care.

Effect of valproic acid upon skeletal muscle subjected to prolonged tourniquet application

Background

Valproic acid (VPA), a histone deacetylase inhibitor, has shown improved outcomes when used as a pharmaceutical intervention in animal studies of hemorrhage, septic shock, and combined injuries. This study was designed to investigate the ability of VPA to mitigate ischemia-reperfusion injury produced by prolonged tourniquet application to an extremity.

Methods

The ischemia-reperfusion model in anesthetized rats was established using hemorrhage and a 3-hour tourniquet application. VPA was administered intravenously prior to tourniquet wear and removal. Ischemia-reperfusion injury was evaluated by investigating pathway signaling, immune modulation of cytokine release, remote organ injury, and skeletal muscle function during convalescence.

Results

We found that VPA sustained Protein kinase B (Akt) phosphorylation and Insulin-like growth factor signaling and modulated the systemic release of interleukin (IL)-1β, tumor necrosis factor alpha, and IL-6 after 2 hours of limb reperfusion. Additionally, VPA attenuated a loss in glomerular filtration rate at 3 days after injury. Histological and functional evaluation of extremity skeletal muscle at 3, 7, and 21 days after injury, however, demonstrated no significant differences in myocytic degeneration, necrotic formation, and maximal isometric tetanic torque.

Conclusions

Our results demonstrate that VPA sustains early prosurvival cell signaling, reduces the inflammatory response, and improves renal function in a hemorrhage with prolonged ischemia and reperfusion model. However, these do not translate into meaningful preservation in limb function when applied as a pharmaceutical augmentation to tourniquet wear.

Level of evidence

IV.

The Concept of Scaffold-Guided Bone Regeneration for the Treatment of Long Bone Defects: Current Clinical Application and Future Perspective

The treatment of bone defects remains a challenging clinical problem with high reintervention rates, morbidity, and resulting significant healthcare costs. Surgical techniques are constantly evolving, but outcomes can be influenced by several parameters, including the patient's age, comorbidities, systemic disorders, the anatomical location of the defect, and the surgeon's preference and experience. The most used therapeutic modalities for the regeneration of long bone defects include distraction osteogenesis (bone transport), free vascularized fibular grafts, the Masquelet technique, allograft, and (arthroplasty with) mega-prostheses. Over the past 25 years, three-dimensional (3D) printing, a breakthrough layer-by-layer manufacturing technology that produces final parts directly from 3D model data, has taken off and transformed the treatment of bone defects by enabling personalized therapies with highly porous 3D-printed implants tailored to the patient. Therefore, to reduce the morbidities and complications associated with current treatment regimens, efforts have been made in translational research toward 3D-printed scaffolds to facilitate bone regeneration. Three-dimensional printed scaffolds should not only provide osteoconductive surfaces for cell attachment and subsequent bone formation but also provide physical support and containment of bone graft material during the regeneration process, enhancing bone ingrowth, while simultaneously, orthopaedic implants supply mechanical strength with rigid, stable external and/or internal fixation. In this perspective review, we focus on elaborating on the history of bone defect treatment methods and assessing current treatment approaches as well as recent developments, including existing evidence on the advantages and disadvantages of 3D-printed scaffolds for bone defect regeneration. Furthermore, it is evident that the regulatory framework and organization and financing of evidence-based clinical trials remains very complex, and new challenges for non-biodegradable and biodegradable 3D-printed scaffolds for bone regeneration are emerging that have not yet been sufficiently addressed, such as guideline development for specific surgical indications, clinically feasible design concepts for needed multicentre international preclinical and clinical trials, the current medico-legal status, and reimbursement. These challenges underscore the need for intensive exchange and open and honest debate among leaders in the field. This goal can be addressed in a well-planned and focused stakeholder workshop on the topic of patient-specific 3D-printed scaffolds for long bone defect regeneration, as proposed in this perspective review.

Exploring skeletal muscle tolerance and whole-body metabolic effects of FDA-approved drugs in a volumetric muscle loss model

Volumetric muscle loss (VML) is associated with persistent functional impairment due to a lack of de novo muscle regeneration. As mechanisms driving the lack of regeneration continue to be established, adjunctive pharmaceuticals to address the pathophysiology of the remaining muscle may offer partial remediation. Studies were designed to evaluate the tolerance and efficacy of two FDA-approved pharmaceutical modalities to address the pathophysiology of the remaining muscle tissue after VML injury: (1) nintedanib (an anti-fibrotic) and (2) combined formoterol and leucine (myogenic promoters). Tolerance was first established by testing low- and high-dosage effects on uninjured skeletal muscle mass and myofiber cross-sectional area in adult male C57BL/6J mice. Next, tolerated doses of the two pharmaceutical modalities were tested in VML-injured adult male C57BL/6J mice after an 8-week treatment period for their ability to modulate muscle strength and whole-body metabolism. The most salient findings indicate that formoterol plus leucine mitigated the loss in muscle mass, myofiber number, whole-body lipid oxidation, and muscle strength, and resulted in a higher whole-body metabolic rate (p ≤ 0.016); nintedanib did not exacerbate or correct aspects of the muscle pathophysiology after VML. This supports ongoing optimization efforts, including scale-up evaluations of formoterol treatment in large animal models of VML.

Lower Extremity Response to Blast Loading: A Computational Study

This study has investigated the response of the Total Human Model for Safety (THUMS) lower extremity finite element model under blast loading. Response of the model was estimated in simulated underbody blast (UBB) loading using floorplate impact velocities of increasing severity. Correlation and analysis (CORA) ratings suggested a good match between numerical response and available experimental data. The model response was then investigated in an antipersonnel landmine explosion. The model was found stable in the nearfield blast and sensitive to the threat definition. The lower extremity injury was predicted when detonation occurred below the heel. The model predicted major injuries localized to the hindfoot and midfoot with minimal damage to the forefoot, consistent with the findings in the literature. The damage to the individual bones of the foot was measured in terms of percentage change in mass and element eroded.

Exoskeletal solutions to enable mobility with a lower leg fracture in austere environments

The treatment and evacuation of people with lower limb fractures in austere environments presents unique challenges that assistive exoskeletal devices could address. In these dangerous situations, independent mobility for the injured can preserve their vital capabilities so that they can safely evacuate and minimize the need for additional personnel to help. This expert view article discusses how different exoskeleton archetypes could provide independent mobility while satisfying the requisite needs for portability, maintainability, durability, and adaptability to be available and useful within austere environments. The authors also discuss areas of development that would enable exoskeletons to operate more effectively in these scenarios as well as preserve the health of the injured limb so that definitive treatment after evacuation will produce better outcomes.

Isolated limb fractures - the underestimated injury in the Israeli Defence Forces (IDF)

INTRODUCTION

Musculoskeletal injuries dominate warfare-related trauma and differ from civilian settings in higher hospitalization costs, morbidity, and mortality. Partly due to introduction of personal protective equipment in the Israel Defence Force (IDF) to minimize head and torso injuries while the extremities remained unprotected. This study describes military extremity injury patterns, prehospital treatment and injury sequela regarding return-to-duty and disability compensation.

METHODS

This retrospective study examined cases of battle and non-battle trauma casualties treated by the IDF Medical Corps from 2013 to 2020. Data from the IDF Trauma Registry (IDF-TR) was merged with The Israeli National Trauma Registry (INTR). Cases with high morbidity discharged from military service were compared with lower morbidity patients who returned to active duty service.

