Combat and Noncombat Musculoskeletal Injuries in the US Military

Load increases IMU signal attenuation per step but reduces IMU signal attenuation per kilometre

BACKGROUND

Despite deleterious biomechanics associated with injury, particularly as it pertains to load carriage, there is limited research on the association between physical demands and variables captured with wearable sensors. While inertial measurement units (IMUs) can be used as surrogate measures of ground reaction force (GRF) variables, it is unclear if these data are sensitive to military-specific task demands.

RESEARCH QUESTION

Can wearable sensors characterise physical load and demands placed on individuals in different load, speed and grade conditions?

METHODS

Data were collected on 20 individuals who were self-reportedly free from current injury, recreationally active, and capable of donning 23 kg in the form of a weighted vest. Each participant walked and ran on flat, uphill (+6 %) and downhill (-6 %) without and with load (23 kg). Data were collected synchronously from optical motion capture (OMC) and IMUs placed on the distal limb and the pelvis. Data from an 8-second window was used to generate a participant-based mean of OMC and IMU variables of interest. Repeated Measures ANOVA was used to measure main and interaction effects of load, speed, and grade. Simple linear regression was used to elucidate a relationship between OMC measures and estimated metabolic cost (EMC) to IMU measures.

RESULTS

Load reduces foot and pelvic accelerations (p<0.001) but elevate signal attenuation per step (p=0.044). Conversely, attenuation per kilometre is lowered with the addition of load (p=0.017). Uphill had the lowest attenuation per step (p=0.003) and kilometre (p≤0.033) in walking, while downhill had the greatest attenuation per step (p≤0.002) and per kilometre (p≤0.004). Attenuation measures are inconsistently moderately related to limb negative work (R≤0.57). EMC is moderately positively related to unloaded running (R≥0.39), and moderately negatively related to walking with and without load (R≤-0.52).

SIGNIFICANCE

While load reduces peak accelerations at both the pelvis and foot. However, it may increase demand on the lower extremity to attenuate the signal between the two sensors with each step, while attenuation over time reduces with load.

Common Data Elements and Databases Essential for the Study of Musculoskeletal Injuries in Military Personnel

INTRODUCTION

Injuries are the leading cause of medical encounters with over 2 million medical encounters for musculoskeletal (MSK) conditions and over 700,000 acute injuries per year. Musculoskeletal injuries (MSKIs) are by far the leading health and readiness problem of the U.S. Military. The Proceedings of the International Collaborative Effort on Injury Statistics published a list of 12 data elements deemed necessary for injury prevention in the civilian population; however, there are no standardized list of common data elements (CDEs) across the DoD specifically designed to study MSKIs in the Military Health System (MHS). This study aims to address this gap in knowledge by defining CDEs across the DoD for MSKIs, establishing a CDE dictionary, and compiling other necessary information to quantify MSKI disease burden in the MHS.

MATERIALS AND METHODS

Between November 2022 and March 2023, we conducted an environmental scan of current MSKI data metrics across the DoD. We used snowball sampling with active engagement of groups housing datasets that contained MSKI data elements to determine CDEs as well as information on readiness databases across the DoD containing up-to-date personnel information on disease, hospitalizations, limited duty days (LDDs), and deployability status for all military personnel, as well as MSKI-specific measures from the MHS Dashboard which tracks key performance measures.

RESULTS

We identified 8 unique databases: 5 containing demographic and diagnostic information (Defense Medical Surveillance System, Medical Assessment and Readiness Systems, Military Health System Data Repository, Person-Data Environment, and Soldier Performance, Health, and Readiness Database); and 3 containing LDD information (Aeromedical Services Information Management System, eProfile, and Limited Duty Sailor Marines Readiness Tracker). Nine CDEs were identified: DoD number, sex, race, ethnicity, branch of service, rank, diagnosis, Common Procedural Terminology coding, and cause codes, as they may be captured in any database that is a derivative of the Military Health System Data Repository. Medical Assessment and Readiness Systems contained most variables of interest, excluding injury/place of region and time in service. The Limited Duty Sailor Marines Readiness Tracker contains a variable corresponding to "days on limited duty." The Aeromedical Services Information Management System uses the "release date" and "profile date" to calculate LDDs. The eProfile system determines LDDs by the difference between the "expiration date" and "approved date." In addition, we identified 2 measures on the MHS Dashboard. One measures the percentage of service members (SMs) who are on limited duty for longer than 90 days because of an MSKI and the other tracks the percentage of SMs that are not medically ready for deployment because of a deployment-limiting medical condition.

CONCLUSIONS

This article identifies core data elements needed to understand and prevent MSKIs and where these data elements can be found. These elements should inform researchers and result in evidence-informed policy decisions supporting SM health to optimize military force readiness.

Viability of Structured Gait Retraining for Improving Clinical Outcomes Following Running-related Injury in Active Duty Service Members

INTRODUCTION

All branches of the U.S. Military have a running component of their physical readiness testing battery. Running-related musculoskeletal injuries affect 20 to 40% of DoD Service Members each year. Running form has not historically been addressed with military running-related injuries. To assess the utility of a structured gait retaining protocol designed to treat the onset of running-related pain and/or injury by correcting identified biomechanical risk factors for injury and improve clinical outcomes.

STUDY DESIGN

Case series.

MATERIALS AND METHODS

A total of 160 Active Duty Service Members (ADSMs) with running-related lower-body musculoskeletal injuries were referred by a physical therapist for a multisession gait retraining program termed "Run with CLASS" (Cadence, Lean, Alignment, Soft-landing, Strike). Run with CLASS utilized various drills to emphasize impact progression, proximal strengthening, and proprioception and spatial awareness.

RESULTS

Results revealed that the implemented gait retraining protocol significantly improved running parameters following lower-body injury as evidenced by increased cadence, improved functional assessment scores, and a marked transition from predominantly heel strike to forefoot strike patterns during running.

CONCLUSIONS

A 3-week supervised gait retraining program focused on the gait retraining program termed "Run with CLASS" (Cadence, Lean, Alignment, Soft-landing, Strike) was successful in altering biomechanics of self-selected running gait by increasing cadence and transitioning ADSMs to a forefoot foot strike. Additionally, ADSMs reported significant improvements on the self-reported functional scores on the University of Wisconsin Running Injury and Recovery Index and Single Assessment Numerical Evaluation.

LEVEL OF EVIDENCE

4.

United States Army Reserve/National Guard soldiers' healthcare experiences, attitudes, and preferences: Differences based on deployment status

Some United States Army Reserve/National Guard (USAR/NG) soldiers have substantial health needs, which may be service-related, but not necessarily resulting from deployment. However, most USAR/NG members need to have been deployed to qualify for Veterans Administration (VA) benefits. Therefore, many USAR/NG soldiers seek care from civilian healthcare providers (HCPs). Using a subset (N = 430 current/former soldiers) of Operation: SAFETY study data, we used regression models to examine differences in healthcare experiences, attitudes, and preferences by deployment status (never-deployed vs. previously-deployed). Final models controlled for age, sex, rank (enlisted vs. officer), military status (current vs. former military), and RAND SF-36 General Health Score. Over 40% of soldiers agreed that civilian HCPs should ask patients about their military service, but never-deployed soldiers were less likely to report being asked about their service (p < 0.05) or how their service affects their health (p < 0.10). Never-deployed soldiers were also less likely to attribute their health concerns to military service (p < 0.001). Although never-deployed soldiers were more likely to prefer receiving physical (p < 0.05) and mental (p < 0.05) healthcare outside of the VA than previously-deployed soldiers, never-deployed soldiers had low confidence in their HCP's understanding of their needs (49% thought that their civilian HCP did not understand them; 71% did not think that their civilian HCP could address military-related health concerns; 76% thought that their civilian HCP did not understand military culture). Findings demonstrate that although civilian HCPs may be the preferred (and only) choice for never-deployed USAR/NG soldiers, they may need additional support to provide care to this population.

Neuromuscular Polytrauma Pain is Resolved by Macrophage COX-2 Nanoimmunomodulation

Soft tissue injuries often involve muscle and peripheral nerves and are qualitatively distinct from single-tissue injuries. Prior research suggests that damaged innervation compromises wound healing. To test this in a traumatic injury context, we developed a novel mouse model of nerve and lower limb polytrauma, which features greater pain hypersensitivity and more sustained macrophage infiltration than either injury in isolation. We also show that macrophages are crucial mediators of pain hypersensitivity in this model by delivering macrophage-targeted nanoemulsions laden with the cyclooxygenase-2 (COX-2) inhibitor celecoxib. This treatment was more effective in males than females, and more effective when delivered 3 days post-injury than 7 days post-injury. The COX-2 inhibiting nanoemulsion drove widespread anti-inflammatory changes in cytokine expression in polytrauma-affected peripheral nerves. Our data shed new light on the modulation of inflammation by injured nerve input and demonstrate macrophage-targeted nanoimmunomodulation can produce rapid and sustained pain relief following complex injuries.

