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.

Heat Tolerance Testing and the Return to Duty Decision: A Two-Year Case Cohort Analysis

BACKGROUND

Among individuals with prior exertional heat illness (EHI), heat tolerance testing (HTT) may inform risk and return to duty/activity. However, little is known about HTT's predictive validity, particularly for EHI recurrence. Our project sought to demonstrate the predictive validity of HTT in EHI recurrence and HTT's utility as a diagnostic tool in exertional heat stroke (EHS).

METHODS

Participants with prior EHS were recruited for the study by a physician's referral and were classified as heat tolerant or intolerant after completing demographics and an HTT. Participants were further categorized as single/simple (SS) EHI or recurrent/complex (RC) EHI by conducting a retrospective record review of the following two years. We calculated the positive (PPV) and negative predictive values (NPV) of HTT.

RESULTS

The retrospective review of HTT records was used to categorize 44% of Servicemembers as RC, with 77% classified as heat tolerant, 14% as heat intolerant, and 9% as borderline. When borderline cases were classified as heat intolerant, HTT had a high NPV, indicating a high probability that heat-tolerant individuals did not have recurrent EHI. When borderline cases were classified as heat tolerant, NPV and sensitivity decreased while specificity increased.

CONCLUSION

We demonstrated that the HTT had a 100% NPV for future EHI over two years of follow-up for Servicemembers with a history of recurrent heat injury and negative HTT results. An HTT can provide critical data points to inform return to duty decisions and timelines by predicting the risk of EHI recurrence.

Cold Finger: Raynaud Phenomenon Following Snakebite Envenoming by Nikolsky's Viper (Vipera berus nikolskii)

A field biologist was bitten by a female Nikolsky's viper (Vipera berus nikolskii) in Kharkiv Oblast, Ukraine. Two months later, the patient began to experience cold-induced vasospasm of the affected digit diagnosed as acquired Raynaud phenomenon. The patient had more than 30 occurrences during the single winter following the bite, but the signs and symptoms of Raynaud phenomenon disappeared with the end of winter. This report describes the case and puts it into context with the literature on the topic of toxin-induced peripheral vasospastic disorders and their potential importance in snakebite envenoming.

Current Clinical Concepts: Heat Tolerance Testing

Heat tolerance testing (HTT) has been developed to assess readiness for work or exercise in the heat based on thermoregulation during exertion. Although the Israeli Defense Forces protocol has been the most widely used and referenced, other protocols and variables considered in the interpretation of the testing are emerging. Our purpose was to summarize the role of HTT after exertional heat stroke; assess the validity of HTT; and provide a review of best-practice recommendations to guide clinicians, coaches, and researchers in the performance, interpretation, and future direction of HTT. We also offer the strength of evidence for these recommendations using the Strength of Recommendation Taxonomy system.

Exertional heat stroke: An evidence based approach to clinical assessment and management

NEW FINDINGS

What is the topic of this review? The treatment of exertional heat stress, from initial field care through the return-to-activity decision, is reviewed. What advances does it highlight? Clinical assessment during field care using AVPU and vital signs to gauge recovery Approaches to field cooling and end of active cooling Shared clinical decision making for return to activity recommendations ABSTRACT: Exertional heat stroke (EHS) is a potentially fatal condition characterized by central nervous system dysfunction and body temperature often but not always >40°C that occurs in the context of physical work in warm or hot environments. In this paper, we review the continuum of care, from initial recognition and field care to transport and hospital care, and finally return to duty considerations. Morbidity and mortality can be greatly reduced if not eliminated with prompt recognition and aggressive cooling. If medical personnel are not present at point of collapse during or immediately following exercise, EHS should be the presumptive diagnosis until a formal diagnosis can be determined by qualified medical staff. EHS is the rare medical situation where initial treatment (cooling) takes precedence over transport to a medical facility, where advanced medical care may be required for severe EHS casualties. Recovery from EHS and return to activity is usually straightforward and unremarkable provided the casualty is rapidly cooled at time of collapse and adequate time is allowed for body healing. However, evidence-based data to guide return to activity following EHS is limited. Current research suggests that most individuals recover completely within a few weeks though some individuals may suffer prolonged sequalae and additional evaluation may be warranted, including heat tolerance testing. Several aspects of the care of the EHS casualty are based on best practices derived from personal experience and continued research is necessary to optimize evaluation and management. This article is protected by copyright. All rights reserved.

