Musculoskeletal injuries in military personnel-Descriptive epidemiology, risk factor identification, and prevention

Patterning of Musculoskeletal Injuries in the U.S. Army: A Sociocentric Social Network Analysis

INTRODUCTION

Musculoskeletal injuries (MSKIs) are the most prevalent and costly threat to U.S. soldier health and medical readiness. Although sociodemographic and physical factors contributing to MSKIs have been well studied, the role of social relationships-particularly social disconnection-remains underexplored, despite mounting evidence of its negative impact on health outcomes.

MATERIALS AND METHODS

Cross-sectional sociocentric social network analysis was applied to 2 Army combat arms units (N = 776; Cohort 1 [C1] N = 394, Cohort 2 [C2] N = 382). Social interaction networks were measured by asking soldiers to identify others within their unit with whom they socialized outside of duty hours. Descriptive analyses followed by multiple logistic regression with quadratic assignment procedure assessed dyadic similarity in injury status accounting for network dependencies, sociodemographic variables, and known risk factors for MSKIs.

RESULTS

Participants, representative of combat arms units, were predominately young, male, White, and single and had a mean time in service of 5 to 6 years (C1: 5.6 ± 4.4 years, C2: 5.9 ± 4.7 years). Over 25% reported duty-limiting profiles for MSKIs (C1: 26.1%, C2: 27.7%). Injured soldiers were significantly more likely to identify other injured soldiers as those with whom they socialized outside of duty hours (C1 OR= 1.255, P = .040; C2 OR = 1.336, P = .008). High modularity scores (C1: 0.767, C2: 0.788) indicated distinct, cohesive subgroups. Injured soldiers also endorsed having 0.76 to 1.5 fewer social ties compared to uninjured soldiers (P = .025 [C1], P = .003 [C2]).

CONCLUSIONS

Injured soldiers were distributed non-randomly within military units, forming distinct subgroups and reporting significantly fewer social ties compared to uninjured soldiers. Future studies should explore whether social disconnection increases susceptibility to MSKIs through social selection or influence, whether MSKIs reduce social connection and integration, or if both dynamics interact.

Quantifying the Functional Impact of Chronic Patellofemoral Pain and Its Relationship to Perceived Duty-related Medical Readiness Among Active Duty Service Members

INTRODUCTION

Chronic patellofemoral pain (PFP) is a heterogeneous pain condition that may significantly burden active duty service members, whose rigorous physical training demands include activities such as running and heavy load carriage. While chronic PFP is often defined by its pathoanatomical characteristics, evidence from other pain conditions (e.g., chronic low back pain) suggests classifying pain by its functional impact on work, social, and self-care activities may better inform personalized treatment approaches. As this approach has not been previously undertaken in chronic PFP or younger populations with chronic pain, this study aimed to characterize the global impact of PFP on day-to-day function and evaluate its relationship with perceived duty-related medical readiness among young, active service members.

MATERIALS AND METHODS

Institutional Review Board approval was obtained at Naval Medical Center San Diego. Electronic health records were retrospectively reviewed among 295 service members referred to physical therapy for "knee pain" from April 2021 to April 2022. For service members with chronic PFP (i.e., anterior knee pain present for at least 3 months and on at least half the days in the past 6 months), demographic, pain-related, and standardized outcome measure data were extracted from physical therapy intake documentation. Knee function was quantified using the validated Anterior Knee Pain Scale, scored from 0 to 100 (100 = highest function). Patient-reported Outcomes Measurement Information System Computer Adaptive Tests for physical function and pain interference were collected and subcategorized from 0 (within normal limits) to 3 (severe limitation) based on t-score cut-points, then summed to create a Pain Impact Score (0 = no impact to 6 = severe impact). Finally, perceived duty-related medical readiness was averaged across 2 questions assessing confidence in performing deployment and military duties with well-managed pain, each scored from 0 to 100 (100 = highest readiness). Relationships between Pain Impact Scores and perceived duty-related medical readiness were evaluated using linear regression after controlling for age, sex, symptom chronicity, and knee function.

RESULTS

Overall, 56 active duty service members, of whom 66% were males, met the criteria for chronic PFP and had outcome measures documented in their electronic health records. Most service members were classified as having mildly impaired physical function (46%) and moderately impaired pain interference (41%), while only 12 (21%) fell within normal limits for both physical function and pain interference domains. Median (25th-75th percentile) Pain Impact Scores were 2 (1-3). The overall regression model was statistically significant (R2 = 0.540, F(5,50) = 11.76, P < .001). Beyond covariates, Pain Impact Scores explained an additional 21.0% of the variance in perceived duty-related medical readiness (P < .001).

CONCLUSIONS

Service members with chronic PFP frequently report impaired physical function and pain interference, opposing assumptions that PFP is a mild, self-limiting condition. As each 1-point increase in Pain Impact is associated with a 10-point decrease in perceived duty-related medical readiness, functional pain impact should be evaluated alongside other condition-specific factors (e.g., knee function) to identify rehabilitation targets among service members with chronic PFP. Future work should explore whether similar associations are found between functional pain impact and other objective readiness measures (e.g., physical fitness tests).

Science behind policy: implementing a modern circumference-based body fat equation with a physical fitness threshold is associated with lower musculoskeletal injury risk

BACKGROUND

Body composition influences physical fitness (PF) and risk of musculoskeletal injury (MSKI). Assessing the relationship between body fat (BF), PF and MSKI risk in a large diverse military population may provide evidence basis informing health-care policies, practices, and programs for military and civilian populations.

OBJECTIVE

Evaluate the validity of expedient methods to estimate BF (e.g., circumference-based equation (CBE) and bioelectrical impedance analysis (BIA)) and investigate relationships between BF and PF with MSKI risk in a large diverse population.

METHODS

Participants were 1904 active-duty Soldiers (643 F) representing Army demographics sex, race/ethnicity (R/E), and age. PF, defined as the most recent Army Combat Fitness Test (ACFT) score and incidence of MSKI, were obtained from Army records. BF was determined by dual-energy x-ray absorptiometry (%BFDXA), bioelectrical impedance analysis (%BFBIA), and CBE using 3-site (Hodgdon, %BFHE) and 1-site (Taylor-McClung, %BFTM) equations. Results were stratified by race and sex, to evaluate differences in accuracy of estimated %BF (weighted root mean squared error from %BFDXA). Associations of BF and PF with MSKI risk were evaluated with logistic regression.

RESULTS

CBE and BIA underestimated %BF compared to %BFDXA. %BFBIA differed from %BFDXA overall and by sex. %BFTM underestimation was uniform across both sex and R/E compared to %BFDXA. Mean differences from %BFDXA by sex (M;F) were lower when measured by %BFTM (4.38; 4.59) compared to %BFHE (5.88; 4.39). Individuals had a greater likelihood of MSKI if they failed BF standards (odds ratio 1.32). Scoring ≥ 540 total on ACFT exhibited a 31% (95% CI: 0.52, 0.92) lower MSKI risk during the following 12 months than those with a lower score.

CONCLUSIONS

A single-site BF equation (%BFTM) maintained similar accuracy across the Soldier population by sex, age, and R/E. Implementing a PF score threshold in lieu of passing Army BF standards was associated with lower MSKI risk.

Relationship between bilateral symmetry of foot posture and lower limb musculoskeletal injuries among workers engaged in physically demanding occupations: A cross-sectional investigation

Even though the link between foot posture and lower-extremity injuries remains controversial, there has been little research focus on bilateral foot symmetry. This study evaluated the correlation between bilateral symmetry in foot posture and lower extremity musculoskeletal injuries among workers in physically intensive occupations. A total of 248 participants with physically demanding roles were enrolled. Historical data on lower-limb musculoskeletal injuries were obtained through a review of medical records, supplemented by results from on-site consultations. The foot arch index (AI) was quantitatively measured using a 3D laser foot scanner, and foot posture was evaluated using the foot posture index-6 (FPI-6). The participants were categorized into subgroups based on bilateral symmetry assessments of their feet. Logistic regression analyses were performed for statistical comparisons after adjusting for potential confounding factors. The results indicate that abnormalities in foot posture and arch, assessed using the FPI-6 and AI, were identified in 42.3 ​% and 47.2 ​% of participants, respectively, with 20.9 ​% and 16.5 ​% demonstrating bilateral asymmetry in these parameters. When comparing bilateral and unilateral foot protonation with bilaterally normal feet, the risk adjustments revealed differences of 2.274 (95 ​% CI: 1.094-4.729, P ​= ​0.028) and 2.751 (95 ​% CI: 1.222-6.191, P ​= ​0.015), respectively. Furthermore, the risk adjustment for age, BMI, smoking status, physical training years, training time, training frequency, warm-up before training, relaxation after training, MIS prevention, and treatment learning for unilateral flatfoot relative to bilateral normal feet was 3.197 (95 ​% CI:1.235-8.279, P ​= ​0.017). This study demonstrates that workers in physically demanding occupations who exhibit unilateral foot protonation or unilateral flatfoot are at an increased risk of lower-extremity musculoskeletal injuries.