The Effect of Cautionary Versus Resiliency Spine Education on Maximum Deadlift Performance and Back Beliefs: A Randomized Control Trial

ABSTRACT

Scott, KM, Kreisel, BR, Florkiewicz, EM, Crowell, MS, Morris, JB, McHenry, PA, and Benedict, TM. The effect of cautionary versus resiliency spine education on maximum deadlift performance and back beliefs: A randomized control trial. J Strength Cond Res 38(7): e341-e348, 2024-The purpose of this study was to determine the effect of cautionary information about the spine vs. a message of spine resiliency on maximum deadlift (MDL) performance and beliefs regarding the vulnerability of the spine. This cluster randomized control trial involved 903 military new cadets (n = 903) during their mandatory fitness test in cadet basic training (mean age 18.3 years, body mass index 23.8 kg·m-2, 22% female). Subjects were cluster randomized to 3 groups. The cautionary group received a message warning them to protect their backs while deadlifting, the resiliency group received a message encouraging confidence while deadlifting, and the control group received the standardized Army deadlift education only. The outcome measures were MDL weight lifted and perceived spine vulnerability. Significance was set at alpha ≤0.05. There were no between-group differences in weight lifted (p=0.40). Most subjects believed that the spine is vulnerable to injury. Three times as many subjects who received the resiliency education improved their beliefs about the vulnerability of their spines compared with those receiving the cautionary education (p<0.001). This study demonstrated the potential for brief resiliency education to positively influence beliefs about spine vulnerability, whereas cautionary education did not impair performance.

IMUs Can Estimate Hip and Knee Range of Motion during Walking Tasks but Are Not Sensitive to Changes in Load or Grade

The ability to estimate lower-extremity mechanics in real-world scenarios may untether biomechanics research from a laboratory environment. This is particularly important for military populations where outdoor ruck marches over variable terrain and the addition of external load are cited as leading causes of musculoskeletal injury As such, this study aimed to examine (1) the validity of a minimal IMU sensor system for quantifying lower-extremity kinematics during treadmill walking and running compared with optical motion capture (OMC) and (2) the sensitivity of this IMU system to kinematic changes induced by load, grade, or a combination of the two. The IMU system was able to estimate hip and knee range of motion (ROM) with moderate accuracy during walking but not running. However, SPM analyses revealed IMU and OMC kinematic waveforms were significantly different at most gait phases. The IMU system was capable of detecting kinematic differences in knee kinematic waveforms that occur with added load but was not sensitive to changes in grade that influence lower-extremity kinematics when measured with OMC. While IMUs may be able to identify hip and knee ROM during gait, they are not suitable for replicating lab-level kinematic waveforms.

Treatment of Tendon Injuries in the Servicemember Population across the Spectrum of Pathology: From Exosomes to Bioinductive Scaffolds

Tendon injuries in military servicemembers are one of the most commonly treated nonbattle musculoskeletal injuries (NBMSKIs). Commonly the result of demanding physical training, repetitive loading, and frequent exposures to austere conditions, tendon injuries represent a conspicuous threat to operational readiness. Tendon healing involves a complex sequence between stages of inflammation, proliferation, and remodeling cycles, but the regenerated tissue can be biomechanically inferior to the native tendon. Chemical and mechanical signaling pathways aid tendon healing by employing growth factors, cytokines, and inflammatory responses. Exosome-based therapy, particularly using adipose-derived stem cells (ASCs), offers a prominent cell-free treatment, promoting tendon repair and altering mRNA expression. However, each of these approaches is not without limitations. Future advances in tendon tissue engineering involving magnetic stimulation and gene therapy offer non-invasive, targeted approaches for improved tissue engineering. Ongoing research aims to translate these therapies into effective clinical solutions capable of maximizing operational readiness and warfighter lethality.

The association between safety climate and noncombat injury events among United States Air Force workers

INTRODUCTION

Work-related injuries are a common lagging safety indicator whereas safety climate assessments can help identify constructs serving as leading indicators. The National Institute for Occupational Safety and Health (NIOSH) partnered with the U.S. Department of the Air Force (DAF) Safety Center to examine the association between perceptions of safety climate survey constructs and the number of injury events within the DAF workforce.

METHODS

The DAF administers voluntary, anonymous, occupation-specific safety climate surveys to DAF workers using the internal Air Force Combined Mishap Reduction System (AFCMRS). Survey responses from 2014 to 2018 provided by DAF workers and injury events in maintenance, support, and operations occupations were shared with NIOSH. Exploratory Factor Analysis revealed five constructs: Leadership and Communication; Organizational Safety Priority; Error Management; Resource Adequacy; and Deployment/Official Travel Impact. Squadron-level analysis included bivariate correlations and estimated Rate Ratios (RRs).

RESULTS

1,547 squadrons administered the survey, averaging 144 workers and 15.8 reportable injuries per squadron. Higher (more favorable) squadron-level construct scores were consistently correlated with fewer reported injuries (p < 0.001). Controlling for the number of workers, RRs revealed significant reductions in injury rates with each one-unit increase in responses: Leadership and Communication RR = 0.40 (95%CI: 0.32-0.48); Organizational Safety Priority RR = 0.50 (95%CI: 0.40-0.64); Error Management RR = 0.37 (95%CI: 0.30-0.47); Deployment/Official Travel Impact RR = 0.36 (95%CI: 0.29-0.45). Resource Adequacy revealed a non-significant lower injury rate RR = 0.87 (95%CI: 0.73-1.04).

CONCLUSIONS

This unique study quantified safety climate and the association with injuries across a multi-year period. While safety climate measurements may be limited by frequent turnover and the self-reported, voluntary, anonymous nature of AFCMRS, the strength of this study is in the census of injuries.

PRACTICAL APPLICATIONS

Future research should include longitudinal analyses to examine the impact on injuries when squadron leaders are provided feedback on safety climate survey results.

Prescribed footwear and orthoses are not prophylactic in preventing lower extremity injuries in military tactical athletes: a systematic review with meta-analysis

INTRODUCTION

Military members are exposed to high cumulative physical loads that frequently lead to injury. Prescribed footwear and orthoses have been used to prevent injury. The purpose of this systematic review with meta-analysis was to assess if prescribed prophylactic footwear or foot orthoses reduced the risk of lower extremity injury in military tactical athletes.

METHODS

MEDLINE, Embase, Web of Science, Cumulative Index to Nursing and Allied Health Literature, SportDiscus, and Defense Technical Information Center databases were searched for randomised controlled trials published at any time that compared foot orthoses or prescribed footwear (to include shock-absorbing insoles and socks) with a placebo intervention or a no-treatment control. Methodological quality was assessed and the number of injuries, population at risk and duration of the study epoch were extracted and relative risk (RR) calculated. An omnibus meta-analysis was performed assessing all prescribed footwear and orthoses intervention studies, with subgroup analyses conducted on studies with similar interventions (ie, basketball athletic shoes, athletic shoes (prescribed by foot type), foot orthoses, shock-absorbing insoles, socks, tropical combat boots).

RESULTS

Of 1673 studies identified, 22 were included. Three of eight studies that employed orthoses demonstrated significantly reduced overuse injuries compared with no-treatment controls (RR range: 0.34-0.68); one study showed neoprene insoles significantly decreased overuse injuries (RR: 0.75). There were no other significant effects in the individual studies and no protective effects observed in the omnibus meta-analysis or in the component subanalyses.

CONCLUSIONS

Prescribed footwear and orthoses do not appear to have a prophylactic effect on lower quarter musculoskeletal injuries in military members and cannot be recommended at this time.

Identifying special operative trainees at-risk for musculoskeletal injury using full body kinematics

Introduction: Non-combat musculoskeletal injuries (MSKIs) during military training significantly impede the US military's functionality, with an annual cost exceeding $3.7 billion. This study aimed to investigate the effectiveness of a markerless motion capture system and full-body biomechanical movement pattern assessments to predict MSKI risk among military trainees. Methods: A total of 156 male United States Air Force (USAF) airmen were screened using a validated markerless biomechanics system. Trainees performed multiple functional movements, and the resultant data underwent Principal Component Analysis and Uniform Manifold And Projection to reduce the dimensionality of the time-dependent data. Two approaches, semi-supervised and supervised, were then used to identify at-risk trainees. Results: The semi-supervised analysis highlighted two major clusters with trainees in the high-risk cluster having a nearly five times greater risk of MSKI compared to those in the low-risk cluster. In the supervised approach, an AUC of 0.74 was produced when predicting MSKI in a leave-one-out analysis. Discussion: The application of markerless motion capture systems to measure an individual's kinematic profile shows potential in identifying MSKI risk. This approach offers a novel way to proactively address one of the largest non-combat burdens on the US military. Further refinement and wider-scale implementation of these techniques could bring about substantial reductions in MSKI occurrence and the associated economic costs.