RESULTS

Out of 1360 injured soldiers, 280 (20.6%) were found to have isolated limb fractures (ILFs). High morbidity casualties had more open fractures (63% vs. 42%) and higher involvement of lower extremities (79% vs. 58%) (p < 0.001), higher rates of tourniquets use (28% compared to 9%, p < 0.001), external fixation (34% vs. 19%, p < 0.001) and amputations (9% vs. 1%, p = 0.003), required more rehabilitation (34% vs. 7%, p < 0.001), and had 46% medical disabilities compared to 24% with low morbidity (p < 0.001).

CONCLUSIONS

ILFs are associated with significant morbidity and disability. High morbidity is associated with high energy, scar-producing, lower-extremity open fractured limbs treated by tourniquets. Future studies should evaluate whether junctional or extremity protective gear is combat feasible and whether introducing Clinical Practice Guidelines to manage suspected limb fractures can decrease morbidity rates and improve return to duty.

Effects of extremity trauma on physiological responses to hemorrhage in conscious rats

Although physiological responses to hemorrhage are well-studied, hemorrhage is often accompanied by trauma, and it remains unclear how injury affects these responses. This study examined effects of extremity trauma on cardiorespiratory responses and survival to moderate (37%; H-37) or severe (50%; H-50) hemorrhage in rats. Transmitter and carotid catheter implantation and extremity trauma (fibular fracture and muscle injury) were conducted 2 wk, 24 h, and 90 min, respectively, before conscious hemorrhage. Mean arterial pressure (MAP) and heart rate (HR; via telemetry), and respiration rate (RR), minute volume (MV), and tidal volume (TV; via plethysmography) were measured throughout the 25 min hemorrhage and remainder of the 4 h observation period. There were four groups: 1) H-37, no trauma (NT; n = 17); 2) H-37, extremity trauma (T, n = 18); 3) H-50, NT (n = 20); and 4) H-50, T (n = 20). For H-37, during and after hemorrhage, T increased HR (P ≤ 0.031) and MV (P ≤ 0.048) compared with NT rats. During H-50, T increased HR (0.041) and MV (P = 0.043). After hemorrhage, T increased MV (P = 0.008) but decreased HR (P = 0.007) and MAP (P = 0.039). All cardiorespiratory differences between T and NT groups were intermittent. Importantly, both survival time (159.8 ± 78.2 min vs. 211.9 ± 60.3 min; P = 0.022; mean ± SD) and percent survival (45% vs. 80%; P = 0.048) were less in T versus NT rats after H-50. Trauma interacts with physiological systems in a complex manner and no single cardiorespiratory measure was sufficiently altered to indicate that it alone could account for increased mortality after H-50.NEW & NOTEWORTHY In both civilian and military settings, severe hemorrhage rarely occurs in the absence of tissue trauma, yet many animal models for the study of hemorrhage do not include significant tissue trauma. This study using conscious unrestrained rats clearly demonstrates that extremity trauma worsens the probability of survival after a severe hemorrhage. Although no single cardiorespiratory factor accounted for the increased mortality, multiple modest time-related cardiorespiratory responses to the trauma were observed suggesting that their combined dysfunction may have contributed to the reduced survival.

3D Bioprinted Patient-Specific Extracellular Matrix Scaffolds for Soft Tissue Defects

Soft tissue injuries such as volumetric muscle loss (VML) are often too large to heal normally on their own, resulting in scar formation and functional deficits. Decellularized extracellular matrix (dECM) scaffolds placed into these wounds have shown the ability to modulate the immune response and drive constructive healing. This provides a potential solution for functional tissue regeneration, however, these acellular dECM scaffolds are challenging to fabricate into complex geometries. 3D bioprinting is uniquely positioned to address this, being able to create patient-specific scaffolds based on clinical 3D imaging data. Here, a process to use freeform reversible embedding of suspended hydrogels (FRESH) 3D bioprinting and computed tomography (CT) imaging to build large volume, patient-specific dECM patches (≈12 × 8 × 2 cm) for implantation into canine VML wound models is developed. Quantitative analysis shows that these dECM patches are dimensionally accurate and conformally adapt to the surface of complex wounds. Finally, this approach is extended to a human VML injury to demonstrate the fabrication of clinically relevant dECM scaffolds with precise control over fiber alignment and micro-architecture. Together these advancements represent a step towards an improved, clinically translatable, patient-specific treatment for soft tissue defects from trauma, tumor resection, and other surgical procedures.

Field tourniquets in an austere military environment: A prospective case series

OBJECTIVE

Field tourniquets are often used for battlefield extremity injuries. Their effectiveness has been documented by a large combat theater trauma center. However, their use and effectiveness by an austere forward surgical team has not been reported. Aims of this study were to determine: Whether field tourniquets: (1) Were placed for appropriate indications; (2) significantly reduced hemorrhage as measured by transfusion requirements; (3) influenced vital signs and injury severity scores; and (4) did they cause limb amputation, changed amputation level, or other complications.

METHODS

Twenty-five patients with 30 involved extremities presenting to a forward surgical team in Iraq met the inclusion criteria. We prospectively collected data regarding the presence, indications for, and effectiveness of field tourniquets based on the need for blood transfusion. We recorded any complications associated with their use.

RESULTS

Tourniquets significantly reduced hemorrhage from penetrating injuries as measured by transfusion requirements. Those having major vascular injuries with effective tourniquets, a total of 12 units of blood were transfused (1.7 units/vascular injury; 2 units/patient). However, 19 units were transfused in patients (3.3 units/vascular injury; 3.8 units/patient) who had an ineffective or no tourniquet (p = 0.0006). Transfusion requirements were related the presence of an effective tourniquet regardless of concomitant injuries. The group with effective tourniquets and compressed hemorrhage presented with higher mean systolic (p = 0.003) and diastolic (p = 0.023) blood pressures than the group with no tourniquets or ineffective ones. Complications included one peroneal nerve palsy and no amputations resulted from tourniquet application.

CONCLUSION

Field tourniquets applied for penetrating injuries with severe bleeding can significantly reduce transfusion requirements and help maintain adequate blood pressure. Tourniquets were not the proximate cause of amputation and did not determine the choice of immediate amputation level.

Metagenomic features of bioburden serve as outcome indicators in combat extremity wounds

Battlefield injury management requires specialized care, and wound infection is a frequent complication. Challenges related to characterizing relevant pathogens further complicates treatment. Applying metagenomics to wounds offers a comprehensive path toward assessing microbial genomic fingerprints and could indicate prognostic variables for future decision support tools. Wound specimens from combat-injured U.S. service members, obtained during surgical debridements before delayed wound closure, were subjected to whole metagenome analysis and targeted enrichment of antimicrobial resistance genes. Results did not indicate a singular, common microbial metagenomic profile for wound failure, instead reflecting a complex microenvironment with varying bioburden diversity across outcomes. Genus-level Pseudomonas detection was associated with wound failure at all surgeries. A logistic regression model was fit to the presence and absence of antimicrobial resistance classes to assess associations with nosocomial pathogens. A. baumannii detection was associated with detection of genomic signatures for resistance to trimethoprim, aminoglycosides, bacitracin, and polymyxin. Machine learning classifiers were applied to identify wound and microbial variables associated with outcome. Feature importance rankings averaged across models indicated the variables with the largest effects on predicting wound outcome, including an increase in P. putida sequence reads. These results describe the microbial genomic determinants in combat wound bioburden and demonstrate metagenomic investigation as a comprehensive tool for providing information toward aiding treatment of combat-related injuries.