Current Use and Effects of Osteopathic Manipulative Treatment (OMT) in the Military: A Scoping Review

Osteopathic manipulative treatment (OMT) is a hands-on therapy approach used by osteopathic physicians that aims to alleviate viscero-somatic changes by considering the interconnectedness of the body, mind, and spirit. One of the most common uses for OMT is the treatment of musculoskeletal (MSK) complaints, which are a significant cause of pain and disability across various populations, including the US Military, where personnel often face unique and physically demanding working conditions. In 2019, MSK injuries alone accounted for nearly half of the limited duty days in the US Army, with low back pain being the leading cause of medical encounters over the past 10 years among active-duty personnel. Previous studies have shown that OMT can improve functional status, reduce pain, and have minimal adverse effects when treating low back pain. It has also been found to be twice as effective as placebo treatments and comparable to nonsteroidal anti-inflammatory drugs in terms of pain relief. Given the high incidence rates of MSK issues during active duty in the military, OMT may be a viable treatment or adjunctive therapy option for this population. The purpose of this scoping review is to evaluate the current research on OMT among US military members and veterans, determining any potential positive or negative effects that may be attributed to this therapy. A comprehensive search was conducted across six databases from inception to November 2023, yielding 497 articles, which were screened according to inclusion and exclusion criteria. Nine studies were ultimately included and evaluated based on the target treatment area. The most commonly employed forms of OMT included myofascial release, soft tissue manipulation, and counterstrain techniques. The primary outcomes after OMT were reduced pain and improved range of motion or functionality. Other positive findings included a decrease in opioid usage, reduced nausea, lower healthcare costs, and lower incidence of alcohol and substance use disorders within the military populations studied. This is the first review of its kind to evaluate OMT within military populations, demonstrating its effectiveness in reducing pain, increasing functionality, and lowering complications associated with military duties. Further research into the utilization of OMT within the military should be pursued, considering it as a potential first-line or adjunctive therapy for service members and veterans across various settings and dysfunctions to continue evaluating its long-term effectiveness.

Soldier performance management: insights from boots on ground research and recommendations for practitioners

Theoretically, the serial measurement of biomarkers to monitor physiological responses to military training could be used to mitigate musculoskeletal injury risk and better understand the recovery status of personnel. To date, the cost and scalability of these initiatives have impeded their uptake by defence organisations. However, advances in technology are increasing the accessibility of a range of health and performance biomarkers. This paper presents a synthesises of findings from the literature and discussions with informed stakeholders to provide contextually relevant advice for future efforts to monitor military personnel, together with key considerations to ensure actionable outcomes from the data captured. The aim of this review is, therefore, twofold; first, to demonstrate how wearable devices and biomarkers have been used in defence research to assess the context-specific, occupational demands placed on personnel; and second, to discuss their potential to monitor military workloads, optimise training programming and understand soldier adaptation to multi-stressor environments.

Tibial Skeletal Adaptations in Male and Female Marine Corps Officer Candidates Undergoing 10 Weeks of Military Training

Military training improves tibial density, structure, and estimated strength; however, men and women may adapt differently. Most work performed in military populations has assessed changes in bone health during initial entry programs, a timeframe at the beginning of a service member's career when bones may be more adaptable to a novel mechanical stimulus. The purpose of this investigation was to examine changes in tibial volumetric bone mineral density (vBMD), structure, and estimated strength, and biomarkers of bone metabolism (P1NP, osteocalcin, TRAP5b, sclerostin) between male and female candidates measured at the start and end of United States Marine Corps Officer Candidates School (OCS), a 10-week military training program attended by older service members (~ 25 y/o) who may have previous military experience. Peripheral quantitative computed tomography (pQCT) of the tibia (n = 375) and blood draws (n = 385) were performed. Generalized linear mixed effects modeling compared changes between sexes over time. Increases in total and trabecular vBMD were observed at the 4% site in the total sample, but total and cortical vBMD decreased in female candidates at the 66% site. Periosteal circumference at the 38% and 66% sites increased in the total sample. Estimated strength increased similarly in male and female candidates at the 4% and 38% sites but only increased in male candidates at the 66% site. Concentrations of P1NP and osteocalcin increased similarly in both sexes, although sclerostin and TRAP5b decreased only in male candidates. Measures of tibial vBMD, width, and estimated strength increased following OCS consistent with adaptive bone formation.

The Relationship Between Self-Efficacy, Aerobic Fitness, and Traditional Risk Factors for Musculoskeletal Injuries in Military Training: A Prospective Cohort Study

Background

The United States military strives to prepare soldiers physically and mentally for war while preventing injury and attrition. Previous research has focused on physical injury risk factors but has not prospectively examined psychological risk factors.

Purpose

This study's purpose was to investigate whether self-efficacy is a risk factor for musculoskeletal injury in an initial military training environment and compare it to other known risk factors.

Study Design

Prospective, Longitudinal Cohort Study.

Materials and Methods

Shortly after starting cadet basic training, new cadets rated self-efficacy by an 11-point questionnaire. Other risk factor data including injury history, sex, height, weight, body mass index, age, aerobic fitness, upper body muscular endurance, core muscular endurance and previous military experience were collected by self-report questionnaire and military fitness testing. The primary dependent variable was musculoskeletal injury that originated during the seven-week course. Independent variables were compared between participants who were and were not injured using Chi-squared test, t-tests, Cox regression analysis and time to injury was evaluated using Kaplan-Meyer survival analyses.

Results

Seven hundred eighty-one (65.1%) new cadets were eligible and consented to participate. Injured cadets had significantly lower self-efficacy scores (p=0.003 and p=<0.001), shorter height (p=<0.001), lower weight (p=0.036), lower push-up and plank performance (p=<0.001), slower two-mile run performance (p=<0.001), and females sustained a proportionally higher number of injuries than males (p=<0.001). Cadets with low self-efficacy, shorter height, lower hand release push-up performance, lower plank performance and slower two-mile run performance were at greater risk for musculoskeletal injury. Cadets with less self-efficacy were also less likely to continue uninjured throughout cadet basic training according to a Kaplan-Meier survival analysis (log rank test<0.002). Multivariable Cox regression revealed that only aerobic fitness predicted musculoskeletal injury (HR=1.005 [1.003-1.006], p=<0.001).

Conclusions

Participants with less self-efficacy sustained injuries earlier and more often than those with greater self-efficacy. However, aerobic fitness alone predicted future injury after controlling for all risk factors. Resolved prior injury was not a risk factor for future injury.

Level of Evidence 2b

Individual cohort study.

Home Use Therapies for Pain, Disability, and Quality of Life in Military Service Members with a Musculoskeletal Injury: An Updated Systematic Review Meta-Analysis

INTRODUCTION

Musculoskeletal (MSK) injury can negatively affect service members by compromising job performance and readiness. These injuries can impact the service member's physical health, functional abilities, and quality of life (QoL). Rehabilitation therapies for MSK injuries can reduce these impacts. One approach is home use rehabilitative therapy, usable during deployment and at home stations. The purpose of this updated systematic review with meta-analysis was to broaden our scope of pain/symptoms, disability, and QoL as outcome measures for nonpharmaceutical MSK therapies in a military population versus controls.

MATERIALS AND METHODS

An updated systematic literature search was conducted from inception to September 2022 using electronic databases. From 2790 retrievals, 22 reports were identified from 21 randomized or nonrandomized control trials. Interventions included exercise, electrotherapy, bracing, and other devices compared to a standard control treatment. Outcomes for MSK pain/symptoms, disability, and QoL were summarized as (1) standardized change from baseline for both intervention and control by time and (2) standardized mean differences (SMDs) in the time change between the intervention and control.

RESULTS

Relative to baseline, pain improved during treatment and follow-up (P < .0001) with differences between intervention and control groups (P < .0001) but no significant interactions between group and time (P = .11). Overall, interventions showed modest (0.33 SMD, 95% CI, 0.11 to 0.54) improvement relative to controls across body regions and time. On average, disability exhibited an SMD of 0.12 (95% CI, -0.20 to 0.44) across all measures with substantial heterogeneity (I2 = 0.93). Time (P = .02) but not intervention (P = .87) was a significant moderator with no clear pattern of change over time and no time by group interaction (P = .84). Quality of life had an overall modest effect with an SMD of 0.10 (95% CI, -0.04 to 0.24) with no evidence supporting a difference between the intervention and control groups (P = .10) and no significant interaction between time and group (P = .41). The QoL measures were primarily derived using the Short Form Health Survey (SF12/36), which provide a mental and physical component summary score. For the mental component, there was either no change or a small decline during the study (P(time) = .80), with a difference between the intervention and control (P = .04) but no interaction between groups over time (P = .40). For the physical component scale, there was improvement during the study (P = .01), with the intervention showing better improvement than the control (P = .005), with no interaction between the time and treatment/control group (P = .80). The report considers responses by region and individual treatments.

CONCLUSIONS

This analysis demonstrated modest improvement in pain and physical well-being with therapy, with low certainty across diverse military cohorts. The impact on overall health-related disability and QoL was limited, with little change in mental well-being. The substantial heterogeneity and low certainty across diverse military cohorts limit generalizability, suggesting that further research in homogeneous environments is important for guiding clinical decisions. The study's findings suggest that nonpharmacological home use interventions may offer modest improvements in pain relief, particularly early in treatment, and in strength and function, according to our previous report. These interventions could complement standard care, providing options that may benefit service members during deployment and at home.