Clinical Outcomes After ACL Reconstruction in Soccer (Football, Futbol) Players: A Systematic Review and Meta-Analysis

CONTEXT

The risk factors for anterior cruciate ligament (ACL) tear for athletes participating in pivoting sports includes young age and female sex. A previous meta-analysis has reported a reinjury rate of 15% after ACL reconstruction (ACLR) for athletes across all sports. To the best of the authors' knowledge, this is the first systematic review and meta-analysis of available literature reporting outcomes after ACLR in soccer players.

OBJECTIVE

To review and aggregate soccer-specific outcomes data after ACLR found in current literature to help guide a more tailored discussion regarding expectations and prognosis for soccer players seeking operative management of ACL injuries.

DATA SOURCES

A comprehensive search of publications was performed using PubMed, EMBASE, Cochrane Central Register of Controlled Trials, and SPORTDiscus databases.

STUDY SELECTION

Inclusion criteria consisted of original studies, level of evidence 1 to 4, studies reporting clinical and patient-reported outcomes (PROs) after primary ACLR in soccer players at all follow-up length.

STUDY DESIGN

The primary outcomes of interest were graft failure/reoperation rates, ACL injury in contralateral knee, return to soccer time, and PROs.

LEVEL OF EVIDENCE

Level 4.

DATA EXTRACTION

Search of literature yielded 32 studies for inclusion that involved 3112 soccer players after ACLR.

RESULTS

The overall graft failure/reoperation rate ranged between 3.0% and 24.8% (mean follow-up range, 2.3-10 years) and the combined ACL graft failure and contralateral ACL injury rate after initial ACLR was 1.0% to 16.7% (mean follow-up range, 3-10 years); a subgroup analysis for female and male players revealed a secondary ACL injury incidence rate of 27%, 95% CI (22%, 32%) and 10%, 95% CI (6%, 15%), respectively. Soccer players were able to return to play between 6.1 and 11.1 months and the majority of PROs showed favorable scores at medium-term follow-up.

CONCLUSION

Soccer players experience high ACL injury rates after primary ACLR and demonstrated similar reinjury rates as found in previous literature of athletes who participate in high-demand pivoting sports.

Comparison of Health Outcomes Over Time Among Women 1990-1991 Gulf War Veterans, Women 1990-1991 Gulf Era Veterans, and Women in the U.S. General Population

INTRODUCTION

The aim of this study is to examine health over almost 20 years of follow-up among women Gulf War veterans and women Gulf Era veterans and compare their health to that of women in the U.S. general population.

METHODS

We used data from a health survey of 1,274 women Gulf War veteran and Gulf Era veteran participants of the Gulf War Longitudinal Study who responded to all three waves. Data on the U.S. population of women came from the 1999-2000, 2005-2006, and 2011-2014 National Health and Nutrition Examination Survey (NHANES). Generalized estimating equations (GEEs) were used to compare the report of disease over time in women Gulf War and Gulf Era veterans. Differences in prevalence at the three survey timepoints were calculated between women Gulf War veterans and the NHANES women population, and women Gulf War Era veterans and the NHANES women population.

RESULTS

Women veterans who deployed to the 1990-1991 Gulf War report poorer health than women veterans who served during the same time but did not deploy. Women veterans reported a lower prevalence of hypertension, stroke, and diabetes than women in the NHANES sample. Women veterans also reported a higher prevalence of arthritis, chronic obstructive pulmonary disease, and skin cancer than women in the NHANES sample.

CONCLUSIONS

This study is the first to characterize the health of a population-based cohort of women Gulf War and women Gulf Era veterans over time and compare it with women's health in a civilian NHANES population. This demonstrates the value of epidemiological research on women veterans and the importance of developing longitudinal cohorts across genders.

All-cause and cause-specific mortality rates after severe extremity injuries among previously deployed active duty service members

BACKGROUND

Previous research has shown that active duty military personnel who sustain extremity injuries while in service are at elevated risk for serious physical and psychological health issues that could affect their long-term functioning and quality of life yet longer-term mortality has not been studied in this population.

OBJECTIVE

To determine whether rates of all-cause and cause-specific mortality are elevated for active duty U.S. service members who sustained traumatic limb injuries in service, compared to the broader population of deploying service members. To assess differences in mortality rates between service members with traumatic limb injuries that did versus did not result in amputation.

DESIGN

Retrospective cohort study; archival Department of Defense deployment, personnel, medical, and death records were combined and analyzed. Standardized mortality ratios (SMR) adjusted for age, sex, and ethnoracial group, along with associated 95% confidence intervals (CIs), were calculated to directly compare all-cause and cause-specific mortality rates in each of the two injury groups to rates in the total study population.

SETTING

Not applicable.

PARTICIPANTS

Service members who deployed in support of the global war on terror between 2001 and 2016 were eligible for inclusion; the final sample included 1,875,206 individuals surveilled through 2019.

INTERVENTION

Not applicable.

MAIN OUTCOME MEASURES

All-cause and cause-specific mortality rates.

RESULTS

Overall, the number of deaths was over three times higher than expected among service members with amputations (SMR = 3.01; CI: 2.36-3.65), and nearly two times higher among those with serious limb injuries not resulting in amputation (SMR = 1.72; CI: 1.54-1.90) when compared to the larger study population. Rates for both internal and external causes of death were significantly elevated among those with limb injuries.

CONCLUSIONS

Long-term mortality rates are elevated among service members with traumatic limb injuries, though mortality patterns may differ based on whether the injury results in amputation. Although further research into causal mechanisms is needed, these results may inform the development of interventions to improve long-term health outcomes among injured military personnel.

Partnerships to Facilitate Total Force Fitness

Total force fitness (TFF) is a multi-domain framework designed to assess, promote, and sustain human performance optimization across a service member's career arc. During the September 2021, TFF Summit sponsored by the Consortium for Health and Military Performance (CHAMP), a working group explored partnerships that could facilitate effective implementation and sustainment of TFF principles. Many potential partners were identified, both internal and external to the DoD. This report highlights some positions and organizations that provide the highest yield for successfully inculcating TFF across the services.

Predicting Postoperative Injury and Military Discharge Status After Knee Surgery in the US Army

BACKGROUND

Researchers have assessed postoperative injury or disability predictors in the military setting but typically focused on 1 type of surgical procedure at a time, used relatively small sample sizes, or investigated mixed cohorts with civilian populations.

PURPOSE

To identify the relationship between baseline variables and injury incidence or military discharge status in US Army soldiers after knee surgery.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Data were obtained from a repository containing personnel, performance, and medical records for all active-duty US Army soldiers. Multivariate logistic regressions were used to estimate the effects of numerous variables on postoperative injury or on medical discharge. Variable selection and model validation were conducted using the k-fold method.

RESULTS

A total of 7567 soldiers underwent knee surgery between 2017 and 2019. Meniscal procedures were the most common type of surgery (39%), and approximately 71% of the cohort had a postoperative injury. Significant predictors for sustaining a postoperative injury included having a previous nonknee injury (odds ratio [OR], 1.5), female sex (OR, 1.3), and Black race (OR, 1.2). Within 4 years after surgery, 17% of soldiers were discharged from the military because of knee-related disability. Significant predictors for discharge from duty included enlisted rank (OR, 2.3), recent fitness test failure (OR, 1.9), number of previous knee surgeries (OR, 1.7), and having a previous nonknee injury (OR, 1.6).

CONCLUSION

After knee surgery, nearly three-fourths of the soldiers in this cohort sustained a postoperative injury and almost one-fifth of soldiers were medically discharged from the military within 4 years. This study identified variables that indicate statistically increased risk for these postoperative outcomes and highlighted potentially modifiable factors.

Cellular Cytosolic Energy Replenishment Increases Vascularized Composite Tissue Tolerance to Extended Cold Ischemia Time

BACKGROUND

Vascularized composite allotransplantation (VCA) is a restorative surgical procedure to treat whole or partially disfiguring craniofacial or limb injuries. The routine clinical use of this VCA surgery is limited using compromised allografts from deceased donors and by the failure of the current hypothermic preservation protocols to extend the allograft's cold ischemia time beyond 4 h. We hypothesized that the active replenishment of the cellular cytosolic adenosine-5`-triphosphate (ATP) stores by means of energy delivery vehicles (ATPv) encapsulating high-energy ATP is a better strategy to improve allograft's tolerance to extended cold ischemia times.