Human muscle in gene edited pigs for treatment of volumetric muscle loss

Focusing on complex extremity trauma and volumetric muscle loss (VML) injuries, this review highlights: 1) the current pathophysiologic limitations of the injury sequela; 2) the gene editing strategy of the pig as a model that provides a novel treatment approach; 3) the notion that human skeletal muscle derived from gene edited, humanized pigs provides a groundbreaking treatment option; and 4) the impact of this technologic platform and how it will advance to far more multifaceted applications. This review seeks to shed insights on a novel treatment option using gene edited pigs as a platform which is necessary to overcome the clinical challenges and limitations in the field.

Musculoskeletal Conditions and Secondary Cardiovascular Morbidity Increase Veterans’ Rehabilitation and Orthopaedic Service Utilization

Background

Musculoskeletal conditions often affect patients’ mobility and ability to participate in health behaviors such as exercise, potentially affecting their systemic health. The purpose of this research is to determine how frequently cardiac-related comorbidities present in a veteran population with musculoskeletal service-connected disability and how this affects musculoskeletal health care utilization. 

Methodology

A retrospective cohort of Iraq and Afghanistan Veterans who received a Veterans Affairs (VA) disability determination for service-connected musculoskeletal disability were categorized according to the diagnosis of cardiac comorbidity including diabetes mellitus, hyperlipidemia, hypertension, and obesity, and atherosclerosis disease documented by ICD-9 codes in the VA administrative data. Among veterans with musculoskeletal service-connected disability, logistic regression was modeled to determine if musculoskeletal clinic utilization was associated with also having a cardiac comorbid condition. 

Results

Veterans with musculoskeletal disability had a comorbid cardiac disorder 43% of the time. Post-traumatic arthritis was the only musculoskeletal condition positively associated with comorbid cardiac conditions. Veterans with comorbid cardiac diagnoses had 26-37% higher odds of receiving care by physical and occupational therapy, physical medicine, and orthopaedic surgery clinics compared to veterans without comorbid cardiac disease.

Conclusions

Veterans in this cohort with musculoskeletal service-connected disability, plus cardiac conditions had greater clinic use for musculoskeletal and rehabilitation services compared to those without cardiac conditions. These results have implications for the rehabilitation and other health service needs of a new generation of veterans.

Preclinical evaluation of a commercially available biofilm disrupting wound lavage for musculoskeletal trauma

BACKGROUND

Treatment of open fractures remains a significant challenge in trauma care as these fractures are accompanied by extensive soft tissue damage, exposing the wound site to contaminants and increasing infection risk. Formation of biofilm, a capsule-like environment that acts as a barrier to treatment, is a primary mode by which infecting pathogens persist at the wound site. Therefore, a pressing need exists to identify irrigation methods that can disrupt biofilm and expose pathogens to treatment. This study aims to evaluate the antibiofilm wound lavage, Bactisure™, in comparison with saline for care of severe musculoskeletal wounds and elucidate potential effects on antibiotic treatment success.

METHODS

UAMS-1 Staphylococcus aureus biofilms were formed in vitro and treated with Bactisure™ wound lavage or sterile normal saline, alone, or in combination with sub-biofilm inhibitory levels of vancomycin. Characterization methods included quantification of biofilm biomass, quantification of viable biofilm bacteria, and biofilm matrix imaging. For in vivo assessment, a delayed treatment model of contaminated open fracture was used wherein a critical-sized defect was created in a rat femur and wound site inoculated with UAMS-1. Following a 6 h delay, wounds were debrided, irrigated with lavage of interest, and antibiotic treatments administered. Bacterial enumeration was performed on bone and hardware samples after two weeks.

RESULTS

An immediate reduction in biofilm biomass was observed in vitro following antibiofilm lavage treatment, with a subsequent 2- to 3- log reduction in viable bacteria achieved after 24 h. Furthermore, biofilms treated with antibiofilm lavage in combination with vancomycin exhibited a minor, but statistically significant, decrease in viable bacteria compared to irrigation alone. In vivo, a minor, not statistically significant, decrease in median bioburden was observed for the antibiofilm lavage compared to saline when used in combination with antibiotics. However, the percentage of bone and hardware samples with detectable bacteria was reduced from 50 to 38%.

CONCLUSIONS

These results suggest that the antibiofilm wound lavage, Bactisure™, may hold promise in mitigating infection in contaminated musculoskeletal wounds and warrants further investigation. Here, we proposed multiple mechanisms in vitro by which this antibiofilm lavage may help mitigate infection, and demonstrate this treatment slightly outperforms saline in controlling bioburden in vivo.

Management of conflict injuries to the upper limb. Part 1: assessment and early surgical care

Upper limb injuries are common in conflict zones. The functions of the upper limb are impossible to replicate with prosthetic replacement and wherever possible attempts should be made to preserve the limb with further secondary reconstruction aimed at restoration of function. Casualty assessment, haemorrhage control and resuscitation are simultaneously undertaken at the receiving medical facility. Primary surgical management involves decontamination and debridement, skeletal stabilization, restoration of vascularity, compartment fasciotomy where indicated and wound temporization with dressings. Operative findings and interventions should be documented and if evacuation of the casualty is possible, copies should be provided in the medical records to facilitate communication in the chain of care. Secondary procedures are required for further assessment and debridement prior to planning reconstruction and definitive fracture stabilization, nerve repair, wound cover or closure.

Health-Care Utilization and Expenditures Associated with Long-Term Treatment After Combat and Non-Combat-Related Orthopaedic Trauma

BACKGROUND

The long-term consequences of musculoskeletal trauma can be profound and can extend beyond the post-injury period. The surveillance of long-term expenditures among individuals who sustain orthopaedic trauma has been limited in prior work. We sought to compare the health-care requirements of active-duty individuals who sustained orthopaedic injuries in combat and non-combat (United States) environments using TRICARE claims data.

METHODS

We identified service members who sustained combat or non-combat musculoskeletal injuries between 2007 and 2011. Combat-injured personnel were matched to those in the non-combat-injured cohort on a 1:1 basis using biologic sex, year of the injury, Injury Severity Score (ISS), and age at the index hospitalization. Health-care utilization was surveyed through 2018. The total health-care expenditures over the post-injury period were the primary outcome. These were assessed as a total overall cost and then as costs adjusted per year of follow-up. We used negative binomial regression to identify the independent association between risk factors and health-care expenditures.

RESULTS

We identified 2,119 individuals who sustained combat-related orthopaedic trauma and 2,119 individuals who sustained non-combat injuries. The most common mechanism of injury within the combat-injured cohort was blast-related trauma (59%), and 418 individuals (20%) sustained an amputation. The total costs were $156,886 for the combat-injured group compared with $55,873 for the non-combat-injured group (p < 0.001). Combat-related orthopaedic injuries were associated with a 43% increase in health-care expenditures (incidence rate ratio, 1.43 [95% confidence interval, 1.19 to 1.73]). Severe ISS at presentation, ≥2 comorbidities, and amputations were also significantly associated with health-care utilization, as was junior enlisted rank, our proxy for socioeconomic status.

CONCLUSIONS

Health-care requirements and associated costs are substantial among service members sustaining combat and non-combat orthopaedic trauma. Given the sociodemographic characteristics of our cohort, we believe that these results are translatable to civilians who sustain similar types of musculoskeletal trauma.