Descriptive Analysis of Casualties Rapidly Returned to the Fight after Injury: Reverse Triage Implications for Large Scale Combat Operations

BACKGROUND

During large scale combat operations, rising numbers of casualties will likely outstrip in-theater US military medical hospitalization assets. This highlights the importance of identifying those casualties who can return to the fight in order to minimize further medical resource depletion. We describe specific characteristics of casualties returned to duty without requiring evacuation from theater during recent major combat operations.

MATERIALS AND METHODS

We conducted a secondary analysis of previously published data from the Department of Defense Trauma Registry during 01 January 2007 through 17 March 2020. We included all adult US military casualties. We categorized casualties according to documented disposition, namely, return to duty within 72 hours without evacuation from theater, return to duty greater than 72 hours without evacuation from theater, and all other casualties.

RESULTS

Of 10,182 adult US military casualties, 3,856 (37.9%) returned to duty within 72 hours without evacuation from theater and 220 (2.2%) returned to duty in greater than 72 hours without evacuation from theater. The cohort that rapidly returned to duty had a lower median injury severity score (2) than casualties returning to duty in greater than 72 hours (4) and those evacuated from theater (11). Notably higher proportions of casualties evacuated from theater sustained injuries to the face, thorax, abdomen, and extremities. Modes of transportation were similar across all three groups, though casualties undergoing evacuation from theater were more likely to undergo air transportation during the spectrum of their medical care.

CONCLUSIONS

Most combat casualties returning to duty without evacuation from theater did so within 72 hours of hospitalization. Casualties not requiring evacuation from theater were less likely to sustain injuries to the face, thorax, abdomen, and extremities.

Primary Medial Patellofemoral Ligament Reconstruction in Military Servicemembers: Can We Reliably Restore Preinjury Function and Stability?

Background:

Medial patellofemoral ligament (MPFL) reconstruction for patellar instability is a commonly performed procedure with a reported high rate of return to preinjury activity. However, no previous study has assessed the functional outcomes of military servicemembers undergoing MPFL reconstruction.

Hypothesis:

Primary MPFL reconstruction confers patellar stability, but with limited return to preinjury function and ability to maintain unrestricted military active duty status.

Study Design:

Case series; Level of evidence, 4.

Methods:

Using the Management Analysis and Reporting Tool database, we conducted a retrospective review of active duty servicemembers throughout the US Department of Defense Health System who underwent primary MPFL reconstruction between 2012 and 2015. Demographic variables were recorded as well as ability to return to impact activities—defined as running, jumping, rucking with a load >40 pounds (18 kg), and returning to airborne operations—and to remain on active duty status. The rates of recurrent instability and the need for subsequent surgeries were identified and assessed for statistical significance using uni- and multivariate analyses. Patients were evaluated for a minimum of 2 years postoperatively.

Results:

Of the 213 patients who underwent primary MPFL reconstruction, including 34 with concomitant tibial tubercle osteotomy, 19 (8.9%) patients developed recurrent instability. The presence of bilateral patellar instability was associated with higher recurrence rate. Patients with bilateral instability comprised 47.3% of those with recurrence but only 24.9% of patients without recurrence (P = .019). Impact activity restrictions were present in 57.6% of patients (n = 121), with 86 patients (52.1%) undergoing medical separation from the military. Patients who were prescribed activity restriction before surgery were significantly more likely to have postoperative activity restrictions (64.5%; P = .019), and junior enlisted servicemembers were more likely to be medically separated from service postoperatively than higher ranking senior enlisted members or officers.

Conclusion:

Only 42.4% of US military servicemembers undergoing primary MPFL reconstruction were able to return to unrestricted impact activity after surgery. Bilateral instability negatively affected return to impact activities. Military servicemembers, particularly junior enlisted members, should be counseled on this poor prognosis for a full return to unrestricted activity postoperatively.

RETURNING A SPECIAL OPERATIONS CANDIDATE TO DUTY FOLLOWING AN AIRBORNE OPERATION INJURY: A CASE REPORT

BACKGROUND

Musculoskeletal injuries are recognized as the leading health problem and primary source of injury, disability, and financial burden across the military.^1-5 Special Operations Forces are at an increased risk of musculoskeletal injury due to increased physical demands, precipitous deployments, and continual training and deployment cycles.^6,4 Multiple injury screening tools exist, yet decisions to return to duty are frequently deferred to individual institutional protocol or provider clinical decision making, with no accepted gold standard.^2,3,4,5.