Inflammatory and Oxidant Responses to Arduous Military Training: Associations with Stress, Sleep, and Performance

BACKGROUND

Arduous military training frequently consists of prolonged physical activity, sleep disturbance, and stress that increases musculoskeletal injury risk and performance decrements. Inflammatory and oxidative stress responses have been reported in response to arduous training, but with inconsistencies across markers and with underrepresentation of women. The purpose of the current report was to measure circulating inflammation and oxidative stress responses to military training and to correlate biomarkers with subjective measures of stress and sleep quality as well as military fitness test performance.

METHODS

Candidates undergoing the 10-wk Marine Corps Officer Candidate School (OCS; 101 men, 62 women) were monitored, with demographic and questionnaire data collected, and blood drawn before and after OCS. Blood was analyzed for six markers of inflammation and three markers of oxidative stress. Associations between biomarkers and questionnaire and fitness test performance were tested.

RESULTS

All measured inflammatory markers as well as plasma antioxidant capacity were elevated following OCS. The inflammatory increase was higher in women for several markers. Sleep disturbance and stress perception were associated with interleukin (IL)-6, IL-10, and C-reactive protein concentrations, suggesting that low sleep disturbance and stress perception were associated with low inflammatory load. In addition, those with the highest inflammation at each time point performed worse on fitness tests than those with low inflammation.

CONCLUSIONS

Following arduous military training, the circulating environment in a significant portion of officer candidates resembled chronic low-grade inflammation. This circulating inflammatory environment appeared worse with poor sleep, high stress perception, and poor fitness test performance, with utility observed for C-reactive protein, IL-6, and IL-10 as biomarkers of these responses. Because inflammation may contribute to musculoskeletal injury and performance decrements, minimizing chronic inflammation during military training should be explored.

Burden of Musculoskeletal Injuries in U.S. Active Duty Service Members: A 12-Year Study Spanning Fiscal Years 2010-2021

BACKGROUND

Musculoskeletal injuries (MSKIs) represent the most substantial and enduring threat to U.S. military readiness. Previous studies have focused on narrow surveillance periods, single branches of service, and used variable approaches for MSKI identification and classification. Therefore, the goals of this retrospective population study were to report the incidence, prevalence, and types of MSKIs sustained by active duty service members (ADSMs) across four Services in direct care (DC) and private sector care (PC) settings over fiscal years (FYs) 2010-2021, and to quantify and describe associated health care utilization and PC costs over the same period.

METHODS

This study included ADSMs from the Air Force, Army, Marine Corps, and Navy. Prevalence and incidence rates for Head/Neck, Upper Extremity (UE), Spine (upper back, middle back, lower back, pelvic), and Lower Extremity (LE) MSKIs in ADSMs, associated health care utilization, and PC costs were derived by querying electronic health records from DC, PC claims, and theater medical data from the Military Health System Data Repository. Patient episodes of care and associated PC costs related to MSKIs in DC and PC settings were classified into mutually exclusive outpatient encounter categories and acute inpatient stays, body regions, and Services.

RESULTS

Over FY10-21, the most prevalent MSKIs were LE (24-29%) followed by Spine (17-20%), UE (14-16%), and Head/Neck (6-8%). Across FY10-21, soldiers were more likely to sustain LE MSKI than Airmen (risk ratio 1.12-1.30) and Marines demonstrated an increasing risk of LE MSKI prevalence and incidence (relative to Airmen) over the study period. The rise in prevalence of LE, Spine, UE, and Head/Neck MSKIs over FY10-21 was accompanied by increased health care utilization and reliance on PC care, especially same-day surgeries (SDS). PC reliance for SDS increased across body regions from FY10 to its peak in FY20 (Head/Neck: 22.7% to 49.7%, Spine: 37.1% to 57.0%, LE: 38.6% to 51.5%, UE: 40.4% to 53.5%). In FY21, the MHS incurred the highest PC costs for LE MSKIs ($132,242,289), followed by Spine ($98,738,863), UE ($92,118,071), and Head/Neck ($42,718,754).

CONCLUSIONS

To our knowledge, this is the first population study of MSKIs in ADSMs spanning the ICD-10 CM transition (FY15-16) that includes the four Services. Across Services, MSKIs in the U.S. military remain a prevalent and persistent problem. Consistent with prior research, the LE was the most common and costly body region affected by MSKIs. Service members with MSKIs demonstrated an increasing reliance on PC for MSKI care, particularly SDS, over the study period. Expanding future research efforts to include all Services to assess risk factors and patient outcomes for treatments across DC and PC settings is vital to mitigate the threat posed by MSKIs to the readiness of the U.S. Armed Forces.

Lower Extremity Musculoskeletal Injuries in United States Active Duty Service Members: Prevalence/Incidence, Health Care Utilization, and Cost Analysis Spanning Fiscal Years 2016-2021

INTRODUCTION

Lower Extremity musculoskeletal injuries (LE MSKIs) represent a significant portion of overuse injuries in active duty service members (ADSMs). However, variations in study methods and research gaps related to LE MSKIs have prevented Department of Defense (DoD) leaders from assessing the burden of these conditions. The purpose of this study was to report the incidence, prevalence, and types of LE MSKIs sustained by ADSMs across four branches of service and describe associated health care utilization and private sector costs.

MATERIALS AND METHODS

This was a retrospective, longitudinal population study, including ADSMs from the Air Force, Army, Marine Corps, and Navy. Prevalence and incidence rates for LE MSKIs, associated health care utilization, and costs were obtained by querying electronic health records (EHR) from military treatment facilities (MTFs), private sector care (PC) claims, and theater medical data from the Military Health System Data Repository (MDR) from October 1, 2015 to September 30, 2021 (FY16-21). Utilization associated with LE MSKIs in both the direct care (DC) and PC settings was classified into mutually exclusive outpatient encounter categories and acute inpatient stays. PC costs related to LE MSKIs were captured for each year.

RESULTS

In FY21, LE MSKIs occurred in 25.3% of ADSMs (n = 378,615). A higher proportion of females sustained an LE MSKI (33.3%), compared to males (23.7%). From FY16-21, the Army had the highest annual prevalence of LE MSKIs (30.9-35.5%), followed by the Air Force (23.8-31.0%), Marine Corps (23.4-27.0%), and Navy (17.2-19.8%). Incidence rate patterns were similar, with the Army sustaining LE MSKIs at 320 to 377 injuries per 1,000 person-years, followed by the Air Force (241-318), Marines (255-288), and Navy (173-203). Overuse/non-specific MSKIs of the knee were the most common injury type and body region affected, respectively. There were 10,675,543 DC and 1,875,307 PC outpatient encounters from FY16-21 with a primary or secondary diagnosis of LE MSKI. The Air Force was most reliant on PC, with 21.5 to 36.8% of LE MSKI-related encounters occurring outside MTFs during FY16-21. Over $99 million was paid by TRICARE on LE MSKI in FY21 alone with Same Day Surgeries accounting for almost half ($48 million) of this total.

CONCLUSIONS

Among U.S. ADSMs, LE MSKIs remain highly prevalent and costly. We observed disparities across the Services in the prevalence and incidence of LE MSKIs, and their respective reliance on the private sector for management of these conditions. Findings from this work may support military leaders and MSKI researchers who seek to reduce the impact of LE MSKIs on the readiness and overall health of the U.S. Military.

Musculoskeletal Injury Surveillance in the U.S. Military: Analysis of the ICD-10-CM Transition and Descriptive Report of Health Care Utilization at Four Sites Adopting MHS GENESIS

INTRODUCTION

The U.S. Military Health System (MHS) transitioned to the ICD-10-CM coding scheme in October 2015 and began the phased rollout of a new electronic health record system, MHS GENESIS, in October 2017. Both changes have the potential to affect the observed prevalence and health care utilization associated with musculoskeletal injuries (MSKIs) in service members. The purpose of this article was to (1) determine the effect of the ICD-10-CM transition on the observed prevalence of select MSKI conditions and (2) describe MSKI-related health care utilization in four MTFs during the adoption of MHS GENESIS.

MATERIALS AND METHODS

We calculated monthly prevalence rates for six diagnostic groupings of MSKIs routinely seen in the MHS between October 2011 and February 2020. To determine if the transition to ICD-10-CM influenced prevalence rates, we performed an interrupted time series analysis, using the ICD-10-CM transition date (October 1, 2015) as the interruption point. To assess trends in direct and private sector care encounters during the MHS GENESIS transition, we calculated monthly MSKI-related encounters at four MTFs from November 1, 2015 through September 30, 2021.

RESULTS

Three diagnoses had a significant (P < .05) change in the slope, or rate of change, for their monthly prevalence after the introduction of ICD-10-CM (patellofemoral pain syndrome, -0.18; stress fractures, 0.12; subacromial pain, 0.03). These diagnoses also had a significant level change or immediate change in monthly prevalence following the ICD-10-CM transition (patellofemoral pain syndrome, 24.2; stress fractures, 0.16; subacromial pain, 0.36). Three of the four sites adopting MHS GENESIS showed reduced 3-month averages (range: -7.1-13.0%) of MSKI-related encounters following the electronic health record transition. For two of the four MTFs, we observed an increased reliance on private sector immediately leading up to and following the change to MHS GENESIS.