MATERIALS AND METHODS

We utilized established rat model of isolated bilateral in-situ non-cycled perfusions of both hind limbs. Ipsilateral and contralateral limbs in the anesthetized animal were randomized for simultaneous perfusions with either the University of Wisconsin (UW) solution, with/without O2 supplementation (control), or with the UW solution supplemented with the ATPv, with/without O2 supplementation (experimental). Following perfusion, the hind limbs were surgically removed and stored at 4°C for 12, 16, or 24 hours as extended cold ischemia times. At the end of each respective storage time, samples of skin, and soleus, extensor digitalis longus, and tibialis anterior muscles were recovered for assessment using tissue histology and tissue lysate studies.

RESULTS

Control muscle sections showed remarkable microvascular and muscle damage associated with loss of myocyte transverse striation and marked decrease in myocyte nucleus density. A total of 1,496 nuclei were counted in 179 sections of UW-perfused control muscles in contrast to 1,783 counted in 130 sections of paired experimental muscles perfused with the ATPv-enhanced perfusate. This yielded 8 and 13 nuclei/field for the control and experimental muscles, respectively (P < .004). Oxygenation of the perfusion solutions before use did not improve the nucleus density of either the control or experimental muscles (n = 7 animals, P > .05). Total protein isolated from the muscle lysates was similar in magnitude regardless of muscle type, perfusion protocol, or duration of cold ischemia time. Prolonged static cold preservation of the hind limbs completely degraded the composite tissue's Ribonucleic acid (RNA). This supplementary result confirms the notion that that reverse transcription-Polymerase Chain Reaction, enzyme-linked immunosorbent assay, or the respiratory complex II enzyme activity techniques should not be used as indices of graft quality after prolonged static cold storage.

CONCLUSIONS

In conclusion, this study demonstrates that active cellular cytosolic ATP replenishment increases hind limb composite tissue tolerance to extended cold ischemia times. Quality indicators and clinically relevant biomarkers that define composite tissue viability and function during static cold storage are warranted.

Comparison of Finger, Hand, and Wrist Injuries in the US Air Force to US Workers

OBJECTIVE

Fingers, hands, and wrists (FHW) are the most frequently injured body parts in work-related injuries. This study described and compared FHW injuries among enlisted, officer, and civilian US Air Force (USAF) personnel to those in the US workforce.

METHODS

All work-related, noncombat FHW injuries (≥1 lost workday) and demographics among USAF personnel and US workforce (2008-2018) were included. The USAF FHW injury rates were age adjusted to the US employment and compared by sex, source, event, and nature of the injuries.

RESULTS

Finger, hand, and wrist injuries were significantly lower among the USAF personnel and among females. In both populations, FHW injuries from falls were higher and increased with age group among females. Males had higher overall FHW injuries from contact with objects and equipment.

CONCLUSIONS

Prevention efforts should focus on understanding risk factors and sharing successful prevention activities.

Association of Traumatic Knee Injury With Radiographic Evidence of Knee Osteoarthritis in Military Officers

OBJECTIVE

The association between knee injury and knee osteoarthritis (OA) is understudied relative to its importance, particularly in younger populations. This study was undertaken to examine the association of knee injury with radiographic features of knee OA in military officers, who have a physically demanding profession and high rates of knee injury.

METHODS

Participants were recruited in 2015-2017 from an existing program that enrolled 6,452 military officers during 2004-2009. Officers with a history of knee ligament or meniscal injuries (n = 117 via medical record review) were compared to officers with no history of knee injury (n = 143). Bilateral posteroanterior knee radiographs were obtained using a standardized fixed-flexion positioning frame. All images were read for Kellgren/Lawrence (K/L) grade, osteophyte (OST), and joint space narrowing (JSN) scores. Data were analyzed using linear-risk regression models with generalized estimating equations.

RESULTS

Injured and noninjured participants were similar (mean age 28 years, mean body mass index 25 kg/m2 , ~40% female). The mean time from first knee injury to imaging among injured participants was 9.2 years. Compared with noninjured knees, greater prevalence of radiographic OA (K/L grade ≥ 2), OST (grade ≥ 1), and JSN (grade ≥ 1) was observed among injured knees, with prevalence differences of +16% (95% confidence interval [95% CI] 10%, 22%), +29% (95% CI 20%, 38%), and + 17% (95% CI 10%, 24%), respectively. Approximately 1 in 6 officers with prior knee injury progressed to radiographic OA by age 30 years.

CONCLUSION

At the midpoint of a projected 20-year military career, officers with a history of traumatic knee injury have a markedly increased prevalence of knee radiographic OA compared to officers without injury.

Increased Barefoot Stride Variability Might Be Predictor Rather than Risk Factor for Overuse Injury in the Military

Footwear usage could be a promising focus in reducing musculoskeletal injury risk in lower extremities commonly observed among the military. The goal of this research was to find potential gait-related risk factors for lower leg overuse injuries. Cases (n = 32) were active-duty infantry soldiers who had suffered an overuse injury in the previous six months of service before enrolling in the study. The control group (n = 32) included infantry soldiers of the same age and gender who did not have a history of lower leg overuse injury. In the gait laboratory, individuals were asked to walk on a 5-m walkway. Rearfoot eversion, ankle plantar/dorsiflexion and stride parameters were evaluated for barefoot and shod conditions. Barefoot walking was associated with higher stride time variability among cases. According to the conditional regression analysis, stride time variability greater than 1.95% (AUC = 0.77, 95% CI (0.648 to 0.883), p < 0.001) during barefoot gait could predict lower leg overuse injury. Increased barefoot gait variability should be considered as a possible predictive factor for lower leg overuse injury in the military, and gait with military boots masked stride-related differences between soldiers with and without lower leg overuse injury.

Factors Associated With Neuromusculoskeletal Injury and Disability in Navy and Marine Corps Personnel

INTRODUCTION

Neuromusculoskeletal injuries (NMSKI) are very common in the military, which contribute to short- and long-term disability.

MATERIALS AND METHODS

Population-level NMSKI, limited duty (LIMDU), and long-term disability episode counts in the U.S. Navy (USN) and U.S. Marine Corps (USMC) from December 2016 to August 2021 were extracted from the Musculoskeletal Naval Epidemiological Surveillance Tool. The incidence of NMSKI, LIMDU, and long-term disability was calculated. A hurdle negative binomial regression evaluated the association of body region, sex, age, rank, age by rank, and service branch on NMSKI, LIMDU, and long-term disability incidence.

RESULTS

From December 2016 to August 2021, there were 2,004,196 NMSKI episodes (USN: 3,285/1,000 Sailors; USMC: 4,418/1,000 Marines), 16,791 LIMDU episodes (USN: 32/1,000 Sailors; USMC: 29/1,000 Marines), and 2,783 long-term disability episodes (USN: 5/1,000 Sailors; USMC: 5/1,000 Marines). There was a large-magnitude protective effect on NMSKI during the pandemic (relative risk, USN: 0.70; USMC: 0.75). Low back and ankle-foot were the most common, primarily affecting female personnel, aged 25-44 years, senior enlisted, in the USMC. Shoulder, arm, pelvis-hip, and knee conditions had the greatest rates of disability, with female sex, enlisted ranks, aged 18-24 years, and service in the USMC having the most salient risk factors.

CONCLUSION

Body region, sex, age, rank, and branch were the salient factors for NMSKI. The significant protective effect during the pandemic was likely a function of reduced physical exposure and limited access to nonurgent care. Geographically accessible specialized care, aligned with communities with the greatest risk, is needed for timely NMSKI prevention, assessment, and treatment.

Musculoskeletal Injuries at the Chinese Peacekeeping Level II Hospital in Wau, South Sudan, 2018-2022

INTRODUCTION

Musculoskeletal injuries (MSIs) are common among U.N. military personnel and cause a substantial toll, but little is known about the actual risks and changes of MSIs. The Chinese level II hospital (CHN L2H) was the highest-level hospital in the Western Sector of the U.N. Mission in South Sudan (UNMISS). This study reviewed and analyzed the MSIs managed by the CHN L2H in UNMISS.

METHODS

Medical records of MSIs in CHN L2H from September 2018 to July 2022 were identified. We analyzed all the MSIs and treatment procedures.

RESULTS

A total of 857 patients from more than 40 countries were included (86.8% men, average age of 37.83 years), consisting of 457 troop-contributing country, 231 U.N. local, and 169 U.N. international personnel. The most common injury was lumbar muscle strain (14.2%). Sports-related mechanism (29.2%) was the most frequent cause of MSIs. The most significant proportions of anatomical regions were the lumbar spine (22.52%), hand (13.77%), and foot (10.97%). No-steroid anti-inflammatory drugs (43.99%), physical therapy (20.54%), and immobilization (11.32%) were the most used treatments.

CONCLUSIONS

MSIs are common diseases in the CHN L2H in the Western Sector of UNMISS. The universality and complexity of MSIs demonstrate the urgent need to improve prevention, treatment, and rehabilitation.