Traumatic Wounds of the Foot and Ankle: The Landstuhl Regional Medical Center Experience and Historical Perspectives

As this is more of a reference article, I chose not to have an abstract similar to the paper I wrote in 2016 regarding flat feet in the military.

IDCRP Combat-Related Extremity Wound Infection Research

INTRODUCTION

Extremity trauma is the most common battlefield injury, resulting in a high frequency of combat-related extremity wound infections (CEWIs). As these infections are associated with substantial morbidity and may impact wounded warriors long after initial hospitalization, CEWIs have been a focus of the Infectious Disease Clinical Research Program (IDCRP). Herein, we review findings of CEWI research conducted through the IDCRP and discuss future and ongoing analyses.

METHODS

Military personnel with deployment-related trauma sustained between 2009 and 2014 were examined in retrospective analyses through the observational Trauma Infectious Disease Outcomes Study (TIDOS). Characteristics of wounded warriors with ≥1 open extremity wound were assessed, focusing on injury patterns and infection risk factors. Through a separate trauma-associated osteomyelitis study, military personnel with combat-related open fractures of the long bones (tibia, femur, and upper extremity) sustained between 2003 and 2009 were examined to identify osteomyelitis risk factors.

RESULTS

Among 1,271 wounded warriors with ≥1 open extremity wound, 16% were diagnosed with a CEWI. When assessed by their most severe extremity injury (i.e., amputation, open fracture, or open soft-tissue wound), patients with amputations had the highest proportion of infections (47% of 212 patients with traumatic amputations). Factors related to injury pattern, mechanism, and severity were independent predictors of CEWIs during initial hospitalization. Having a non-extremity infection at least 4 days before CEWI diagnosis was associated with reduced likelihood of CEWI development. After hospital discharge, 28% of patients with extremity trauma had a new or recurrent CEWI during follow-up. Risk factors for the development of CEWIs during follow-up included injury pattern, having either a CEWI or other infection during initial hospitalization, and receipt of antipseudomonal penicillin for ≥7 days. A reduced likelihood for CEWIs during follow-up was associated with a hospitalization duration of 15-30 days. Under the retrospective osteomyelitis risk factor analysis, patients developing osteomyelitis had higher open fracture severity based on Gustilo-Anderson (GA) and the Orthopaedic Trauma Association classification schemes and more frequent traumatic amputations compared to open fracture patients without osteomyelitis. Recurrence of osteomyelitis was also common (28% of patients with open tibia fractures had a recurrent episode). Although osteomyelitis risk factors differed between the tibia, femur, and upper extremity groups, sustaining an amputation, use of antibiotic beads, and being injured in the earlier years of the study (before significant practice pattern changes) were consistent predictors. Other risk factors included GA fracture severity ≥IIIb, blast injuries, foreign body at fracture site (with/without orthopedic implant), moderate/severe muscle damage and/or necrosis, and moderate/severe skin/soft-tissue damage. For upper extremity open fractures, initial stabilization following evacuation from the combat zone was associated with a reduced likelihood of osteomyelitis.

CONCLUSIONS

Forthcoming studies will examine the effectiveness of common antibiotic regimens for managing extremity deep soft-tissue infections to improve clinical outcomes of combat casualties and support development of clinical practice guidelines for CEWI treatment. The long-term impact of extremity trauma and resultant infections will be further investigated through both Department of Defense and Veterans Affairs follow-up, as well as examination of the impact on comorbidities and mental health/social factors.

Clinical translation of a patient-specific scaffold-guided bone regeneration concept in four cases with large long bone defects

Background

Bone defects after trauma, infection, or tumour resection present a challenge for patients and clinicians. To date, autologous bone graft (ABG) is the gold standard for bone regeneration. To address the limitations of ABG such as limited harvest volume as well as overly fast remodelling and resorption, a new treatment strategy of scaffold-guided bone regeneration (SGBR) was developed. In a well-characterized sheep model of large to extra-large tibial segmental defects, three-dimensional (3D) printed composite scaffolds have shown clinically relevant biocompatibility and osteoconductive capacity in SGBR strategies. Here, we report four challenging clinical cases with large complex posttraumatic long bone defects using patient-specific SGBR as a successful treatment.

Methods

After giving informed consent computed tomography (CT) images were used to design patient-specific biodegradable medical-grade polycaprolactone-tricalcium phosphate (mPCL-TCP, 80:20 ​wt%) scaffolds. The CT scans were segmented using Materialise Mimics to produce a defect model and the scaffold parts were designed with Autodesk Meshmixer. Scaffold prototypes were 3D-printed to validate robust clinical handling and bone defect fit. The final scaffold design was additively manufactured under Food and Drug Administration (FDA) guidelines for patient-specific and custom-made implants by Osteopore International Pte Ltd.

Results

Four patients (age: 23–42 years) with posttraumatic lower extremity large long bone defects (case 1: 4 ​cm distal femur, case 2: 10 ​cm tibia shaft, case 3: complex malunion femur, case 4: irregularly shaped defect distal tibia) are presented. After giving informed consent, the patients were treated surgically by implanting a custom-made mPCL-TCP scaffold loaded with ABG (case 2: additional application of recombinant human bone morphogenetic protein-2) harvested with the Reamer-Irrigator-Aspirator system (RIA, Synthes®). In all cases, the scaffolds matched the actual anatomical defect well and no perioperative adverse events were observed. Cases 1, 3 and 4 showed evidence of bony ingrowth into the large honeycomb pores (pores >2 ​mm) and fully interconnected scaffold architecture with indicative osseous bridges at the bony ends on the last radiographic follow-up (8–9 months after implantation). Comprehensive bone regeneration and full weight bearing were achieved in case 2 ​at follow-up 23 months after implantation.

Conclusion

This study shows the bench to bedside translation of guided bone regeneration principles into scaffold-based bone tissue engineering. The scaffold design in SGBR should have a tissue-specific morphological signature which stimulates and directs the stages from the initial host response towards the full regeneration. Thereby, the scaffolds provide a physical niche with morphology and biomaterial properties that allow cell migration, proliferation, and formation of vascularized tissue in the first one to two months, followed by functional bone formation and the capacity for physiological bone remodelling. Great design flexibility of composite scaffolds to support the one to three-year bone regeneration was observed in four patients with complex long bone defects.

The translational potential of this article

This study reports on the clinical efficacy of SGBR in the treatment of long bone defects. Moreover, it presents a comprehensive narrative of the rationale of this technology, highlighting its potential for bone regeneration treatment regimens in patients with any type of large and complex osseous defects.

Neutrophil and natural killer cell imbalances prevent muscle stem cell-mediated regeneration following murine volumetric muscle loss

Skeletal muscle is one of the largest tissues in the body and can regenerate when damaged through a population of resident muscle stem cells. A type of muscle trauma called volumetric muscle loss overwhelms the regenerative capacity of muscle stem cells and engenders fibrotic supplantation. A comparison of muscle injuries resulting in regeneration or fibrosis revealed that intercellular communication between neutrophils and natural killer cells impacts muscle stem cell-mediated repair. Perturbation of neutrophil–natural killer cell interactions resulted in a variation of healing outcomes and suggested that immunomodulatory interventions can be effective to prevent aberrant healing outcomes.