CONCLUSIONS

The observed differences in monthly prevalence for certain MSKIs could be because of the changes in the amount and/or specificity of available codes in ICD-10-CM. Within the six selected diagnostic groupings of MSKIs, we found that patellofemoral pain syndrome, stress fractures, and subacromial pain syndrome demonstrated the greatest changes in prevalence during the ICD-10-CM transition. Those involved in MSKI surveillance should exercise caution when evaluating MSKI prevalence that spans the ICD-10-CM transition. Changes in health care utilization patterns in two of the four MTFs during their adoption of MHS GENESIS suggest that MSKI care may have transferred from direct to private sector care during this period. Future research will be required to validate this finding and determine the impacts on clinical outcomes and military readiness.

Musculoskeletal Injuries in Female U.S. Active Duty Service Members: Prevalence/Incidence, Health Care Utilization, and Cost Analysis Spanning Fiscal Years 2016-2021

INTRODUCTION

Musculoskeletal injuries (MSKIs) are highly prevalent and costly conditions among active duty service members (ADSMs), and female service members sustain these injuries at a higher rate than men. However, lack of women-specific research regarding MSKIs in the U.S. military has limited Department of Defense (DoD) leadership from assessing and addressing the burden of these conditions. The purposes of this study were to report the incidence, prevalence, and types of MSKIs sustained by female ADSMs across the four services in direct care (DC) and private sector care (PC) settings from fiscal years (FYs) 2016 through 2021 and to quantify and describe the health care utilization and private sector costs associated with MSKIs in women over the same period.

MATERIALS AND METHODS

This retrospective, longitudinal population study included ADSMs from the Air Force, Army, Marine Corps, and Navy. Prevalence and incidence rates for Head/Neck, Upper Extremity (UE), Spine, and Lower Extremity (LE) MSKIs in female ADSMs, associated health care utilization, and private sector costs were derived by querying electronic health records from military treatment facilities, PC claims, and theater medical data from the Military Health System Data Repository from October 1, 2015 to September 30, 2021 (FY16-21). Health care utilization associated with MSKIs among female ADSMs for each body region in DC and PC settings was classified into mutually exclusive outpatient encounter categories and acute inpatient stays. PC MSKI-associated costs in service women were captured for each year and categorized by service, body region, and setting.

RESULTS

In FY21, 10.8% (n = 27,976) of female ADSMs sustained Head/Neck MSKI, 16.3% (n = 42,294) UE MSKI, 23.6% (n = 61,048) Spine MSKI, and 33.3% (n = 86,235) LE MSKI. Across the study period, female ADSMs had a 25%-29% higher risk of any MSKI (risk ratio (RR) 1.25-1.29) relative to men. Female soldiers had the highest annual prevalence of MSKIs (62.1%-66.4%), while female Marines had the highest risk of MSKI relative to men (RR 1.40-1.47) for all four major body regions. From FY16 to FY21, the body region with the highest risk of MSKI relative to men was Head/Neck (RR 1.61-1.63), while the region with the lowest relative risk was UE (RR 1.05-1.10). LE MSKIs represented the most common and costly type of injury in female ADSMs, with 406,997 outpatient DC and 87,374 PC encounters in FY21. Total PC costs of LE MSKI for female ADSMs were $30,643,535 in FY21 alone.

CONCLUSIONS

This is the first population-level assessment of MSKI prevalence, incidence rates, health care utilization, and PC costs over a 6-year period for service women in the military health system (MHS). Female ADSMs sustain MSKIs at a higher rate than their male counterparts. Given the critical role of service women in the military, MHS leaders, researchers, and public health officials should continue to explore the underlying causes of these disparities in MSKI rates between the sexes, by expanding research efforts to all services and military settings.

Capturing and Categorizing the Burden of Musculoskeletal Injuries in U.S. Active Duty Service Members: A Comprehensive Methodology

BACKGROUND

Musculoskeletal injuries (MSKIs) represent the most common, costly, and impactful medical conditions affecting active duty service members (ADSMs) of the United States Armed Forces. Inconsistent, variable MSKI surveillance methods and often incompletely described criteria for cohort selection, injuries, incidence, and prevalence have limited efforts to observe longitudinal trends, identify gaps in care, or highlight specific military branches or sites that could benefit from enhanced MSKI intervention protocols. The purpose of this manuscript is to present a comprehensive, well-documented, and reproducible framework for capturing and categorizing MSKI burden, healthcare utilization, and private sector costs for ADSMs across a 12-year period spanning the International Classification of Diseases, 10th Revision, Clinical Modification transition.

METHODS

This was a retrospective, longitudinal population study, including ADSMs from the Air Force, Army, Marine Corps, and Navy. Prevalence and incidence rates for Upper Extremity, Lower Extremity, Spine, and Head/Neck MSKIs, associated health care utilization, and private sector costs were obtained by querying electronic health records from military treatment facilities, private sector care (PC) claims, and theater medical data from October 1, 2010 to September 30, 2021 (Fiscal Years 10-21), using the Military Health System Data Repository. Utilization associated with MSKIs per body region in the direct care and PC settings was classified into mutually exclusive outpatient encounter categories and acute inpatient stays. PC MSKI-associated costs were captured per year and categorized by service, body region, and setting.

CONCLUSIONS

MSKI surveillance research in ADSMs has been impacted by variable, often incompletely described methods. While our approach is not without limitations, our aim was to present a well-documented, reproducible methodology for MSKI investigation in military personnel. By presenting a comprehensive blueprint for capturing and categorizing MSKI care in U.S. service members, our goal is for this methodology to enhance the efforts of researchers, public health officials, and Military Health System leaders to combat MSKIs, the primary medical threat to military readiness.

Allostatic Load Is Associated with Overuse Musculoskeletal Injury during US Marine Corps Officer Candidates School

INTRODUCTION

Overuse musculoskeletal injuries (MSKI) remain a significant medical challenge in military personnel undergoing military training courses; further understanding of the biological process leading to overuse MSKI development and biological signatures for injury risk are warranted. The purpose of this study was to determine the association between overuse MSKI occurrence and physiological characteristics of allostatic load characterized as maladaptive biological responses to chronic stress measured by wearable devices in US Marine Corps officer candidates during a 10-wk training course.

METHODS

Devices recorded energy expenditure (EE), daytime heart rate (HR), sleeping HR, and sleep architecture (time and percentage of deep, light, rapid eye movement sleep, awake time, total sleep). Flux was calculated as the raw or absolute difference in the average value for that day or night and the day or night beforehand. Linear mixed-effect model analysis accounting for cardiorespiratory fitness assessed the association between overuse MSKI occurrence and device metrics ( α = 0.05).

RESULTS

Sixty-nine participants (23 females) were included. Twenty-one participants (eight females) sustained overuse MSKI. Overuse MSKI occurrence in male participants was positively associated with daytime HR ( β = 5.316, P = 0.008), sleeping HR ( β = 2.708, P = 0.032), relative EE ( β = 8.968, P = 0.001), absolute flux in relative EE ( β = 2.994, P = 0.002), absolute EE ( β = 626.830, P = 0.001), and absolute flux in absolute EE ( β = 204.062, P = 0.004). Overuse MSKI occurrence in female participants was positively associated with relative EE ( β = 5.955, P = 0.026), deep sleep time ( β = 0.664, P < 0.001), and percent deep sleep ( β = 12.564, P < 0.001) and negatively associated with absolute flux in sleeping HR ( β = -0.660, P = 0.009).

CONCLUSIONS

Overuse MSKI occurrences were associated with physiological characteristics of allostatic load, including chronically elevated HR and EE and greater time in restorative sleep stages, which may serve as biological signatures for overuse MSKI risk.

Biomechanical and physiological biomarkers are useful indicators of military personnel readiness: a multi-institutional, multinational research collaboration

A ubiquitous problem facing military organisations is musculoskeletal injury (MSKI) risk identification. Recently, two research groups, each with their own funding, collaborated to address this problem. Combining their respective areas of expertise in biomechanics and physiological biomarkers, the group explored this problem in the laboratory and in the field. They have developed a machine learning model in a US Marine Corps (USMC) officer cadet cohort that identifies MSKI risk from a single jump test, identified a minimum inertial measurement unit sensor array to quantity jump and squat performance and have identified sex differences in overuse, lower-limb injury risk. This machine learning model was able to correctly predict lift to place within 4 kg using a testing data set and less than 1 kg in the training set of data. Such collaborative approaches are encouraged to address complicated research problems. To assemble an effective team, consider forming groups that best complement each other's areas of expertise and prioritise securing separate funding to ensure each group can act independently. By doing this, the group has assessed the suitability and feasibility of various wearable technologies, used machine learning to gain insights into USMC physiological training adaptations, and developed an understanding of MSKI risk profiles within this cohort.

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.

Occupational Injuries of Spanish Wildland Firefighters: A Descriptive Analysis

The work of wildland firefighters, especially of the so-called 'Brigadas de Refuerzo contra Incendios Forestales', is characterised by high physical demands and extreme operating conditions. These professionals face long workdays (12 h), walking with heavy loads (~25 kg), being exposed to high temperatures (>30 °C), and handling specialised tools in high-risk environments. This study aimed to describe the prevalence of occupational injuries among members of the 'Brigadas de Refuerzo contra Incendios Forestales' and its relationship to variables such as age and work experience. A total of 217 wildland firefighters (18 female and 199 male) correctly answered a questionnaire developed on an ad hoc basis to meet the study's objectives. A high prevalence of occupational injuries was observed among them (~76%). Age and work experience were shown to be significantly associated with injuries. Individuals over 35 years of age with more than 10 years' experience had a higher probability of injury (OR = 2.14, CI = 1.12-4.06 and OR = 2.46, CI = 1.30-4.67, respectively). Injuries occurred mainly during physical training (~46%), followed by preventive work (~33%) and forest fires (~20%). The most common injuries were tendonitis and muscle pain (~44% and ~21% respectively), followed by sprains (~21%). The results underline the need for physical activity programmes adapted to help wildland firefighters, especially older and more experienced individuals. The identification of risk factors such as age and work experience can contribute to the prevention and management of occupational injuries among this group of highly specialised forestry workers. Specific preventative measures during training are required to mitigate the risk of injury among these crews, who play a crucial role in protecting the environment and public safety.