Musculoskeletal Injury Risk Stratification: A Traffic Light System for Military Service Members

Risk factor identification is a critical first step in informing musculoskeletal injury (MSKI) risk mitigation strategies. This investigation aimed to determine if a self-reported MSKI risk assessment can accurately identify military service members at greater MSKI risk and determine whether a traffic light model can differentiate service members' MSKI risks. A retrospective cohort study was conducted using existing self-reported MSKI risk assessment data and MSKI data from the Military Health System. A total of 2520 military service members (2219 males: age 23.49 ± 5.17 y, BMI 25.11 ± 2.94 kg/m²; and 301 females: age 24.23 ± 5.85 y, BMI 25.59 ± 3.20 kg/m², respectively) completed the MSKI risk assessment during in-processing. The risk assessment consisted of 16 self-report items regarding demographics, general health, physical fitness, and pain experienced during movement screens. These 16 data points were converted to 11 variables of interest. For each variable, service members were dichotomized as at risk or not at risk. Nine of the 11 variables were associated with a greater MSKI risk and were thus considered as risk factors for the traffic light model. Each traffic light model included three color codes (i.e., green, amber, and red) to designate risk (i.e., low, moderate, and high). Four traffic light models were generated to examine the risk and overall precision of different cut-off values for the amber and red categories. In all four models, service members categorized as amber [hazard ratio (HR) = 1.38-1.70] or red (HR = 2.67-5.82) were at a greater MSKI risk. The traffic light model may help prioritize service members who require individualized orthopedic care and MSKI risk mitigation plans.

Musculoskeletal injuries in US Air Force Tactical Air Control Party trainees: an 11-year longitudinal retrospective cohort study and presentation of a musculoskeletal injury classification matrix

INTRODUCTION

Little is known of the epidemiology of musculoskeletal injuries (MSKIs) in US Air Force Special Warfare (AFSPECWAR) Tactical Air Control Party trainees. The purpose of this longitudinal retrospective cohort study was to (1) report the incidence and type of MSKI sustained by AFSPECWAR trainees during and up to 1 year following training, (2) identify factors associated with MSKI, and (3) develop and present the MSKI classification matrix used to identify and categorise injuries in this study.

METHODS

Trainees in the Tactical Air Control Party Apprentice Course between fiscal years 2010-2020 were included. Diagnosis codes were classified as MSKI or non-MSKI using a classification matrix. Incidence rates and incidence proportion for injury types and regions were calculated. Measures were compared for differences between those who did and did not sustain an MSKI during training. A Cox proportional hazards model was used to identify factors associated with MSKI.

RESULTS

Of the 3242 trainees, 1588 (49%) sustained an MSKI during training and the cohort sustained MSKIs at a rate of 16 MSKI per 100 person-months. Overuse/non-specific lower extremity injuries predominated. Differences were seen in some baseline measures between those who did and did not sustain an MSKI. Factors retained in the final Cox regression model were age, 1.5-mile run times and prior MSKI.

CONCLUSION

Slower run times and higher age were associated with an increased likelihood of MSKI. Prior MSKI was the strongest predictor of MSKI during training. Trainees sustained MSKIs at a higher rate than graduates in their first year in the career field. The MSKI matrix was effective in identifying and categorising MSKI over a prolonged (12-year) surveillance period and could be useful for future injury surveillance efforts in the military or civilian settings. Findings from this study could inform future injury mitigation efforts in military training environments.

Wearable technology assessing running biomechanics and prospective running-related injuries in Active Duty Soldiers

The purpose of this study was to determine if running biomechanical variables measured by wearable technology were prospectively associated with running injuries in Active Duty Soldiers. A total of 171 Soldiers wore a shoe pod that collected data on running foot strike pattern, step rate, step length and contact time for 6 weeks. Running-related injuries were determined by medical record review 12 months post-study enrollment. Differences in running biomechanics between injured and non-injured runners were compared using independent t-tests or ANCOVA for continuous variables and chi-square analyses for the association of categorical variables. Kaplan-Meier survival curves were used to estimate the time to a running-related injury. Risk factors were carried forward to estimate hazard ratios using Cox proportional hazard regression models. Forty-one participants (24%) sustained a running-related injury. Injured participants had a lower step rate than non-injured participants, but step rate did not have a significant effect on time to injury. Participants with the longest contact time were at a 2.25 times greater risk for a running-related injury; they were also relatively slower, heavier, and older. Concomitant with known demographic risk factors for injury, contact time may be an additional indicator of a running-related injury risk in Active Duty Soldiers.

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.

Safe Administration and Low Healthcare Utilization Following Musculoskeletal Corticosteroid Injections by U. S. Military Physical Therapists

INTRODUCTION

Musculoskeletal (MSK) injuries make up a significant proportion of conditions treated by military healthcare providers during wartime. Though many common MSK injuries may benefit from corticosteroid injection (CSI), a shortage of qualified military clinicians has led to diminished access to appropriate care. Longer wait times to receive treatment pose detrimental effects on military readiness and have garnered the attention of military leaders. One solution was the development of advanced training for United States Air Force physical therapists (USAF PTs) to gain clinical privileges in administering CSI. The objectives of this study were to determine in USAF PTs (1) the prevalence of those with privileges to administer CSI; (2) the type and (3) safety of MSK CSI administered; (4) incidence of CSI complications; (5) healthcare utilization following CSI; and (6) barriers to obtaining and practicing CSI privileges.

MATERIALS AND METHODS

United States Air Force PTs with CSI privileges received instructions to follow a link to an anonymous Google survey. Electronic medical record reviews were conducted by three USAF PTs to determine the occurrence and severity of CSI complications provided by USAF PTs and advanced healthcare providers (AHPs). The principal investigator conducted further review of the patients' electronic medical records to calculate healthcare utilization following CSI administered by USAF PTs. A hospital administrator selected cases of similar diagnoses treated with CSI by USAF AHPs. The number selected cases treated by AHPs are similar to the number of CSI cases treated by USAF PTs.

RESULTS

Eleven USAF PTs held CSI privileges. No major complications associated with CSI were recorded. Of the 95 CSI cases treated by USAF PTs, 27 (28.4%) reported increased pain compared to 24 (27.9%) of 86 CSI cases treated by AHPs (P = .94). Healthcare utilization for the number of follow-up visits, imaging, and additional laboratory tests following CSI by USAF PTs was lower compared to AHPs (chi-square; P < .0069).

CONCLUSION

Nine percentage of USAF PTs held CSI privileges. United States Air Force PTs were equally safe as AHPs who administered CSI and associated with a lower rate of healthcare utilization following the intervention. Training USAF PTs to administer CSI could be the standard for all USAF PTs who meet qualification requirements. Adoption of similar training and credentialing policies for civilian PTs warrants further exploration.

Prevention of Lower Extremity Musculoskeletal Injuries in Tactical and First Responder Populations: A Systematic Review and Meta-Analysis of Randomized Trials From 1955 to 2020

ABSTRACT

Sinnott, AM, Krajewski, KT, LaGoy, AD, Beckner, ME, Proessl, F, Canino, MC, Nindl, BC, Turner, RL, Lovalekar, MT, Connaboy, C, and Flanagan, SD. Prevention of lower extremity musculoskeletal injuries in tactical and first responder populations: A systematic review and meta-analysis of randomized trials from 1955 to 2020. J Strength Cond Res 37(1): 239-252, 2023-Lower extremity musculoskeletal injuries (LEMSIs) impose a significant burden on tactical and first responder populations. To determine the effectiveness of LEMSI prevention strategies, we performed a systematic review and meta-analysis of randomized controlled trials published in English from 1955 to 2020 (PROSPERO: CRD42018081799). MEDLINE, EMBASE, Cochrane, CINAHL, ProQuest, and DTIC databases were searched for trials that assigned military service members, police, firefighters, or paramedics to LEMSI prevention interventions with a minimum surveillance period of 12 weeks. Evidence was synthesized as odds ratios (OR) for LEMSI occurrence between individuals assigned to interventions and those assigned to standard activities. Risk of bias was assessed with the Cochrane Risk of Bias tool 2.0. Random-effects meta-analyses were conducted for (a) physical training and (b) footwear modifications to reduce LEMSI and (c) footwear modifications to reduce stress fractures specifically. Certainty in the body of evidence was determined with the GRADE approach. Of 28,499 records, 18 trials comprised of more than 11,000 subjects were synthesized. Interventions included physical training (8, N = 6,838), footwear modifications (8, N = 3,792), nutritional supplementation (1, N = 324), and training modifications (1, N = 350). Overall risk of bias was generally moderate ( N = 7 of 18) or high ( N = 9 of 18). Physical training (OR = 0.87, 95% CI [0.71, 1.08], p = 0.22, I 2 = 58.4%) and footwear modification (OR = 1.13, 95% CI [0.85, 1.49], p = 0.42, I 2 = 0.0%) did not reduce LEMSI or stress fractures (OR = 0.76, 95% CI [0.45, 1.28], p = 0.30, I 2 = 70.7%). Our results indicate that there is weak evidence to support current LEMSI prevention strategies. Future efforts will benefit from longer surveillance periods, assessment of women and nonmilitary populations, improved methodological rigor, and a greater breadth of approaches.