Volumetric muscle loss (VML) overwhelms the innate regenerative capacity of mammalian skeletal muscle (SkM), leading to numerous disabilities and reduced quality of life. Immune cells are critical responders to muscle injury and guide tissue resident stem cell– and progenitor-mediated myogenic repair. However, how immune cell infiltration and intercellular communication networks with muscle stem cells are altered following VML and drive pathological outcomes remains underexplored. Herein, we contrast the cellular and molecular mechanisms of VML injuries that result in the fibrotic degeneration or regeneration of SkM. Following degenerative VML injuries, we observed the heightened infiltration of natural killer (NK) cells as well as the persistence of neutrophils beyond 2 wk postinjury. Functional validation of NK cells revealed an antagonistic role in neutrophil accumulation in part via inducing apoptosis and CCR1-mediated chemotaxis. The persistent infiltration of neutrophils in degenerative VML injuries was found to contribute to impairments in muscle stem cell regenerative function, which was also attenuated by transforming growth factor beta 1 (TGFβ1). Blocking TGFβ signaling reduced neutrophil accumulation and fibrosis and improved muscle-specific force. Collectively, these results enhance our understanding of immune cell–stem cell cross talk that drives regenerative dysfunction and provide further insight into possible avenues for fibrotic therapy exploration.

Prosthesis satisfaction and quality of life in US service members with combat-related major lower-limb amputation

BACKGROUND

Military amputee patient care programs offer extensive services, including advanced prosthetic devices, to restore function and improve quality of life (QOL) among veterans and service members with combat-related limb loss, but research on satisfaction with these devices is limited.

OBJECTIVE

To assess prosthesis satisfaction and QOL in US service members and veterans with combat-related major lower-limb amputation.

STUDY DESIGN

Cross-sectional study.

METHODS

Eighty-six participants with combat-related major lower-limb amputation completed the Orthotics and Prosthetics Users' Survey (OPUS) Satisfaction with Device scale and Quality of Well-Being Scale, Self-Administered, for the Wounded Warrior Recovery Project.

RESULTS

Most participants (62%-88%) responded Agree or Strongly Agree to OPUS Satisfaction with Device items on the fit, weight, comfort, ease of donning, appearance, and durability of their prosthesis. By contrast, the majority of participants (55%-79%) responded Disagree or Strongly Disagree to items on clothes being free of wear and tear, skin free of abrasions and irritations, and the affordability of their prosthesis. In linear regression analysis, total OPUS Satisfaction with Device score was positively associated with Quality of Well-Being Scale, Self-Administered score (β = 0.0058; P = 0.004).

CONCLUSIONS

Findings indicate the majority of participants were satisfied with the overall functionality of their prosthesis, but dissatisfied with the effect of their prosthesis on clothing and skin, as well as expenses related to their prosthesis. Additionally, prosthesis satisfaction was positively associated with QOL.

AAOS/Major Extremity Trauma and Rehabilitation Consortium Clinical Practice Guideline Summary for Evaluation of Psychosocial Factors Influencing Recovery From Orthopaedic Trauma

The Clinical Practice Guideline for Evaluation of Psychosocial Factors Influencing Recovery from Adult Orthopaedic Trauma is based on a systematic review of current scientific and clinical research. The purpose of this clinical practice guideline is to improve outcomes after adult orthopaedic trauma by evaluating, and addressing, the psychosocial factors that affect recovery. This guideline contains one recommendation to address eight psychosocial factors after military and civilian adult orthopaedic trauma that may influence clinical, functional, and quality of life recovery. Furthermore, it addresses additional factors that may be associated with greater biopsychosocial symptom intensity, limitations, and/or diminished health-related quality of life. However, this guideline did not evaluate effective treatment strategies for the treatment or prevention of psychosocial factors. This guideline cannot be fully extrapolated to the treatment of children or adolescents. In addition, the work group highlighted the need for additional research because studies of general traumatic injuries do not always generalize to specific orthopaedic populations.

Laminin-111-Enriched Fibrin Hydrogels Enhance Functional Muscle Regeneration Following Trauma

Volumetric muscle loss (VML) is the surgical or traumatic loss of skeletal muscle, which can cause loss of limb function or permanent disability. VML injuries overwhelms the endogenous regenerative capacity of skeletal muscle and results in poor functional healing outcomes. Currently, there are no approved tissue engineering treatments for VML injuries. In this study, fibrin hydrogels enriched with laminin-111 (LM-111; 50-450 μg/mL) were used for the treatment of VML of the tibialis anterior in a rat model. Treatment with fibrin hydrogel containing 450 μg/mL of LM-111 (FBN450) improved muscle regeneration following VML injury. FBN450 hydrogel treatment increased the relative proportion of contractile to fibrotic tissue as indicated by the myosin: collagen ratio on day 28 post-VML injury. FBN450 hydrogels also enhanced myogenic protein expression and increased the quantity of small to medium size myofibers (500-2000 μm²) as well as innervated myofibers. Improved contractile tissue deposition due to FBN450 hydrogel treatment resulted in a significant improvement (∼60%) in torque production at day 28 postinjury. Taken together, these results suggest that the acellular FBN450 hydrogels provide a promising therapeutic strategy for VML that is worthy of further investigation.

Wartime upper-extremity injuries in the Sahelian strip: Experience from a French Forward Surgical Team deployed in Mali

This study aimed to analyze upper-extremity combat-related injuries (CRIs) and non-combat-related injuries (NCRIs) treated in the French Forward Surgical Team currently deployed in Gao, Mali. A retrospective study was conducted using the French Military Health Service OpEX surgical database from February 2013 to March 2020. All patients operated on for upper-extremity injury were included: 224 patients, with a mean age of 28.15 years, for 249 upper-extremity injuries. Seventy-six (33.9%) sustained CRIs and 148 (66.1%) NCRIs. Multiple upper-extremity injuries and associated injuries were significantly more common in the CRI group. The majority of NCRIs involved the hand. Debridement and wound care was the most common procedure in both groups. External fixation and fasciotomy were significantly more frequent in the CRI group, and internal fracture fixation in the NCRI group. The overall number of procedures was significantly higher in the CRI group. Due to the high frequency of upper-extremity injury in current theaters of operations, deployed orthopedic surgeons should be trained in basic hand surgery so as to optimally manage both CRIs and NCRIs.

Complications in the Treatment of Delayed Union and Underlying Chronic Osteomyelitis After Right Crural Fracture Treated With Anterolateral Thigh Flap and Double-Barrelled Vascularized Fibula Graft

Background: Segmental bone defects pose a major, unsolved clinical challenge and may be the result of high-energy trauma, infection, and tumour resection or revision surgery. Several options exist to reconstruct, including Ilizarov bone transport, Masquelet technique, cylindrical mesh technique, allografts, and vascularized bone autografts. We present a patient with a delayed union of the tibia with concomitant chronic osteomyelitis treated with anterolateral thigh (ALT) flap and double-barrelled vascularized fibula graft.

Case presentation:A 60-year-old male with a chronic pretibial wound with underlying osteomyelitis of the right leg presented himself at the emergency department and was admitted to the surgical ward. He had complex chronic osteomyelitis of a tibial non-union after an earlier right crural fracture (a previous work-related accident). He was treated with an ALT flap and double-barrelled vascularized fibula graft, which was complicated with an additional fracture and breakage of osteosynthesis material.

Conclusion: Segmental bone defects pose a major, unsolved clinical challenge in orthopaedic, trauma-surgical, and plastic surgical practice. Concomitant infections and fractures can be part of the postoperative course. Patients with complex segmental bone defects need to be treated by a multidisciplinary team including at least an (orthopaedic) trauma surgeon, a plastic surgeon, and an infectiologist.