Musculoskeletal system injuries in the Polish Territorial Defence Forces

BACKGROUND

Musculoskeletal system injuries (MSIs) are the major health problem of soldiers. The aim of this study was to assess the types of MSIs that occurred most frequently among soldiers and which parts of the body they generally affected.

METHODS

The study included 140 Territorial Army soldiers, both men and women, serving in the Polish Territorial Defence Forces (TDF). Times and frequency of MSIs were assessed using an original questionnaire available via a web-based platform, the TDF Information Portal and the Yammer network.

RESULTS

Among the participants, 42% reported MSIs, most often a single one (19%), incurred while doing military service. Damaged muscles and ligaments were the most common injuries in both groups (p>0.05). The knee joint was the main location of injuries for both sexes (24% in men vs 50% in women, p>0.05). Other parts of the body often affected by injuries were the shoulder joint (24%, p>0.05), head, spine, wrist, fingers, ankle and feet (19% each) in the male soldiers and the ankle (24%), spine (14%), head, chest, shoulder joint and foot (10% each) in the female soldiers. Injuries reoccurred with similar frequency in the female and male soldiers (43% vs 40%, p>0.05) and had the same location in both groups (43% vs 40%, respectively, p>0.05). Difficult terrain, too intensive military training and heavy loads were the main risk factors for MSIs in both groups (p>0.05).

CONCLUSIONS

More than half of all the participants (19% of the men and 33% of the women) reported at least one injury incurred during military service. Over 40% of all the study subjects had reinjuries. The males and females were similar in terms of the most common type and location of MSI. Occurrence of MSIs rarely required interruption in the military training/service.

Risk Factors Associated with Musculoskeletal Injuries within the Crew of the Leopard 2 A6 Main Battle Tank Using Inertial Movement Unit Sensors: A Pilot Study

This study aims to assess the musculoskeletal risk of military personnel on a Leopard 2 A6 main battle tank crew and to identify associated factors for future prevention and mitigation strategies. A sample of 57 Portuguese military personnel, who are or were part of the Leopard 2 A6 main battle tank crew, answered a questionnaire on their perception of task performance, considering muscle demands, comfort, posture, movements, and associated symptoms. A subsample of four soldiers from the Armoured Squadron of the Portuguese Mechanized Brigade were assessed using an inertial measurement unit system and underwent a whole-body kinematic analysis coupled with a Rapid Entire Body Assessment during a simulated two-hour mission. The results indicate that soldiers accurately perceive their roles within the crew and that, overall, there is a high risk of musculoskeletal injuries in all tasks. However, tasks directly related to the crew's primary duties carry consistently high risk when considering the time spent on their tasks. This study highlights the need for targeted preventive measures to reduce the incidence and severity of injuries among the crew of the Leopard 2 A6 main battle tank.

Incidence and Risk Factors for Bone Stress Injuries in United States Air Force Special Warfare Trainees

OBJECTIVES

To determine (1) the incidence rate of lower extremity (LE) bone stress injuries (BSIs) in United States Air Force Special Warfare (AFSPECWAR) trainees during the first 120 days of training, and (2) factors associated with sustaining a LE BSI.

DESIGN

Retrospective cohort study.

METHODS

AFSPECWAR Airmen (n = 2,290, mean age = 23.7 ± 3.6 years) entering an intensive 8-week preparatory course "SW-Prep" between October 2017 and May 2021. We compared anthropometric measurements, previous musculoskeletal injury (MSKI), fitness measures, and prior high-impact sports participation in those that did and did not suffer a BSI during the 120-day observation period using independent t-tests and chi-square tests. A multivariable binary logistic regression was used to determine factors associated with suffering a BSI.

RESULTS

A total of 124 AFSPECWAR trainees suffered a BSI during the surveillance period, yielding an incidence proportion of 5.41% and an incidence rate of 1.4 BSIs per 100 person-months. The multivariate logistic regression revealed that lower 2-minute sit-up scores, no prior history of participation in a high-impact high-school sport, and a history of prior LE MSKI were associated with suffering a BSI. A receiver operator characteristic curve analysis yielded an area under the curve (AUC) of 0.727.

CONCLUSION

BSI incidence proportion for our sample was similar to those seen in other military settings. Military trainees without a history of high-impact sports participation who achieve lower scores on sit-ups tests and have a history of LE MSKI have a higher risk for developing a LE BSI during the first 120 days of AFSPECWAR training.

The Value of Strength as a Predictor of Musculoskeletal Injury in Canadian Armed Forces Basic Infantry Candidates

INTRODUCTION

Musculoskeletal injuries (MSKI) impact military organizations by threatening their operational readiness, warranting investigation into relevant factors to inform risk reduction strategies. While several self-reported and physical performance measures have been associated with MSKI among military personnel, few have been validated and none have been reported in Canadian basic infantry candidates. The purpose of this study was to investigate associations between self-reported and physical performance measures and MSKI, and determine their validity as predictors of MSKI, in Canadian basic infantry candidates.

METHODS

This was a planned secondary analysis of a study tracking MSKI at a basic infantry training facility in Ontario, Canada approved by Defence Research & Development Canada. Before the basic infantry training, consenting candidates completed a baseline testing session including self-reported questionnaires, measures of anthropometry, and physical performance previously associated with MSKI (ankle dorsiflexion test, Y-Balance Test, Isometric Mid-Thigh Pull, and the Fitness for Operational Requirements of CAF Employment (FORCE) evaluation). All MSKI reported by candidates were diagnosed by licensed healthcare providers. From a total sample of 129 candidates, 76% (n = 98) were used to determine any associations between baseline testing variables and MSKI and to develop a predictive model (Development Sample), while 24% (n = 33) were used to offer preliminary validation of the same predictive model (Validation Sample). The binary logistic regression and independent sample t-testing determined independent associations with MSKI in the Development Sample. All continuous variables and dichotomous variables previously associated with MSKI risk (Smoker Yes/No, previous history of MSKI, and physical inactivity) were entered into a backward stepwise logistic regression analysis to assess the predictive association with MSKI incidence in the Development Sample. The regression model was then applied to the Validation Sample.

RESULTS

A total of 35 MSKI were diagnosed by Health Services Centre staff. The majority of the MSKI were acute (63%), sustained to the hip, knee, and ankle (74%). The most common diagnoses were strains and sprains (71%). Uninjured participants performed significantly better on the Relative Isometric Mid-Thigh Pull, FORCE 20 mR, FORCE ILS, and FORCE Estimated VO2peak compared to injured participants. Logistic regression analysis showed that the only variable with significant independent association with diagnosed MSKI incidence was self-reported previous history of MSKI. However, the backward stepwise logistic regression analysis retained self-reported previous history of MSKI, FORCE SBD, FORCE Estimated VO2peak, and Isometric Mid-Thigh Pull Peak Force as predictors of MKSI. The logistic regression model including these variables could predict MSKI with an accuracy of 79% in the Development Sample and 67% in the Validation Sample.

CONCLUSION

This study provides preliminary support for the value of measures of absolute muscular strength and cardiorespiratory fitness as predictors of MSKI in Canadian basic infantry candidates. Given the associations between physical performance measures and MSKI, and their necessity during occupational tasks, it is recommended that Canadian basic infantry training facilities integrate resistance training with external loads to best prepare their candidates to meet their occupational demands and potentially minimize MSKI. Further investigations to confirm the predictive capacity of these variables in a larger sample across additional facilities are warranted.

Do Exercise-Based Prevention Programs Reduce Injury in Endurance Runners? A Systematic Review and Meta-Analysis

BACKGROUND

Endurance running is a popular sport and recreational activity yet is associated with a high prevalence of injury. Running related injuries (RRIs) are a leading cause of drop-out and represent a substantial financial burden to runners and healthcare services. There is clear evidence for the use of exercise-based injury prevention programs in games-based and youth sport settings, yet the research investigating the use of exercise to reduce injury risk in endurance runners has not been adequately reviewed recently.

OBJECTIVES

The aim of this review and meta-analysis was to systematically summarize the current research that has investigated the effect of exercise-based prevention programs and their state of supervision on the risk of RRIs in endurance runners.

METHODS

Three databases were searched for relevant studies. Selection and review were completed by two independent reviewers using the following inclusion criteria: (1) study population used endurance running training for health, occupational, or performance outcome(s); (2) participants performed running as their main form of exercise (> 50% of their total training time); (3) study was a randomized controlled trial; (4) a non-running-based exercise intervention was used; (5) a running-only or placebo exercise control group was included; (6) injury rate or incidence was reported; (7) injuries were recorded prospectively alongside the exercise training. Two meta-analyses were conducted using random-effects models, one based on log risk ratio and one based on log incidence rate ratio. The Cochrane Risk of Bias Assessment Tool 2 was used to evaluate the quality of studies and the Grading of Recommendations Assessment, Development and Evaluations approach was employed to grade the certainty of evidence.