Iron deficiency and high-intensity running interval training do not impact femoral or tibial bone in young female rats

In the USA, as many as 20 % of recruits sustain stress fractures during basic training. In addition, approximately one-third of female recruits develop Fe deficiency upon completion of training. Fe is a cofactor in bone collagen formation and vitamin D activation, thus we hypothesised Fe deficiency may be contributing to altered bone microarchitecture and mechanics during 12-weeks of increased mechanical loading. Three-week old female Sprague Dawley rats were assigned to one of four groups: Fe-adequate sedentary, Fe-deficient sedentary, Fe-adequate exercise and Fe-deficient exercise. Exercise consisted of high-intensity treadmill running (54 min 3×/week). After 12-weeks, serum bone turnover markers, femoral geometry and microarchitecture, mechanical properties and fracture toughness and tibiae mineral composition and morphometry were measured. Fe deficiency increased the bone resorption markers C-terminal telopeptide type I collagen and tartate-resistant acid phosphatase 5b (TRAcP 5b). In exercised rats, Fe deficiency further increased bone TRAcP 5b, while in Fe-adequate rats, exercise increased the bone formation marker procollagen type I N-terminal propeptide. In the femur, exercise increased cortical thickness and maximum load. In the tibia, Fe deficiency increased the rate of bone formation, mineral apposition and Zn content. These data show that the femur and tibia structure and mechanical properties are not negatively impacted by Fe deficiency despite a decrease in tibiae Fe content and increase in serum bone resorption markers during 12-weeks of high-intensity running in young growing female rats.

Meeting the complex healthcare needs of veterans

ABSTRACT

More than half of US veterans seek care outside of the Veterans Health Administration. Physical and mental healthcare needs can be complicated by experiences during military service. Community clinicians can deliver more holistic and comprehensive care to veterans through understanding the unique needs of the veteran population.

Intra-articular injection of flavopiridol-loaded microparticles for treatment of post-traumatic osteoarthritis

Rapid joint clearance of small molecule drugs is the major limitation of current clinical approaches to osteoarthritis and its subtypes, including post-traumatic osteoarthritis (PTOA). Particulate systems such as nano/microtechnology could provide a potential avenue for improved joint retention of small molecule drugs. One drug of interest for PTOA treatment is flavopiridol, which inhibits cyclin-dependent kinase 9 (CDK9). Herein, polylactide-co-glycolide microparticles encapsulating flavopiridol were formulated, characterized, and evaluated as a strategy to mitigate PTOA-associated inflammation through the inhibition of CDK9. Characterization of the microparticles, including the drug loading, hydrodynamic diameter, stability, and release profile was performed. The mean hydrodynamic diameter of flavopiridol particles was ∼15 µm, indicating good syringeability and low potential for phagocytosis. The microparticles showed no cytotoxicity in-vitro, and drug activity was maintained after encapsulation, even after prolonged exposure to high temperatures (60 °C). Flavopiridol-loaded microparticles or blank (unloaded) microparticles were administered by intraarticular injection in a rat knee injury model of PTOA. We observed significant joint retention of flavopiridol microparticles compared to the soluble flavopiridol, confirming the sustained release behavior of the particles. Matrix metalloprotease (MMP) activity, an indicator of joint inflammation, was significantly reduced by flavopiridol microparticles 3 days post-injury. Histopathological analysis showed that flavopiridol microparticles reduced PTOA severity 28 days post-injury. Taken altogether, this work demonstrates a promising biomaterial platform for sustained small molecule drug delivery to the joint space as a therapeutic measure for post-traumatic osteoarthritis. STATEMENT OF SIGNIFICANCE: Post-traumatic osteoarthritis (PTOA) begins with the deterioration of subchondral bone and cartilage after acute injuries. In spite of the prevalence of PTOA and its associated financial and psychological burdens, therapeutic measures remain elusive. A number of small molecule drugs are now under investigation to replace FDA-approved palliative measures, including cyclin-dependent kinase 9 (CDK9) inhibitors which work by targeting early inflammatory programming after injury. However, the short half-life of these drugs is a major hurdle to their success. Here, we show that biomaterial encapsulation of Flavopiridol (CDK9 inhibitor) in poly (lactic-co-glycolic acid) microparticles is a promising route for direct delivery and improved drug retention time in the knee joint. Moreover, administration of the flavopiridol microparticles reduced the severity of PTOA.

Military service branch differences in alcohol use, tobacco use, prescription drug misuse, and mental health conditions

INTRODUCTION

Rates of substance use and mental health conditions vary across military service branches, yet branches also differ notably in terms of demographics and deployment experiences. This study examines whether branch differences in substance use and mental health outcomes persist after adjustment for a comprehensive set of demographic and deployment-related factors.

METHODS

Data on 16,699 Armed Forces Active Duty service members were from the 2015 Department of Defense Health Related Behaviors Survey. Service branch-specific prevalences were estimated for self-reports of heavy episodic drinking (HED), possible alcohol use disorder (AUD), current smoking, e-cigarette use, smokeless tobacco use, prescription drug misuse, probable post-traumatic stress disorder (PTSD), probable depression, and probable anxiety. Using logistic regression, we assessed whether branch differences persisted after adjusting for an extensive array of demographic factors (among full sample) and deployment/combat factors (among ever-deployed subgroup).

RESULTS

HED, AUD, smoking, e-cigarette use, smokeless tobacco use, depression, and anxiety were highest in the Marine Corps; prescription drug misuse and PTSD were highest in the Army. HED, AUD, smoking, smokeless tobacco use, PTSD, depression, and anxiety were lowest in the Air Force; e-cigarette use and prescription drug misuse were lowest in the Coast Guard. Demographics and deployment/combat experiences differed across branches. After adjustment, service members in the Army, Marine Corps and Navy exhibited nearly 2-3 times the odds of multiple mental health conditions and substance use behaviors relative to the Air Force.

CONCLUSION

Service branch differences were not fully explained by variation in demographics and deployment/combat experiences.

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.

The Use of Force Plate Vertical Jump Scans to Identify Special Warfare Trainees at Risk for Musculoskeletal Injury: A Large Cohort Study

BACKGROUND

Vertical jump scans from commercially available force plate systems are increasingly used in military settings to screen for musculoskeletal injury (MSKI) risk. However, to date, no studies have determined the ability of these tools to identify tactical athletes at elevated risk for MSKI.

PURPOSE

To (1) determine associations between scores from a force plate vertical jump test and the likelihood of experiencing an MSKI and to (2) establish the test-retest reliability of the output scores from the force plate system used.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A total of 823 male Air Force Special Warfare trainees underwent force plate vertical jump screenings before entering an 8-week training course at US Air Force Special Warfare Training Wing. MSKI data were collected for the 8-week surveillance period for each trainee. Logistic regression analyses were used to identify associations between baseline force plate jump scores and the likelihood of MSKI (any region) or a lower extremity MSKI (significance level, P = .05). The test-retest portion of the study collected force plate output scores from 12 trainees performing 3 trials of the standard test procedures. The reliability of 5 output scores was assessed with intraclass correlation coefficients (ICCs) using a single rater.

RESULTS

All force plate output scores demonstrated excellent test-retest reliability (ICC >0.90). Overall 308 (36.4%) trainees had an MSKI during the surveillance period. However, no significant associations were found between the proprietary force plate vertical jump scan output scores and the likelihood of experiencing either an MSKI or a lower extremity MSKI.

CONCLUSION

Output scores from this commercially available force plate system did not identify Air Force Special Warfare trainees at elevated risk of experiencing an MSKI.

Test-Retest Reliability and Translation of the Musculoskeletal Screening Protocol Questionnaire Used in the Swedish Armed Forces

INTRODUCTION

Musculoskeletal disorders (MSDs) in military personnel are common, and it is important to identify those at risk so that appropriate preventive and rehabilitative strategies can be undertaken. The Musculoskeletal Screening Protocol (MSP) questionnaire is part of the implemented prevention strategy to reduce MSDs in the Swedish Armed Forces. The aims of this study were to evaluate the questionnaire's reliability and to translate it into English.

MATERIALS AND METHODS

One-week test-retest reliability of the questionnaire was evaluated in a sample of 35 Swedish military personnel. Reliability was evaluated by calculations of Cohen's kappa or quadratic-weighted kappa. Percent agreement was used as a parameter for measurement error. Translation into English included forward and backward translations and expert committee discussions.