Verification of High-Rate Vertical Loading Laboratory Skeletal Fractures by Comparison with Theater Injury Patterns

For the current study, an existing theater injury data set was compared to component and whole body experiments meant to replicate the theater high rate vertical loading environment. The theater injury data set was derived from real world events that were within the design range of the Warrior Injury Assessment Manikin. A qualitative and quantitative assessment of the whole body fracture patterns was developed to determine whether the laboratory loading was correctly representing the resulting injuries seen in theater Underbody Blast (UBB) events. Results indicated that most of the experimental test fracture patterns were similar to the theater injuries for Abbreviated Injury Scale body regions of interest (lower extremities, pelvis, and spine); however, some of the body regions had higher similarity scores compared to others. Whole body fracture distribution was less similar than the component tests because of differences in injury distributions. The lower extremity whole body similarity was lower than spine and pelvis similarity. This analysis was able to identify some experimental tests that might not represent theater loading. In conclusion, this analysis confirmed that some laboratory testing produced skeletal injury patterns that are seen in comparable theater UBB events.

Towards bioengineered skeletal muscle: recent developments in vitro and in vivo

Skeletal muscle is a functional tissue that accounts for approximately 40% of the human body mass. It has remarkable regenerative potential, however, trauma and volumetric muscle loss, progressive disease and aging can lead to significant muscle loss that the body cannot recover from. Clinical approaches to address this range from free-flap transfer for traumatic events involving volumetric muscle loss, to myoblast transplantation and gene therapy to replace muscle loss due to sarcopenia and hereditary neuromuscular disorders, however, these interventions are often inadequate. The adoption of engineering paradigms, in particular materials engineering and materials/tissue interfacing in biology and medicine, has given rise to the rapidly growing, multidisciplinary field of bioengineering. These methods have facilitated the development of new biomaterials that sustain cell growth and differentiation based on bionic biomimicry in naturally occurring and synthetic hydrogels and polymers, as well as additive fabrication methods to generate scaffolds that go some way to replicate the structural features of skeletal muscle. Recent advances in biofabrication techniques have resulted in significant improvements to some of these techniques and have also offered promising alternatives for the engineering of living muscle constructs ex vivo to address the loss of significant areas of muscle. This review highlights current research in this area and discusses the next steps required towards making muscle biofabrication a clinical reality.

Fidelity of a Traffic Safety Education Intervention for Combat Veterans

Equipoise, feasibility, and fidelity were studied for the control condition of an occupational therapy driving intervention in a randomized controlled trial. We ranked equipoise and feasibility of six traffic safety education methods and created an implementation fidelity competency checklist. Education method selection was informed using the proportion of concordant ranks analysis while literature and a peer review informed competency checklist development. A proctored-online course delivery had the highest rater agreement (equipoise = .96 [.87-1.00]; feasibility = .99 [.97-1.00]). Implementation fidelity was supported by a 19-component training and evaluation checklist. This study supports promoting the scientific rigor of the RCT via - equipoise, feasibility, and implementation fidelity.

Lower extremity reconstruction for limb salvage and functional restoration - The Combat experience

Evolution in extremity injury treatment often occurs during major conflicts, with lessons learned applied and translated among military and civilian settings. In recent periods of war, improvements in protective equipment, in-theater damage control resuscitation/surgery, delivery of antibiotics locally/systemically, and rapid evacuation to higher levels of medical care capabilities have greatly improved combat casualty survivability rates. Additionally, widespread application of lower extremity tourniquets also has prevented casualties from exsanguination, thus reducing hemorrhagic-related deaths. Secondary to these, a high number of combat casualties suffering lower extremity traumatic injuries have presented for functional limb reconstruction and restoration as well as residual limb care.

Promoting endogenous repair of skeletal muscle using regenerative biomaterials

Skeletal muscles normally have a remarkable ability to repair themselves; however, large muscle injuries and several myopathies diminish this ability leading to permanent loss of function. No clinical therapy yet exists that reliably restores muscle integrity and function following severe injury. Consequently, numerous tissue engineering techniques, both acellular and with cells, are being investigated to enhance muscle regeneration. Biomaterials are an essential part of these techniques as they can present physical and biochemical signals that augment the repair process. Successful tissue engineering strategies require regenerative biomaterials that either actively promote endogenous muscle repair or create an environment supportive of regeneration. This review will discuss several acellular biomaterial strategies for skeletal muscle regeneration with a focus on those under investigation in vivo. This includes materials that release bioactive molecules, biomimetic materials and immunomodulatory materials.

Nerve Reconstruction Using Processed Nerve Allograft in the U.S. Military

BACKGROUND

Processed nerve allograft (PNA) is an alternative to autograft for the reconstruction of peripheral nerves. We hypothesize that peripheral nerve repair with PNA in a military population will have a low rate of meaningful recovery (M ≥ 3) because of the frequency of blasting mechanisms and large zones of injury.

METHODS

A retrospective review of the military Registry of Avance Nerve Graft Evaluating Utilization and Outcomes for the Reconstruction of Peripheral Nerve Discontinuities database was conducted at the Walter Reed Peripheral Nerve Consortium. All adult active duty military patients who underwent any peripheral nerve repair with PNA for complete nerve injuries augmented with PNA visit were included. Motor strength and sensory function were reported as a consensus from the multidisciplinary Peripheral Nerve Consortium. Motor and sensory testing was conducted in accordance with the British Medical Research Council.

RESULTS

A total of 23 service members with 25 nerve injuries (3 sensory and 22 mixed motor/sensory) underwent reconstruction with PNA. The average age was 30 years and the majority were male (96%). The most common injury was to the sciatic nerve (28%) from a complex mechanism (gunshot, blast, compression, and avulsion). The average defect was 77 mm. Twenty-four percent of patients achieved a meaningful motor recovery. Longer follow-up was correlated with improved postoperative motor function (r = 0.49 and P = .03).

CONCLUSIONS

The military population had complex injuries with large nerve gaps. Despite the low rate of meaningful recovery (27.3%), large gaps in motor and mixed motor/sensory nerves are difficult to treat, and further research is needed to determine if autograft would achieve superior results.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic, Level III.

A Focus on Non-Amputation Combat Extremity Injury: 2001-2018

INTRODUCTION

Extremity injuries have comprised the majority of battlefield injuries in modern U.S. conflicts since World War II. Most reports have focused on serious injuries only and, to date, no reports have described the full extent of combat extremity injuries, from mild to severe, resulting from post-9/11 conflicts. This study aims to identify and characterize the full spectrum of non-amputation combat-related extremity injury and extend the findings of previous reports.

METHODS

The Expeditionary Medical Encounter Database was queried for all extremity injured service members (SMs) deployed in support of post-9/11 conflicts through July 2018. Only injuries incurred during combat operations were included in this report. Major amputations were excluded as well as SMs killed in action or who died of wounds. Extremity injuries were categorized by body region, nature of injury, and severity. Demographics and injury event characteristics are also presented.