RESULTS

A total of nine articles containing 1904 participants were included in analysis. Overall pooled results showed no significant differences between intervention and control groups in injury risk (z = - 1.60; p = 0.110) and injury rate (z = - 0.98; p = 0.329), while a post hoc analysis evaluating supervised interventions only showed that injury risk was significantly lower in the intervention group compared to the control group (z = - 3.75, p < 0.001). Risk of bias assessment revealed that seven studies included in the analysis were of low quality.

CONCLUSIONS

Exercise-based interventions do not appear to reduce the risk and rate of running-related injuries. Supervision may be essential for exercise-based intervention programs to reduce risk of RRIs, possibly due to increased compliance. Studies with more robust designs that include supervised exercise interventions should be prioritized in the future.

TRIAL REGISTRY

Clinical Trial Registration: PROSPERO CRD42021211274.

Can a Psychologic Profile Predict Successful Return to Full Duty After a Musculoskeletal Injury?

BACKGROUND

Psychologic variables have been shown to have a strong relationship with recovery from injury and return to work or sports. The extent to which psychologic variables predict successful return to work in military settings is unknown.

QUESTIONS/PURPOSES

In a population of active duty soldiers, (1) can a psychologic profile determine the risk of injury after return to full duty? (2) Do psychologic profiles differ between soldiers sustaining injuries in the spine (thoracic or lumbar) and those with injuries to the lower extremities?

METHODS

Psychologic variables were assessed in soldiers returning to full, unrestricted duty after a recent musculoskeletal injury. Most of these were noncombat injuries from work-related physical activity. Between February 2016 and September 2017, 480 service members who were cleared to return to duty after musculoskeletal injuries (excluding those with high-velocity collisions, pregnancy, or amputation) were enrolled in a study that tracked subsequent injuries over the following year. Of those, we considered individuals with complete 12-month follow-up data as potentially eligible for analysis. Based on that, approximately 2% (8 of 480) were excluded because they did not complete baseline surveys, approximately 2% (11 of 480) were separated from the military during the follow-up period and had incomplete injury data, 1% (3 of 480) were excluded for not serving in the Army branch of the military, and approximately 2% (8 of 480) were excluded because they were not cleared to return to full duty. This resulted in 450 soldiers analyzed. Individuals were 86% (385 of 450) men; 74% (331 of 450) had lower extremity injuries and 26% (119 of 450) had spinal injuries, including soft tissue aches and pains (for example, strains and sprains), fractures, and disc herniations. Time-loss injury within 1 year was the primary outcome. While creating and validating a new prediction model using only psychological variables, 19 variables were assessed for nonlinearity, further factor selection was performed through elastic net, and models were internally validated through 2000 bootstrap iterations. Performance was deciphered through calibration, discrimination (area under the curve [AUC]), R 2 , and calibration in the large. Calibration assesses predicted versus actual risk by plotting the x and y intersection of these values; the more similar predicted risk values are to actual ones, the closer the slope of the line formed by the intersection points of all subjects is to equaling "1" (optimal calibration). Likewise, perfect discrimination (predicted injured versus actual injured) presents as an AUC of 1. Perfect calibration in the large would equal 0 because it represents the average predicted risk versus the actual outcome rate. Sensitivity analyses stratified groups by prior injury region (thoracic or lumbar spine and lower extremity) as well as the severity of injury by days of limited duty (moderate [7-27 days] and severe [28 + days]).

RESULTS

A model comprising primarily psychologic variables including depression, anxiety, kinesiophobia, fear avoidance beliefs, and mood did not adequately determine the risk of subsequent injury. The derived logistic prediction model had 18 variables: R 2 = 0.03, calibration = 0.63 (95% confidence interval [CI] 0.30 to 0.97), AUC = 0.62 (95% CI 0.52 to 0.72), and calibration in the large = -0.17. Baseline psychologic profiles between body regions differed only for depression severity (mean difference 1 [95% CI 0 to 1]; p = 0.04), with greater mean scores for spine injuries than for lower extremity injuries. Performance was poor for those with prior spine injuries compared with those with lower extremity injuries (AUC 0.50 [95% CI 0.42 to 0.58] and 0.63 [95% CI 0.57 to 0.69], respectively) and moderate versus severe injury during the 1-year follow-up (AUC 0.61 [95% CI 0.51 to 0.71] versus 0.64 [95% CI 0.64 to 0.74], respectively).

CONCLUSION

The psychologically based model poorly predicted subsequent injury. This study does not minimize the value of assessing the psychologic profiles of injured athletes, but rather suggests that models looking to identify injury risk should consider a multifactorial approach that also includes other nonpsychologic factors such as injury history. Future studies should refine the most important psychologic constructs that can add the most value and precision to multifactorial models aimed at identifying the risk of injury.

LEVEL OF EVIDENCE

Level III, prognostic study.

Skeletal muscle adaptations to high-intensity, low-volume concurrent resistance and interval training in recreationally active men and women

This study compared the structural and cellular skeletal muscle factors underpinning adaptations in maximal strength, power, aerobic capacity, and lean body mass to a 12-week concurrent resistance and interval training program in men and women. Recreationally active women and men completed three training sessions per week consisting of high-intensity, low-volume resistance training followed by interval training performed using a variety upper and lower body exercises representative of military occupational tasks. Pre- and post-training vastus lateralis muscle biopsies were analyzed for changes in muscle fiber type, cross-sectional area, capillarization, and mitochondrial biogenesis marker content. Changes in maximal strength, aerobic capacity, and lean body mass (LBM) were also assessed. Training elicited hypertrophy of type I (12.9%; p = 0.016) and type IIa (12.7%; p = 0.007) muscle fibers in men only. In both sexes, training decreased type IIx fiber expression (1.9%; p = 0.046) and increased total PGC-1α (29.7%, p < 0.001) and citrate synthase (11.0%; p < 0.014) content, but had no effect on COX IV content or muscle capillarization. In both sexes, training increased maximal strength and LBM but not aerobic capacity. The concurrent training program was effective at increasing strength and LBM but not at improving aerobic capacity or skeletal muscle adaptations underpinning aerobic performance.

Efficacy of Conservative Interventions for Musculoskeletal Conditions on Pain and Disability in Active Serving Military Personnel-A Systematic Review

INTRODUCTION

Musculoskeletal (MSK) injuries and associated pain disorders are one of the leading causes for soldiers not being medically fit for deployment, impacting force capability and readiness. Musculoskeletal pain continues to be a leading cause of disability within military services and is associated with a substantial financial burden. A better understanding of the effectiveness of MSK pain management strategies is required. This review was designed to determine the efficacy of nonsurgical interventions, such as physiotherapy, exercise, pharmacology, and multidisciplinary programs, to manage MSK conditions in active serving military populations.

MATERIALS AND METHODS

MEDLINE, Embase, CINAHL, and SPORTDiscus were searched to identify relevant randomized clinical trials. Recommended methods were used for article identification, selection, and data extraction. The Cochrane Risk of Bias tool and the Grade of Recommendation, Assessment, Development, and Evaluation were used to appraise the studies. Where possible, meta-analyses were performed. The review was conducted according to the PRISMA guidelines.

RESULTS

Nineteen articles (1,408 participants) met the eligibility criteria. Low back pain (LBP) was the most frequently investigated condition, followed by knee pain, neck pain, and shoulder pain. Early physiotherapy, exercise and adjunct chiropractic manipulation (for LBP), and multidisciplinary pain programs (physiotherapy, occupational therapy, and psychology) (for chronic MSK pain) improved pain (standardized mean difference ranged from -0.39 to -1.34; low strength of evidence). Participation in multidisciplinary pain programs, adjunct chiropractic manipulation, and early physiotherapy improved disability (for LBP) (standardized mean difference ranged from -0.45 to -0.86; low to very low strength of evidence). No studies evaluated pain medication. Dietary supplements (glucosamine, chondroitin sulfate, and manganese ascorbate), electrotherapy, isolated lumbar muscle exercises, home cervical traction, or training in virtual reality showed no benefit. The studies had a high risk of bias, were typically underpowered, and demonstrated high clinical heterogeneity.

CONCLUSIONS

Currently available randomized clinical trials do not provide sufficient evidence to guide military organizations or health care professionals in making appropriate treatment decisions to manage MSK pain in active serving military personnel. Future research is essential to enable evidence-based recommendations for the effective management of MSK pain conditions in this unique population.

Barriers and facilitators to implementation of musculoskeletal injury mitigation programmes for military service members around the world: a scoping review

INTRODUCTION

Musculoskeletal injury (MSK-I) mitigation and prevention programmes (MSK-IMPPs) have been developed and implemented across militaries worldwide. Although programme efficacy is often reported, development and implementation details are often overlooked, limiting their scalability, sustainability and effectiveness. This scoping review aimed to identify the following in military populations: (1) barriers and facilitators to implementing and scaling MSK-IMPPs; (2) gaps in MSK-IMPP research and (3) future research priorities.

METHODS

A scoping review assessed literature from inception to April 2022 that included studies on MSK-IMPP implementation and/or effectiveness in military populations. Barriers and facilitators to implementing these programmes were identified.