RESULTS

Kappa values relating to physical complaints/injuries were excellent (>0.75) except for knee and lower leg MSDs and for the intensity ratings, where Kappa values were mostly interpreted as fair-to-good (0.4-0.75). Kappa values of items pertaining physical performance, physical activity and exercise, eating and tobacco habits, sleep, and perceived health ranged between 0.72 and 1. Kappa values for feeling mentally or physical prepared were 0.47 and 0.65, respectively. Most percentage agreement values ranged between 90% and 100%. The English version was found to be satisfactorily equivalent to the Swedish MSP questionnaire.

CONCLUSION

The Swedish MSP questionnaire was found to be highly reliable and was satisfactorily translated into English. This provides support for the questionnaire's ability to trustworthily capture the prevalence of MSDs and perceived health in military personnel. Future research is warranted on the psychometric properties of the English MSP questionnaire.

An Essential Guide to Chiropractic in the United States Military Health System and Veterans Health Administration

OBJECTIVE

The purpose of this article is to provide an essential overview of chiropractic services in United States military and veterans' health care systems.

METHODS

We reviewed literature, legislation, and policies from 1936 through September 2021 pertaining to chiropractic services in the United States military and veterans' health systems. Using these sources and our combined experience in these systems, we identified fundamental themes in the delivery of chiropractic care in the health care systems of the Department of Defense (providing health care for active duty service members) and the Department of Veterans Affairs (providing health care for veterans) in main topic areas.

RESULTS

We identified 7 main topic areas relevant to the 2 systems: populations served by chiropractors; health care systems; integration; utilization and supply of chiropractic care; vetting of chiropractors; roles and evaluation of chiropractors; and oversight and leadership. Key information about chiropractic care in these systems was synthesized into the main topic areas. Benefits of high-quality within-system chiropractic care to active-duty service members and veterans are presented. The assets that within-system chiropractors bring to the Department of Defense and Department of Veterans Affairs health care systems are discussed for each main topic area.

CONCLUSION

This article contains an essential overview of chiropractic services in the Department of Defense and the Department of Veterans Affairs. It offers clarity regarding the integration of chiropractic services into these health care systems and includes a 1-page brief of talking points that may help better inform ongoing discussions of chiropractic services in these 2 different but intertwined environments.

Gait biomechanics: A clinically relevant outcome measure for preclinical research of musculoskeletal trauma

Traumatic injuries to the musculoskeletal system are the most prevalent of those suffered by United States Military Service members and accounts for two-thirds of initial hospital costs to the Department of Defense. These combat-related wounds often leave survivors with life-long disability and represent a significant impediment to the readiness of the fighting force. There are immense opportunities for the field of tissue engineering and regenerative medicine (TE/RM) to address these musculoskeletal injuries through regeneration of damaged tissues as a means to restore limb functionality and improve quality of life for affected individuals. Indeed, investigators have made promising advancements in the treatment for these injuries by utilizing small and large preclinical animal models to validate therapeutic efficacy of next-generation TE/RM-based technologies. Importantly, utilization of a comprehensive suite of functional outcome measures, particularly those designed to mimic data collected within the clinical setting, is critical for successful translation and implementation of these therapeutics. To that end, the objective of this review is to emphasize the clinical relevance and application of gait biomechanics as a functional outcome measure for preclinical research studies evaluating the efficacy of TE/RM therapies to treat traumatic musculoskeletal injuries. Specifically, common musculoskeletal injuries sustained by service members-including volumetric muscle loss, post-traumatic osteoarthritis, and composite tissue injuries-are examined as case examples to highlight the use of gait biomechanics as an outcome measure using small and large preclinical animal models.

Longitudinal study of medical downgrades in the Royal Air Force

INTRODUCTION

As the focus of the Royal Air Force (RAF) shifts from sustained to contingency operations and the number of personnel is reduced, the burden of retained, medically downgraded personnel may affect operational readiness. The main aims were: to define the prevalence of morbidity leading to permanent medical downgrading; to determine at risk populations and identify areas for improvement.

METHOD

Database of personnel referred to the RAF Medical Board was analysed from January 2012 to October 2013 and January 2017 to December 2019. Patients were excluded if they did not require a formal medical board; incomplete and duplicate entries were also excluded. The primary reason for medical downgrade was categorised with an ICD-10 code. Further subanalysis compared musculoskeletal disease with age, individual trade groups and anatomic region.

RESULTS

2% of RAF service personnel were permanently downgraded annually. Musculoskeletal disease was the leading cause for permanent downgrade across both periods: 58% and 49%. Female personnel were at a greater risk of musculoskeletal downgrade compared with males. Spinal and knee pathology were the leading cause for downgrading among 'high risk' personnel. Personnel downgraded due to musculoskeletal pathology were often retained in a limited role with 10% and 5% retained as medically fully deployable. 14% and 12% of personnel downgraded due to musculoskeletal pathology were medically discharged.

CONCLUSION

Musculoskeletal disease was the leading cause for permanent medical downgrades in the RAF. A greater proportion of downgraded personnel with musculoskeletal conditions were retained in service with medical limitations rather than medically discharged.

Point-of-Care Tomosynthesis Imaging of the Wrist

INTRODUCTION

Musculoskeletal injury to extremities is a common issue for both stateside and deployed military personnel, as well as the general public. Superposition of anatomy can make diagnosis difficult using standard clinical techniques. There is a need for increased diagnostic accuracy at the point-of-care for military personnel in both training and operational environments, as well as assessment during follow-up treatment to optimize care and expedite return to service. Orthopedic tomosynthesis is rapidly emerging as an alternative to digital radiography (DR), exhibiting an increase in sensitivity for some clinical tasks, including diagnosis and follow-up of fracture and arthritis. Commercially available digital tomosynthesis systems are large complex devices. A compact device for extremity tomosynthesis (TomoE) was previously demonstrated using carbon nanotube X-ray source array technology. The purpose of this study was to prepare and evaluate the prototype device for an Institutional Review Board-approved patient wrist imaging study and provide initial patient imaging results.

MATERIALS AND METHODS

A benchtop device was constructed using a carbon nanotube X-ray source array and a flat panel digital detector. Twenty-one X-ray projection images of cadaveric specimens and human subjects were acquired at incident angles from -20 to +20 degrees in various clinical orientations, with entrance dose calibrated to commercial digital tomosynthesis wrist scans. The projection images were processed with an iterative reconstruction algorithm in 1 mm slices. Reconstruction slice images were evaluated by a radiologist for feature conspicuity and diagnostic accuracy.

RESULTS

The TomoE image quality was found to provide more diagnostic information than DR, with reconstruction slices exhibiting delineation of joint space, visual conspicuity of trabecular bone, bone erosions, fractures, and clear depiction of normal anatomical features. The scan time was 15 seconds and the skin entrance dose was verified to be 0.2 mGy.

CONCLUSIONS

The TomoE device image quality has been evaluated using cadaveric specimens. Dose was calibrated for a patient imaging study. Initial patient images depict a high level of anatomical detail and an increase in diagnostic value compared to DR.

Prevalence of Musculoskeletal Injuries in a Security Force Assistance Brigade Before, During, and After Deployment

INTRODUCTION

The Security Force Assistance Brigades (SFABs) are specialized units designed to strengthen allied and partnered nations through advising, supporting, liaising, and assessing in support of U.S. national security interests and combatant commanders' war fighting objectives. As the 1st SFAB was the pioneer unit, descriptive analysis of the musculoskeletal injures and body regions occurring before, during, and after deployment was previously unavailable, limiting the ability of embedded holistic health and fitness teams to proactively address the unit's musculoskeletal needs and medical readiness.

MATERIALS AND METHODS

Physical therapists collected and retrospectively analyzed data from 4597 encounters over 19 months: 4 months before, 9 months during, and 4 months after deployment using descriptive statistics.

RESULTS

Physical therapy encounters averaged 124 per month during pre-deployment preparation, 363 per month during deployment, and 206 per month post-deployment. The most common musculoskeletal injuries identified during pre-deployment were to the lumbar spine (31.8%), knee (18.1%), and shoulder (9.1%). The most common areas of injury during deployment were to the lumbar spine (28.4%), thoracic spine (18.3%), and shoulder (14.0%). The most common post-deployment injuries consulted were to the lumbar spine (21.3), shoulder (19.6%), and knee (17.8%).

CONCLUSION

Musculoskeletal injuries are a concern that may limit medical readiness in the SFABs in the time of before, during, and after deployment. Low back pain is the primary musculoskeletal injury of the 1st SFAB throughout the entire deployment cycle. Based on these findings, recommendations include embedding injury prevention programs to address low back pain to improve medical readiness. More research is required to assess the effectiveness of these programs in reducing incidents of musculoskeletal injuries before, during, and after deployment cycles.