PURPOSE

The purpose of this case report is to describe the application of a system to return a Special Operations Forces candidate to duty following an ankle injury sustained during a military static line airborne operation while in the Special Forces Qualification Course.

CASE DESCRIPTION

The subject was a 34-year-old male with surgical fixation of a left distal fibular fracture with syndesmotic tear after landing from a static line airborne jump during the Special Forces Qualification Course. This case report provides a system to determine return to duty following an ankle fracture and provides a guide to returning a subject to participation, duty, and tactical performance training.

OUTCOMES

Outcome measures recorded were vast, as the use of multiple measures are more indicative of overall function than any single measure. Impairment based measures included Global Rating of Change Scale (GROC), Numeric Pain Rating Scale (NPRS), lateral step down and Closed Chain Dorsiflexion (CCDF). Functional outcome measures included: the Functional Movement Screen™ (FMS™), Lower Quarter Y-Balance (LQYB), three hop tests for distance, and physical performance metrics.

DISCUSSION

The most substantial challenge to this process was the lack of standardized and validated military return to duty testing and guidelines in the literature. Ideally, pre-injury assessment would provide a baseline; however, compared to peers, the subject was well within acceptable ranges for all physical performance metrics at final Return to Duty testing. The subject was returned to duty 10 months after initial injury being physically comparable to his cohorts and being able to complete all military requirements.

LEVELS OF EVIDENCE

5.

When Should a Heat-Tolerance Test Be Scheduled After Clinical Recovery From an Exertional Heat Illness?

OBJECTIVE

Researchers have produced a hypothesis of transient heat intolerance (HI) after exertional heat stroke (EHS). Based on this hypothesis, heat-tolerance testing (HTT) has been postponed until weeks 6 to 8 after EHS and other types of exertional heat illness (EHI). We compared the HTT results of participants after either EHS or other EHI who were tested earlier (≤6-week group) versus those who were tested later (>6-week group) to verify the hypothesis.

DESIGN

Cohort study.

SETTING

Data obtained from records of military athletes who experienced EHS or EHI.

PATIENTS OR OTHER PARTICIPANTS

All participants who underwent HTT after EHI or EHS experienced between 2014 and 2018 and for whom complete data regarding the severity of the event (rectal temperature, neurologic symptoms, and laboratory results) and HTT results were available were included. Participants with suspected EHS and those with other EHIs were evaluated separately.

MAIN OUTCOME MEASURE(S)

The percentages of participants with HI and mean probability of heat tolerance were compared between those tested within 6 weeks of the event and those tested later.

RESULTS

A total of 186 participants were included in this study (EHS: 12 in the <6-week group, 9 in the >6-week group; EHI: 94 in the <6-week group, 71 in the >6-week group). In the EHS group, the percentages with HI (33% versus 44%, P = .67) and mean probability of heat tolerance (0.82 versus 0.82, P = .98) did not differ. In the EHI group, participants who were tested after 6 weeks had a greater chance of being diagnosed with HI (38% versus 21.3%, P < .02).

CONCLUSIONS

The HTT results were similar between participants with EHS who were tested early (<6 weeks) and those tested late (>6 weeks). Further investigation of heat-tolerance changes in larger cohorts of patients after EHS is required to verify the theory of transient HI.

Use of the heat tolerance test to assess recovery from exertional heat stroke

Exercise or work in hot environments increases susceptibility to exertional heat illnesses such as exertional heat stroke (EHS). EHS occurs when body heat gain exceeds body heat dissipation, resulting in rapid body heat storage and potentially life-threatening consequences. EHS poses a dangerous threat for athletes, agriculture workers, and military personnel, as they are often exposed to hot environmental conditions that restrict body heat loss or contribute to body heat gain. Currently, there is limited guidance on return to activity (RTA) after an episode of EHS. While examining biomarkers in the blood is thought to be beneficial for determining RTA, they are not sensitive or specific enough to be a final determining factor as organ damage may persist despite blood biomarkers returning to baseline levels. As such, additional assessment tests to more accurately determine RTA are desired. One method used for determining RTA is the heat tolerance test (HTT, 120 minutes treadmill walking; 40°C, 40% relative humidity). Unfortunately, the HTT provides even less information about EHS recovery since it offers no test sensitivity or specificity even after years of implementation. We provide an overview of the HTT and the controversy of this test with respect to assessment criteria, applicability to tasks involving high metabolic workloads, and the lack of follow-up analyses to determine its accuracy for determining recovery in order to diminish the likelihood of a second EHS occurrence.