RESULTS

From 132 articles, most were primary research studies (90; 68.2%); the remainder were review papers (42; 31.8%). Among primary studies, 3 (3.3%) investigated only women, 62 (69%) only men and 25 (27.8%) both. Barriers included limited resources, lack of stakeholder engagement, competing military priorities and equipment-related factors. Facilitators included strong stakeholder engagement, targeted programme design, involvement/proximity of MSK-I experts, providing MSK-I mitigation education, low burden on resources and emphasising end-user acceptability. Research gaps included variability in reported MSK-I outcomes and no consensus on relevant surveillance metrics and definitions.

CONCLUSION

Despite a robust body of literature, there is a dearth of information about programme implementation; specifically, barriers or facilitators to success. Additionally, variability in outcomes and lack of consensus on MSK-I definitions may affect the development, implementation evaluation and comparison of MSK-IMPPs. There is a need for international consensus on definitions and optimal data reporting elements when conducting injury risk mitigation research in the military.

Effectiveness of Protective Measures and Rules in Reducing the Incidence of Injuries in Combat Sports: A Scoping Review

In recent years, much effort has been made to reduce the injury rate in combat sports. However, the question remains to what extent these measures are effective. Analysis of studies could provide evidence of the effectiveness of measures aimed at reducing the incidence of injuries. This scoping review aims (1) to map research articles dealing with the effectiveness of proper use of protective measures in reducing the incidence of injuries in combat sports; (2) to investigate to what extent the proper use of protective measures and compliance with sports rules help to reduce the incidence of injuries in combat sports; and (3) to identify gaps in the existing literature and suggest future research on this topic. The literature search was conducted on articles published between 2010 and 2023. The main inclusion criteria were studies investigating the effect of sports rules and protective equipment used during training or competition in combat sports on reducing the incidence of injuries. After meeting the criteria, only seven articles from boxing, karate, and taekwondo were included in this study. Results showed that mandatory head guards, along with modern thicker gloves, significantly reduced the rate of knockouts (KOs) and head injuries in boxing despite an increase in the number of head blows. However, the number of facial cuts increased significantly due to the removal of head guards as a piece of mandatory equipment. The use of mouth guards has significantly reduced the number of oral injuries. Changes in rules, such as shortening the duration of bouts, along with the introduction of greater competencies of referees in the supervision of bouts (the standing count, outclassed rule, and medical stops) have helped to reduce the rate of injuries in boxing. The application of a computerised scoring system also contributed to the rate of injuries reduction. The increase in the number of weight divisions had the same effect on U21 karate athletes. However, a higher incentive to attack the head area in taekwondo did not increase the incidence of injuries in youth athletes. It can be concluded that the proper use of protective measures (head and mouth guards) in combination with the rules established for health protection (higher competencies of referees and more weight divisions in competitions) effectively reduces the occurrence of injuries in combat sports. In all Olympic combat sports, the injury incidence should be regularly assessed using the Injury Incidence Rate (IIR) per 1000 min exposures (MEs). Nonetheless, further studies are needed to monitor how established rules (e.g., prohibited behaviour) affect the IIRs.

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.

Association of clinically-measured and dynamic ankle dorsiflexion assessed by markerless motion capture during the drop-jump task on landing biomechanics and risk of ankle injury in military personnel undergoing 10 weeks of physical training

OBJECTIVES

Determine the influence of clinically-measured maximum dorsiflexion, dynamic peak dorsiflexion and percent of clinically-measured maximum dorsiflexion used during a drop-jump task on landing biomechanics and risk of ankle injury in military personnel.

DESIGN

Prospective cohort study.

METHODS

672 participants (122 women) enrolled. The weightbearing lunge test assessed clinically-measured maximum dorsiflexion averaged across limbs (degrees). Markerless motion capture and force plates collected lower extremity kinematic and kinetic data during a drop-jump task. Percent of clinically-measured maximum dorsiflexion used during landing was calculated as dynamic peak dorsiflexion divided by clinically-measured value, multiplied by 100 (%). De-identified injury data was derived from military physical therapists. Simple linear regression analysis determined the association between dorsiflexion measures and landing biomechanics. Simple binary logistic regression analyses identified predictors of ankle injuries. Statistical significance was set at α = 0.05.

RESULTS

Eighteen participants sustained a traumatic ankle injury from a landing. All measures of dorsiflexion were associated with movement patterns that countered the stiff-legged landing strategy with dynamic measures showing a higher predictive value. Protective factors against ankle injury included height (odds ratio: 0.818, p = 0.006) and weight (odds ratio: 0.824, p = 0.023) for women. Relative braking impulse was a risk factor for men (odds ratio: 1.890, p = 0.001).

CONCLUSIONS

Greater clinically-measured and dynamic measures of dorsiflexion were associated with movement patterns that countered the stiff-legged landing strategy but neither measure of dorsiflexion predicted ankle injury risk. Resultant biomechanics and anthropometrics influenced ankle injury risk to warrant recognition for injury prevention initiatives.

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.

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.

ADAPTations to low load blood flow restriction exercise versus conventional heavier load resistance exercise in UK military personnel with persistent knee pain: protocol for the ADAPT study, a multi-centre randomized controlled trial

BACKGROUND

Muscle atrophy, muscle weakness and localised pain are commonly reported following musculoskeletal injury (MSKI). To mitigate this risk and prepare individuals to return to sport or physically demanding occupations, resistance training (RT) is considered a vital component of rehabilitation. However, to elicit adaptations in muscle strength, exercise guidelines recommend lifting loads ≥ 70% of an individual's one repetition maximum (1-RM). Unfortunately, individuals with persistent knee pain are often unable to tolerate such high loads and this may negatively impact the duration and extent of their recovery. Low load blood flow restriction (LL-BFR) is an alternative RT technique that has demonstrated improvements in muscle strength, hypertrophy, and pain in the absence of high mechanical loading. However, the effectiveness of high-frequency LL-BFR in a residential rehabilitation environment remains unclear. This study will compare the efficacy of high frequency LL-BFR to 'conventional' heavier load resistance training (HL-RT) on measures of physical function and pain in adults with persistent knee pain.

METHODS

This is a multicentre randomised controlled trial (RCT) of 150 UK service personnel (aged 18-55) admitted for a 3-week residential rehabilitation course with persistent knee pain. Participants will be randomised to receive: a) LL-BFR delivered twice daily at 20% 1-RM or b) HL-RT three-times per week at 70% 1-RM. Outcomes will be recorded at baseline (T1), course discharge (T2) and at three-months following course (T3). The primary outcome will be the lower extremity functional scale (LEFS) at T2. Secondary outcomes will include patient reported perceptions of pain, physical and occupational function and objective measures of muscle strength and neuromuscular performance. Additional biomechanical and physiological mechanisms underpinning both RT interventions will also be investigated as part of a nested mechanistic study.

DISCUSSION

LL-BFR is a rehabilitation modality that has the potential to induce positive clinical adaptations in the absence of high mechanical loads and therefore could be considered a treatment option for patients suffering significant functional deficits who are unable to tolerate heavy load RT. Consequently, results from this study will have a direct clinical application to healthcare service providers and patients involved in the rehabilitation of physically active adults suffering MSKI.

TRIAL REGISTRATION

ClinicalTrials.org reference number, NCT05719922.

Simultaneous Arthroscopic Glenohumeral Stabilization and Glenoid Microfracture in Young, Active-Duty Military Patients: Outcomes at 5-Year Follow-up

Background

Glenohumeral instability represents a common cause of shoulder pain and disability among active-duty members of the military and is associated with the development of glenoid osteochondral defects.

Purpose

To report clinical outcomes and survivorship after combined microfracture of isolated chondral lesions of the glenoid and labral repair among young, active-duty military patients and to compare outcomes with those of patients who underwent isolated shoulder stabilization.

Study Design

Cohort study; Level of evidence, 3.

Methods

Included were 31 active-duty military patients aged <40 years who underwent simultaneous microfracture of chondral lesions of the glenoid and labral repair for shoulder instability between January 2011 and January 2017 (microfracture group) and 209 patients without chondral defects who underwent shoulder stabilization during the same time period (instability group). Preoperative and 5-year postoperative outcomes (range of motion [ROM], visual analog scale [VAS] for pain, Single Assessment Numeric Evaluation [SANE] score, American Shoulder and Elbow Surgeons [ASES] shoulder score, and Rowe instability score) were compared within and between groups, and separate subgroup analyses were performed to determine whether variant of instability and dominant-shoulder involvement were associated with worse outcomes.

Results

The mean follow-up was significantly longer for the microfracture group versus the instability group (95.58 ± 23.12 vs 83.38 ± 25.93 months; P = .014). Age and sex distributions were similar between groups. In both groups, there was significant pre- to postoperative improvement on all outcomes scores (P = .0001 for all). When compared with the instability cohort, microfracture patients had significantly worse postoperative VAS pain (2.65 ± 1.78 vs 1.55 ± 1.92; P = .003), SANE (79.13 ± 14.43 vs 91.23 ± 13.20; P < .0001), and ASES (79.90 ± 13.87 vs 89.03 ± 14.28; P = .001) scores, as well as decreased ROM in forward flexion (151.29° ± 11.76° vs 155.48° ± 10.3°; P = .039) and external rotation (63.65° ± 8.34° vs 65.17° ± 0.64°; P = .010). At latest follow-up, 58% of microfracture patients had returned to active-duty military service compared with 93.78% of isolated instability patients (P < .0001).