RESULTS

A total of 17,629 SMs sustained 42,740 extremity injuries during 18,004 separate injury events. The highest number of SMs were injured in 2004 (n = 3,553), 2007 (n = 2,244), and 2011 (n = 2,023). Injured SMs were mostly young (78% under 30 years), male (97%), junior- to mid-level enlisted (89%), in the Army (69%) or Marine Corps (28%), active duty (84%), serving as infantry and gun crew (59%), and injured in support of Operation Iraqi Freedom (60%). Blast weaponry was responsible for 75% of extremity injuries. Injuries were similarly distributed between the lower (52%) and upper (48%) extremities. The most common sites of lower extremity injury were the lower leg/ankle complex (40%) and thigh (26%). The most common upper extremities sites were the shoulder and upper arms (37%), and the hand, wrist, and fingers (33%). Nearly half (48%) of all extremity injuries were open wounds (48%), followed by fractures (20%) and contusions/superficial injuries (16%). SMs sustained an average of 2.4 extremity injuries per event and 56% of injuries were considered mild, with a median Injury Severity Score (ISS) of 3.

CONCLUSION

This study is the first publication to capture, review, and characterize the full range, from mild to severe, of non-amputation combat-related extremity injuries resulting from post-9/11 conflicts. The high prevalence of extremity injury, particularly in such a young population, and associated short- and long-term health outcomes, will impact military health care systems for decades to come.

How Common Are Civilian Blast Injuries in the National Trauma Databank, and What Are the Most Common Mechanisms and Characteristics of Associated Injuries?

BACKGROUND

Recent military conflicts have produced substantial improvements in the care of service members who experience blast injuries. As conflicts draw down, it is important to preserve and improve skills gained in combat. It is unknown whether civilian blast injuries can serve as a surrogate for military blast trauma. To guide further research, it is crucial to understand the volume, severity, and distribution of civilian blast injury in the civilian population.

QUESTIONS/PURPOSES

(1) What proportion of US trauma admissions are a result of blast injury? (2) What are the common mechanisms, and what is the demographic breakdown of civilian patients presenting to trauma centers after blast injuries? (3) What is the severity, and what are the characteristics of injuries sustained by civilian patients after blast injuries?

METHODS

We queried the American College of Surgeons National Trauma Databank (NTDB), a national aggregation of trauma registry data which captures robust mechanism of injury and wounding pattern information, for any patient admitted for trauma and an initial mechanism of injury corresponding to a predefined list of ICD-9 and ICD-10 external cause of injury codes related to blast injuries and reported as a proportion of all trauma-related admissions. Mechanisms were categorized into similar groups, and data were collected regarding demographics as well as location and intentionality of blast (that is, unintentional, the result of assault, or self-inflicted). Patient injuries were characterized by ICD-9 or ICD-10 diagnosis codes and sorted according to the body area affected and severity of injury, measured via the Injury Severity Score (ISS). The ISS is a measure of trauma severity, with scores ranging from 1 to 75 points based on injury severity, which is calculated according to injury scores in six separate body domains (head or neck, face, chest, abdomen or pelvis, extremities, external). A score of 1 represents a minor trauma to one region, while a score of 75 indicates injuries deemed nonsurvivable in one or more domains. Data were limited to trauma admissions in 2016.

RESULTS

Patients injured by blast mechanisms represented 0.3% (2682 of 968,843) of patients in NTDB-participating trauma centers who were treated after a blast injury in the year 2016; 86% (2315 of 2682) of these patients were men, and the mean ± SD age was 38 ± 21 years. Blast injuries most commonly occurred after detonation of fireworks (29% [773 of 2682]) or explosion of gas or pressurized containers (27% [732 of 2682]). The most commonly injured area of the body was the upper extremity (33% [894 of 2682]), followed by the face (28% [747 of 2682]), lower extremity (11% [285 of 2682]), thorax (10% [280 of 2682]), and head (10% [259 of 2682]). Fifty-eight percent (1564 of 2682) of patients had at least one burn injury. A total of 2% (51 of 2682) of the injuries were fatal, with a mean ISS score of 6 ± 8; 23% (608 of 2682) of patients presented with injuries classified as severe (ISS > 8).

CONCLUSION

Civilian blast-associated injuries are not common, but they can be severe, and in many (though not all) respects they seem similar to those described in published case series of military blast victims. Key differences include age and gender (civilian injuries more commonly involve women and older patients than do those in military studies). The potential of civilian blast patient care as a surrogate for study and clinical experience for military surgeons in the interwar period-as recommended by the National Academies of Sciences, Engineering, and Medicine report-is supported by our preliminary results. Future interventions or training programs would likely need to rely on multisite or targeted partnerships to encounter appropriate numbers of patients with blast injuries.

LEVEL OF EVIDENCE

Level IV, prognostic study.

Biomechanical evaluation of a tool-less external fixator

INTRODUCTION

Current external fixator systems used by the US and UK military for stabilising extremity fractures require specialised tools to build a construct. The goal of obtaining and maintaining limb length and alignment is not achieved if these tools are misplaced. An alternative, tool-less system is currently available, namely the Dolphix Temporary Fixation System. The aim of this study was to compare the stiffness of the Dolphix system with the existing Hoffmann III system.

METHODS

Three Hoffmann III and three Dolphix constructs were assembled on a bone (tibia) surrogate. A 30 mm fracture gap was created to simulate a comminuted proximal tibia or distal femur fracture. The constructs were then tested in cyclic axial compression once daily for 3 consecutive days.

RESULTS

The length and alignment of the surrogate limb was restored following each testing cycle with both external fixation systems. The stiffness of the constructs was maintained throughout each sequential test, with the Dolphix exhibiting 54% the stiffness of the Hoffmann III construct.

CONCLUSION

Given the Dolphix's performance in mechanical testing and the unique advantage of having a tool-less manual locking clamp mechanism, this tool-less system should be considered for use in the mobile austere environment.

Comparison of Carbapenem-Resistant Microbial Pathogens in Combat and Non-combat Wounds of Military and Civilian Patients Seen at a Tertiary Military Hospital, Philippines (2013-2017)

INTRODUCTION

Bacterial wound infections are a danger to both military and civilian populations. The nature of injury and infection associated with combat related wounds are important in guiding antibiotic prophylaxis and empiric treatment guidelines.

MATERIALS AND METHODS

The isolates were screened for drug-resistance by the MicroScan Walkaway Plus System using either the Negative Breakpoint Combo Panel (NBCP) 30 or 34 or Positive Breakpoint Combo Panel (PBPC) 20 or 23. Isolates with a minimum inhibitory concentration (MIC) of ≥8 μg/mL to imipenem and/or meropenem were tested for both carbapenemase production using the CarbaNP test and real-time PCR to determine molecular resistance mechanisms. Plasmid conjugation analysis was performed to define potential for horizontal gene transfer.

RESULTS

We characterized 634 bacterial wound isolates collected from September 2013 to December 2017 from patients seen at a Philippine military tertiary hospital presenting with combat or non-combat injuries [354 (military) and 280 (civilians)]. Staphylococcus aureus was the most predominant bacterial species isolated from wounds in both populations (104/634, 16%). A variety of Gram-negative bacterial species comprised 442/634 (70%) of the isolates identified, with the most prevalent shown to be Pseudomonas aeruginosa, Enterobacter cloacae, Klebsiella pneumoniae, Escherichia coli, and Acinetobacter sp. Carbapenemase production was detected in 34/442 (8%) Gram-negative isolates. Testing for molecular resistance mechanisms showed 32/34 (17 military, 15 civilian) wound isolates were blaNDM positive and 2 were blaVIM positive, with the two blaVIM isolates found in the civilian population. Plasmid conjugation of 14 blaNDM and 2 blaVIM positive wound isolates representatives showed 2/16 (13%) produced E. coli J53 transconjugants (E. coli from a civilian; E. cloacae from a military).