Probability of Heat Intolerance: Standardized Interpretation of Heat-Tolerance Testing Results Versus Specialist Judgment

CONTEXT

  The heat-tolerance test (HTT) is a screening tool for secondary prevention of exertional heat illness by the Israel Defense Forces. To discern participant tolerance, recruits are exposed to intermediate environmental and exercise stresses, and their physiological responses, core temperature, and heart rate are monitored. When their physiological measures rise at a higher rate or exceed the upper levels of absolute values compared with other participants, heat intolerance (HI) is diagnosed.

OBJECTIVE

  To develop a mathematical model to interpret HTT results and provide a quantitative estimate of the probability of heat tolerance (PHT).

DESIGN

  Cross-sectional study.

SETTING

  Warrior Health Research Institute.

PATIENTS OR OTHER PARTICIPANTS

  The HTT results of 175 random individuals tested after an episode of exertional heat illness were classified qualitatively and then divided into training (n = 112) and testing (n = 63) datasets. All individuals were male soldiers (age range = 18-22 years) who had sustained an episode of definitive or suspected exertional heat stroke.

MAIN OUTCOME MEASURE(S)

  Based on the decision algorithm used by the Israel Defense Forces for manual interpretation of the HTT, we designed a logistic regression model to predict the heat-tolerance state. The model used a time series of physiological measures (core temperature and heart rate) of individuals to predict the manually assigned diagnosis of HT or HI. It was initially fitted and then tested on 2 separate, random datasets. The model produced a single value, the PHT, and its predictive ability was demonstrated by prediction-density plots, receiver operating characteristic curve, contingency tables, and conventional screening test evaluation measures.

RESULTS

  According to prediction-density plots of the testing set, all HT patients had a PHT of 0.7 to 1. The receiver operating characteristic curve plot showed that PHT was an excellent predictor of the manual HT interpretations (area under the curve = 0.973). Using a cutoff probability of 0.5 for the diagnosis of HI, we found that PHT had sensitivity, specificity, and accuracy of 100%, 90%, and 92.06%, respectively.

CONCLUSIONS

  The PHT has the potential to be substituted for manual interpretation of the HTT and to serve in a variety of clinical and research applications.

Common mental disorders among US army aviation personnel: Prevalence and return to duty

OBJECTIVES

Assess the prevalence of US Army aviation personnel with common mental disorders, the percentage that return to duty following mental health treatment, and predictors of return to duty.

METHODS

Examined the prevalence over a 5-year period. The percentage of personnel who were granted a waiver to return to flying duty following treatment was also determined.

RESULTS

The results revealed a 5-year prevalence of 0.036 (95% CI = 0.034-0.038) for personnel experiencing one or more of the mental disorders (N = 1,155). Prevalence was highest for adjustment disorders and for nonpilot participants. Overall, personnel were granted a waiver 55.3% of the time and suspended or disqualified 44.7% of the time. Waivers were more likely to be granted for an adjustment disorder and for pilots.

CONCLUSIONS

Discussion focuses on the importance of aviation personnel receiving mental health treatment when problems are not severe to maximize the likelihood of returning to duty.

A Retrospective Study of Predictors of Return to Duty versus Medical Retirement in an Active Duty Military Population with Blast-Related Mild Traumatic Brain Injury

Traumatic Brain Injury (TBI) has been described as the "signature injury" of the Global War on Terror. Explosive blast TBI has become a leading cause of injury as a result of the widespread use of improvised explosive devices in Iraq and Afghanistan. We present a retrospective cross-sectional study of patients with blast-related mild TBI (mTBI, N = 303) seen at the Intrepid Spirit Concussion Recovery Center at Naval Medical Center Camp Lejeune. The objective was to predict outcomes of return to duty (RTD) vs. medical retirement via medical evaluation board (MEB), based on brain imaging, neuropsychological data, and history of mTBI. The motivation is to inform prognosis and target resources to improve outcomes for service members who are less likely to RTD through the standard treatment program. The RTD was defined operationally as individuals who completed treatment and were not recommended for medical retirement or separation for TBI or related sequelae. Higher scores on the Repeatable Battery for Neuropsychological Status (RBANS) test were associated positively with RTD (p = 0.001). A history of three or more lifetime concussions was associated negatively with RTD, when compared with one concussion (p = 0.04). Elevated apparent diffusion coefficient (ADC) in the anterior corona radiata was associated negatively with RTD (p = 0.04). A logistic regression model was used to classify individuals with RBANS and imaging data (n = 81) as RTD or MEB according to RBANS, ADC, and a history of multiple (≥3) concussions. The RBANS (p = 0.003) and multiple concussions (p = 0.03) were significant terms in the logistic model, but ADC was not (p = 0.27). The area under the receiver operating characteristic curve was 0.77 (95% confidence interval 0.66-0.86). These results suggest cognitive testing and TBI history might be used to identify service members who are more likely to be retired medically from active duty.