Shoulder Pain of Spinal Source in the Military: A Case Series

Musculoskeletal injury (MSI) presents the greatest threat to military mission readiness. Atraumatic shoulder pain is a common military MSI that often results in persistent functional limitations. Shoulder orthopedic evaluation presents many diagnostic challenges, due in part to the possibility of a spinal source of symptoms. This case series outlines the use of mechanical diagnosis and therapy to screen the cervical and thoracic spine in active duty (AD) service members (SMs) with a chief complaint of unchanging or worsening shoulder pain. All three SMs previously received shoulder-specific diagnoses from experienced clinicians, yet repeated movements revealed a possible spinal nociceptive driver that guided targeted intervention. Treatment directed only at the cervical spine resulted in a clinically important improvement within an average of 10 days from the initial evaluation, return to duty (RTD) within an average of 32 days, and continued resolution at 3 months. SMs can independently complete the screening process with guidance from healthcare providers, ultimately shaping the treatment strategy and possibly facilitating self-management of future recurrence. This case series demonstrates that identification of shoulder pain of spinal source in the military population may be an important step in facilitating timely RTD. These cases also highlight the use of a standardized, systematic method to screen the cervical and thoracic spine that concurrently reveals the indicated treatment. Further research to determine the prevalence of shoulder pain of spinal source in the AD population and its impact on RTD rates has the potential to reduce the substantial burden of MSI in the military.

"To Conserve Fighting Strength": The Role of Military Culture in the Delivery of Care

Introduction

There are ongoing discussions about reorganizing the delivery of health care within the US Armed Forces. The military cultural context of care has beneficial qualities for patients with orthopedic and extremity trauma acquired during deployments to conflict zones.

Methods

The study included 35 participants with lower limb amputations who had been discharged from the Amputee Patient Care Program ≥ 12 months prior to the study. Participants were interviewed using a lightly structured schedule designed to elicit accounts of community integration, which attended to reports of belongingness supported by accounts of social engagement in work, school, family, and social events. Interviews were analyzed using a modified content analysis approach.

Results

Participants generally described their postcare lives as "successful" that had been built on "good outcomes." For most former patients, remembering the social intensity of their rehabilitation program was an important element in their narratives of recovery. Weekly amputee clinics worked to alleviate stress and anxiety in participants' minds around the complexities of their injuries and care.

Conclusions

Participants reported that features of their care were particularly valuable to their recovery and their current assessment of their injury related health. These features are present, in part because of the military cultural context that is part of the framework of care delivery.

Spinal cord injury in the United States Army Special Forces

OBJECTIVE

Spinal cord injury (SCI) is an area of key interest in military medicine but has not been studied among the US Army Special Forces (SF), the most elite group of US soldiers. SF soldiers make up a disproportionate 60% of all Special Operations casualties. The objective of this study was to better understand SCI incidence in the SF, its mechanisms of acquisition, and potential areas for intervention by addressing key issues pertaining to protective equipment and body armor use.

METHODS

An electronic survey questionnaire was formulated with the close collaboration of US board-certified neurosurgeons from the Mount Sinai Hospital and Cleveland Clinic Departments of Neurosurgery, retired military personnel of the SF, and operational staff of the Green Beret Foundation. The survey was sent to approximately 6000 SF soldiers to understand SCI diagnosis and its associations with various health and military variables.

RESULTS

The response rate was 8.2%. Among the 492 respondents, 94 (19.1%) self-reported an SCI diagnosis. An airborne operation was the most commonly attributed cause (54.8%). Moreover, 87.1% of SF soldiers reported wearing headgear at the time of injury, but only 36.6% reported wearing body armor, even though body armor use has significantly increased in post-9/11 SF soldiers compared with that in their pre-9/11 counterparts. SCI was significantly associated with traumatic brain injury, arthritis, low sperm count, low testosterone, erectile dysfunction, tinnitus, hyperacusis, sleep apnea, posttraumatic stress disorder, major depressive disorder, and generalized anxiety disorder. Only 16.5% of SF soldiers diagnosed with SCI had been rescued via medical evacuation (medevac) for treatment.

CONCLUSIONS

A high number of SF soldiers self-reported an SCI diagnosis. Airborne operations landings were the leading cause of SCI, which coincided with warfare tactics employed during the Persian Gulf War, Operation Iraqi Freedom, and other conflicts. A majority of SCIs occurred while wearing headgear and no body armor, suggesting the need for improvements in protective equipment use and design. The low rate of medevac rescue for these injuries may suggest that medical rescue was not attainable at the time or that certain SCIs were deemed minor at the time of injury.

Resolving the Burden of Low Back Pain in Military Service Members and Veterans (RESOLVE): Protocol for a Multisite Pragmatic Clinical Trial

BACKGROUND

Physical therapy (PT) is frequently used for the management of low back pain (LBP) within the US Departments of Defense (DOD) and Veterans Affairs (VA). However, variations in PT practice patterns and use of ineffective interventions lower the quality and increase the cost of care. Although adherence to the clinical practice guidelines (CPGs) can improve the outcomes and cost-effectiveness of LBP care, PT CPG adherence remains below 50%. The Resolving the Burden of Low Back Pain in Military Service Members and Veterans (RESOLVE) trial will evaluate the effectiveness of an active PT CPG implementation strategy using an education, audit, and feedback model for reducing pain, disability, medication use, and cost of LBP care within the DOD and VA health care systems.

DESIGN

The RESOLVE trial will include 3,300 to 7,260 patients with LBP across three DOD and two VA medical facilities using a stepped-wedge study design. An education, audit, and feedback model will be used to encourage physical therapists to better adhere to the PT CPG recommendations. The Oswestry Disability Index and the Defense and Veterans Pain Rating Scale will be used as primary outcomes. Secondary outcomes will include the LBP-related medication use, medical resource utilization, and biopsychosocial predictors of outcomes. Statistical analyses will be based on the intention-to-treat principle and will use linear mixed models to compare treatment conditions and examine the interactions between treatment and subgrouping status (e.g., limb loss).

SUMMARY

The RESOLVE trial will provide a pragmatic approach to evaluate whether better adherence to PT CPGs can reduce pain, disability, medication use, and LBP care cost within the DOD and VA health care systems.

Worldwide epidemiology of foot and ankle injuries during military training: a systematic review

INTRODUCTION

Musculoskeletal foot and ankle injuries are commonly experienced by soldiers during military training. We performed a systematic review to assess epidemiological patterns of foot and ankle injuries occurring during military training.

METHODS

A review of the literature was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The search, done on 14 February 2019, resulted in 1603 reports on PubMed, 565 on Embase and 3 on the Cochrane Library. After reading the remaining full-text articles, we included 91 studies.

RESULTS

Among a population of 8 092 281 soldiers from 15 countries, 788 469 (9.74%) foot and ankle injuries were recorded. Among the 49 studies that reported on length of training, there were 36 770/295 040 (18.17%) injuries recorded among women and 248 660/1 501 672 (16.56%) injuries recorded among men over a pooled mean (±SD) training period of 4.51±2.34 months. Ankle injuries were roughly 7 times more common than foot injuries, and acute injuries were roughly 24 times more common than non-acute injuries. Our findings indicated that, during a 3-month training period, soldiers have a 3.14% chance of sustaining a foot and ankle injury. The incidence of foot or ankle injury during military parachutist training was 3.1 injuries per thousand jumps.

CONCLUSIONS

Our findings provide an overview of epidemiological patterns of foot and ankle injuries during military training. These data can be used to compare incidence rates of foot and ankle injuries due to acute or non-acute mechanisms during training. Cost-effective methods of preventing acute ankle injuries and non-acute foot injuries are needed to address this problem.

Functional Movement Screen as a Predictor of Occupational Injury Among Denver Firefighters

Background

The Functional Movement Screen (FMS™) is a screening tool used to assess an individual's ability to perform fundamental movements that are necessary to do physically active tasks. The purpose of this study was to assess the ability of FMS to predict occupational injury among Denver Fire Department firefighters.

Method

FMS tests were administered from 2012 to 2016. Claim status was defined as any claim occurrence vs. no claim and an overexertion vs. no claim/other claim within 1 year of the FMS. To assess associations between FMS score and claim status, FMS scores were dichotomized into ≤14 and > 14. Age-adjusted odds ratios were calculated using logistic regression. Sensitivities and specificities of FMS predicting claims at various FMS score cut points, ranging from 10 to 20 were tested.

Results

Of 581 firefighters (mean ± SD, age 38 ± 9.8 y) who completed FMS between February 2015 and March 2018, 188 (32.4%) filed a WC claim in the study time frame. Seventy-two of those (38.3%) were categorized as overexertion claims. There was no association between FMS score and claim status [odds ratio (OR) = 1.27, 95% confidence interval (CI): 0.88 – 1.83] and overexertion claim vs. no claim/other claim (OR = 1.33, 95% CI: 0.81 – 2.21). There was no optimal cutoff for FMS in predicting a WC claim.

Conclusions

Although the FMS has been predictive of injuries in other populations, among this sample of firefighters, it was not predictive of a future WC claim.