CONCLUSION

We describe in this study the wound bacterial and antibiotic resistance profile in the military (combat vs non-combat associated) and civilian population. We observed that, with the exception of Acinetobacter sp., resistance of prevalent Gram-negative bacterial species to imipenem or meropenem were not significantly different between the military and civilian populations. We also presented data on the prevalent bacterial species isolated from both combat and non-combat wounds in a military tertiary care hospital setting as well as the carbapenemase-encoding gene primarily responsible for carbapenem resistance as well as evidence of horizontal transfer via mobile genetic elements. Clinicians may use this information to guide empiric antibiotic coverage for the predominant organisms if wound culture results are not readily available.A prospective, longitudinal evaluation of the wound bacterial profile documenting the changing bacterial flora using higher resolution molecular strategies can provide a more comprehensive understanding of the diversity, composition, and abundance of bacterial composition of the wound microbial community from the time of injury, during the course of evacuation from the field to higher level of care facilities, and up to wound resolution.

Lower Extremity Combat Sustained Peripheral Nerve Injury in US Military Personnel

Background:

Since the civil war, combat sustained peripheral nerve injuries (CSPNI) have been documented during wartime. Warfare has evolved and current combat involves a greater severity of blast injuries secondary to increased use of improvised explosive devices. The purpose of this study was to describe CSPNI and report outcomes after evaluation and treatment. We hypothesize that a shorter time to evaluation will improve outcomes.

Methods:

A database including all active duty service members who sustained a CSPNI and were treated by the PNC between 2004 and 2009 was used. Service member demographic information, injury mechanism, CSPNI description, and Medical Research Council (MRC) final motor and sensory outcomes were queried from this database.

Results:

One hundred and four military service members sustained 144 PNIs. The average age was 26.7 years, and nearly all were men (98.1%). There was no correlation between Sunderland classification and age, specific PNI, injury type, or time to evaluation. Higher Sunderland classifications were found to be correlated with worse final motor (r = 0.51, P < 0.001) and final sensory (r = 0.41, P < 0.001) scores. Final motor and sensory scores were not associated with specific nerve injury, mechanism of injury, initial EMG, or surgical procedure. Shorter time to initial assessment was associated with improved final motor and sensory scores, but was not found to be statistically significant.

Conclusions:

As the complexity of CSPNIs progress as combat weaponry evolves, a firm understanding of treatment factors is important. Our study demonstrates in recent conflict that military service members’ initial injury severity is a key factor in expected outcome.

Bomb blast: imaging findings, treatment and clinical course of extremity traumas

Background

To describe the severity and types of blast-related extremity injuries and the presence of accompanying vascular injuries (VI) and amputation, and to identify the associated factors affecting the treatment management and clinical course.

Methods

The study included 101 patients with extremity injuries caused by a bomb explosion. The radiographs and computed tomography angiographies of the patients were evaluated in terms of injury patterns, presence of penetrating fragments and fractures, and localization (upper or lower extremity) and type (open or closed) of injury. The Gustilo-Anderson classification was used for open fractures. According to their severity, open fractures classified as types 1 and 2 were included in Group 1 and those classified as type 3A, 3B and 3C in Group 2.

Results

As a result of blast exposure, 101 (57.7%) patients had extremity injuries, of which 76 (75.2%) presented with at least one fracture. Of the total of 103 fractures, nine (8.8%) were closed and 94 (91.2%) were open. Thirty-eight (40.4%) of the open fractures were located in the upper extremities, and 56 (59.6%) in the lower extremities and pelvis. Open fractures were most frequently localized in the femur (n = 20; 21.2%), followed by the tibia (n = 18; 19.1%). The majority of patients with open fractures were in Group 1 (71.4%). The duration of hospital stay was longer in Group 2 (12.1 ± 5.8 vs. 6.3 ± 6.7 days, p <  0.0001, respectively). Mortality among patients in Group 2 (45.0%) was significantly higher than in Group 1 (8.0%) (p <  0.0001). Similarly, the injury severity score (ISS) was higher in Group 2 (median 20 vs. 9, p <  0.0001). VI was present in 13 (12.9%) of all patients, and amputation in seven (7.9%).

Conclusion

The presence of severe open fractures, VI, and high ISS score can be considered as important factors that increase morbidity and mortality. In extremity traumas, through the secondary blast mechanism, contaminated-fragmented tissue injuries occur. Therefore, we believe that it will be beneficial to apply damage control surgery in places with low socioeconomic level and poor hygienic conditions.

Pain, Depression, and Posttraumatic Stress Disorder Following Major Extremity Trauma Among United States Military Serving in Iraq and Afghanistan: Results From the Military Extremity Trauma and Amputation/Limb Salvage Study

OBJECTIVES

Assess the burden and co-occurrence of pain, depression, and posttraumatic stress disorder (PTSD) among service members who sustained a major limb injury, and examine whether these conditions are associated with functional outcomes.

DESIGN

A retrospective cohort study.

SETTING

Four U.S. military treatment facilities: Walter Reed Army Medical Center, National Naval Medical Center, Brooke Army Medical Center, and Naval Medical Center San Diego.

PATIENTS/PARTICIPANTS

Four hundred twenty-nine United States service members who sustained a major limb injury while serving in Afghanistan or Iraq met eligibility criteria upon review of their medical records.

INTERVENTION

Not applicable.

MAIN OUTCOME MEASUREMENTS

Outcomes assessed were: function using the short musculoskeletal functional assessment; PTSD using the PTSD Checklist and diagnostic and statistical manual criteria; pain using the chronic pain grade scale.

RESULTS

Military extremity trauma and amputation/limb salvage patients without pain, depression, or PTSD, were, on average, about one minimally clinically important difference (MCID) from age- and gender-adjusted population norms. In contrast, patients with low levels of pain and no depression or PTSD were, on average, one to 2 MCIDs from population norms. Military extremity trauma and amputation/limb salvage patients with either greater levels of pain, and who experience PTSD, depression, or both, were 4 to 6 MCIDs from population norms. Regression analyses adjusting for injury type (upper or lower limb, salvage or amputation, and unilateral or bilateral), age, time to interview, military rank, presence of a major upper limb injury, social support, presence of mild traumatic brain injury/concussion, and combat experiences showed that higher levels of pain, depression, and PTSD were associated with lower one-year functional outcomes.

CONCLUSIONS

Major limb trauma sustained in the military results in significant long-term pain and PTSD. Overall, the results are consistent with the hypothesis that pain, depression, and PTSD are associated with disability in this population.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Prolonged field care for traumatic extremity injuries: defining a role for biologically focused technologies

Extremity injuries occur frequently during warfare. While traditionally treated in definitive clinics, the future battlefield is projected to be different in a variety of ways, and there will likely be a shift towards prolonged field care (PFC) for treating extremity traumas. PFC is defined as field medical care that is applied beyond “doctrinal planning time-lines” by a tactical medical practitioner in order to decrease patient mortality and morbidity. At present, there is an urgent need to develop biologically focused technologies for treating extremity injuries in the PFC setting. Herein, the case is made for why rapid advancements in PFC is critical to achieve optimal care for injured Service members in the future, and important design criteria for developing next-generation biologically focused technologies. Finally, a case example—i.e., Gustilo Type III fracture—is presented to illustrate how these biologically focused technologies could be utilized to treat an extremity injury within a PFC environment.