Hip Arthroscopy for Femoroacetabular Impingement in a Military Population

BACKGROUND

Femoroacetabular impingement (FAI) can lead to hip pain and early joint degeneration. There have been few reports to date on the outcomes of hip arthroscopy for the treatment of FAI in the military population. Purpose/Hypothesis: The purpose of this study was to compare patient demographics with postoperative outcomes after hip arthroscopy for symptomatic FAI and to identify preoperative risk factors for poor outcomes. The hypothesis was that certain preoperative patient characteristics will be predictive of poorer outcomes and that lower outcomes scores will be associated with a higher likelihood of medical separation from the military.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Retrospective chart review of active-duty and dependent patients older than 18 years who underwent hip arthroscopy for symptomatic FAI from 2009 to 2014 at a single institution.

RESULTS

A total of 469 (309 males and 160 females) surgeries were performed on 456 active-duty personnel and 13 dependent civilians, with a mean 2.5-year follow-up. Overall, 39% (n = 179) were able to return to duty (RTD), 18% (n = 82) were medically cleared to return to normal daily activities but did not remain on active duty, and 43% (n = 195) required referral to the Disability Evaluation System (DES). Increasing rank and male sex were positive predictors and Axis 1 psychiatric diagnosis, revision surgery, concomitant psoas tenotomy, multiple medical comorbidities, and complaints of generalized pelvic pain were negative predictors for returning to duty. US Marine Infantry and Special Forces showed improved RTD rates (50%-86%) compared with administrative, more sedentary, occupations (22%). On average, Single Alpha Numeric Evaluation (SANE) and visual analog scale (VAS) scores improved after surgery, with SANE scores improving 37 ± 28 points and VAS scores improving 2.6 ± 2.5 points. The mean postoperative SANE and VAS scores differed significantly between the RTD group and those not returning to duty; 87 and 1.2 points compared with 69 and 3.6 points, respectively ( P < .0001).

CONCLUSION

Hip arthroscopy for the treatment of symptomatic FAI effectively improves pain symptoms and self-reported overall function but shows a much lower than expected return to full, unrestricted active duty in the general active-duty military population. Underlying psychiatric diagnoses, female sex, and more sedentary occupations are associated with lower RTD rates. Furthermore, lower postoperative SANE and VAS scores are associated with lower RTD rates. Only the more active and elite components of the military study population showed RTD rates consistent with previously reported outcomes of return to competitive sports after hip arthroscopy for FAI.

Kinematic analysis of males with transtibial amputation carrying military loads

The biomechanical responses to load carriage, a common task for dismounted troops, have been well studied in nondisabled individuals. However, with recent shifts in the rehabilitation and retention process of injured servicemembers, there remains a substantial need for understanding these responses in persons with lower-limb amputations. Temporal-spatial and kinematic gait parameters were analyzed among 10 male servicemembers with unilateral transtibial amputation (TTA) and 10 uninjured male controls. Participants completed six treadmill walking trials in all combinations of two speeds (1.34 and 1.52 m/s) and three loads (none, 21.8, and 32.7 kg). Persons with TTA exhibited biomechanical compensations to carried loads that are comparable to those observed in uninjured individuals. However, several distinct gait changes appear to be unique to those with TTA, notably, increased dorsiflexion (deformation) of the prosthetic foot/ankle, less stance knee flexion on the prosthetic limb, and altered trunk forward lean/excursion. Such evidence supports the need for future work to assess the risk for overuse injuries with carried loads in this population in addition to guiding the development of adaptive prosthetic feet/components to meet the needs of redeployed servicemembers or veterans/civilians in physically demanding occupations.