Conclusion

Combined microfracture and arthroscopic labral repair produced modest, albeit statistically significant, improvements in patient-reported outcome measures and may be a reasonable treatment option for patients with chondral lesions who are not candidates for arthroplasty. However, microfracture patients had significantly worse outcomes than patients who underwent stabilization without concomitant chondral defects.

Gender data gap in military research: a review of the participation of men and women in military musculoskeletal injury studies

Servicewomen are at increased risk of musculoskeletal injuries compared with their male counterparts, but women are under-represented in sports medicine research. The aim of this review was to assess the representation of women in military musculoskeletal injury studies. PubMed was searched for human original research studies using the terms Military OR Army OR Navy OR 'Air Force' AND 'musculoskeletal injury' Each study was categorised as epidemiology (basic training), epidemiology (trained personnel), risk factors, interventions and other. The number of male and female participants was retrieved from each study. A total of 262 studies were included: 98 (37%) studies only included men, 17 (6%) studies only included women and 147 (56%) studies included both men and women. A total of 8 051 778 participants were included in these studies (men: 6 711 082, 83%; women: 1 340 696, 17%). The study theme with the greatest proportion of women was musculoskeletal injury epidemiology studies in a basic training population (20% of participants) with the lowest proportion of women in intervention trials (6% of participants). These data suggest women are not under-represented in military musculoskeletal injury studies when considering the gender representation of most militaries. Our data are, however, biased by large epidemiological trials and women were under-represented in intervention trials. The under-representation of women in intervention trials could be due to difficulties in controlling for the effects of female sex steroids on musculoskeletal outcomes, or a focus on interventions in the most arduous military roles where injury risk is highest and women have been previously excluded.

The Influence of Therapeutic Exercise after Ankle Sprain on the Incidence of Subsequent Knee, Hip, and Lumbar Spine Injury

PURPOSE

This study aimed to investigate the burden of knee, hip, and lumbar spine disorders occurring in the year after an ankle sprain and the influence therapeutic exercise (TE) has on this burden.

METHODS

A total of 33,361 individuals diagnosed with ankle sprain in the Military Health System between 2010 and 2011 were followed for 1 yr. The prevalence of knee, hip, and lumbar care-seeking injuries sustained after sprain was identified. Relationships between demographic groups, ankle sprain type, and use of TE with rate of proximal injuries were evaluated using Cox proportional hazard models to determine hazard rate effect modification by attribute. The observed effect of TE for ankle sprain on rate of injury to proximal joints was evaluated using Kaplan-Meier survival analyses.

RESULTS

Of the total cohort, 20.5% ( n = 6848) of patients sustained a proximal injury. Specifically, 10.1% of the cohort sustained a knee ( n = 3356), 2.9% a hip ( n = 973), and 10.3% a lumbar injury ( n = 3452). Less than half of the cohort received TE after initial sprain. Patients that did were less likely to have subsequent knee (HR = 0.87, 95% confidence interval [CI] = 0.80-0.94), hip (HR = 0.68, 95% CI = 0.58-0.79), or lumbar (HR = 0.82, 95% CI = 0.76-0.89) injuries.

CONCLUSIONS

One in five individuals that sought care for an ankle sprain experienced a proximal joint injury in the following year. TE for the management of the initial ankle sprain reduced the likelihood of proximal injury diagnosis and should be considered in treatment plans for return to work and sport protocols after ankle sprains.

Blood Flow Restriction Therapy for Use After Extremity Fracture: A Critically Appraised Topic

CLINICAL SCENARIO

Blood flow restriction (BFR) therapy has emerged as a viable treatment option to enhance clinical recovery in patients with primarily muscular injuries. However, BFR therapy has been rarely investigated in patients with osseous injuries to include extremity fracture.

FOCUSED CLINICAL QUESTION

Does BFR-enhanced therapy improve clinical outcomes in patients during the acute to subacute rehabilitation period after extremity fracture?

SUMMARY OF KEY FINDINGS

(1) In cases of 2 high-performing athletes with talus and osteochondral fracture of the knee, BFR was well tolerated and an effective rehabilitation regimen. (2) In 2 randomized controlled trials evaluating BFR use in patients after operative and nonoperative management of distal radius fractures, pain with activity and self-perceived function were improved in BFR-enhanced therapy as compared with a standard rehabilitation regimen. (3) Objective clinical outcomes including radiographic healing, extremity range of motion, and grip strength evaluated by the randomized controlled trials did not differ significantly between the BFR-enhanced and standard rehabilitation groups.

CLINICAL BOTTOM LINE

BFR-enhanced therapy may improve pain and self-perceived function of the injured extremity during the acute to subacute rehabilitation period after fracture. However, there is not yet a demonstrated benefit of BFR on hastening objective measures of clinical recovery. Large-scale clinical trials comparing BFR-enhanced rehabilitation with standard rehabilitation regimens are needed to better characterize BFR use in patients with osseous injuries.

STRENGTH OF RECOMMENDATION

Two case reports and 2 randomized controlled trials provide level IIB evidence suggesting that BFR may improve pain in the acute rehabilitative stage and improve the patient's perceived function of the injured extremity, without greater improvement in objectively measured clinical parameters as compared with a standard rehabilitation regimen.

The Effects of Early Physiotherapy Treatment on Musculoskeletal Injury Outcomes in Military Personnel: A Narrative Review

The risks and incidence rates of musculoskeletal injuries among military personnel are high, and the importance of physiotherapy in treating these injuries is well established. However, what is less clear is whether the timing of commencement of physiotherapy treatment affects musculoskeletal injury outcomes in military personnel. This lack of clarity is exacerbated by the known underreporting of injuries among military personnel, and the resulting self-management of musculoskeletal injuries using analgesics, non-steroidal anti-inflammatories and other means. This narrative review was designed to identify and synthesize current evidence regarding the effects of timing of physiotherapy treatment on musculoskeletal injury outcomes, focusing on potential benefits of early versus typical or delayed commencement of physiotherapy treatment. Overall, current evidence suggests early physiotherapy treatment of musculoskeletal injuries offers distinct advantages over typical or delayed commencement of physiotherapy treatment in military settings. Specifically, it appears early treatment expedites recovery in early phases following injury onset and benefits longer term mental health and well-being. It may also reduce the need for more invasive and costly health care interventions and enable earlier return to training and operational service. Importantly, a cultural shift within military contexts to ensure early reporting of musculoskeletal injuries is required if the benefits of early commencement of physiotherapy treatment are to be achieved.

Glenoid microfracture in active-duty military patients: minimum 5-year follow-up demonstrates 75% survival

Background

To present midterm patient-reported outcomes and survivorship data of active-duty military patients undergoing microfracture for full-thickness cartilage defects of the glenoid.

Methods

All consecutive patients from January 2013 through December 2016 who underwent glenoid microfracture for full-thickness cartilage injuries with complete outcome scores were identified. Twenty patients met the final inclusion criteria for the study, and all were active-duty military at the time of surgery. A separate subgroup analysis was performed to determine if dominant-shoulder involvement portends worse outcomes.

Results

The mean follow-up was 81.45 ± 19.43 months (range, 60-108). Of the 20 patients, 5 required a secondary surgical procedure within 5 years of their index procedure, with an average time to failure of 45.6 ± 13.15 months. For the 15 patients who did not fail, there was a statistically significant increase in the mean American Shoulder and Elbow Surgeons score (57.20 vs. 88.27, P < .0001) and Single Assessment Numeric Evaluation (45.00 vs. 86.33, P < .0001). Mean pain decreased significantly as measured by the pain visual analog scale (5.40 vs. 1.37, P < .0001). Range of motion in forward elevation, external rotation, and internal rotation did not change significantly postoperatively (P = .4528, .4810, and .1919, respectively). Concomitant procedures did not predict changes in pain, American Shoulder and Elbow Surgeons, or Single Assessment Numeric Evaluation scores. A majority of patients (13/20, 65%) were able to remain on unrestricted military active-duty service, but 7 (35%) underwent medical discharge, including the 5 patients who had experienced treatment failure, plus 2 additional patients.

Conclusion

Glenoid microfracture can result in pain relief and symptomatic improvement for a select group of active-duty military patients, with 75% survivorship at 5 years. Approximately one in three (35%) patients, however, were unable to remain on active-duty military service.

The Association Between Sleep and Musculoskeletal Injuries in Military Personnel: A Systematic Review

INTRODUCTION

Musculoskeletal injuries (MSKIs) are a significant health problem in the military. Accordingly, identifying risk factors associated with MSKI to develop targeted strategies that attenuate injury risk remains a top priority within the military. Insufficient sleep has garnered increased attention as a potential risk factor for MSKI in both civilians and military personnel. Yet, there are no systematic evaluations of the potential association between sleep and MSKI in the military. The purpose of this review is to examine the relationship between sleep and injury in military personnel.

MATERIALS AND METHODS

Literature searches were performed in multiple electronic databases using keywords relevant to sleep quantity and quality, MSKI, and military populations. Two investigators independently assessed the methodological quality of each study using the Newcastle-Ottawa Scale for cohort studies or an adapted form of this scale for cross-sectional studies.

RESULTS

The search yielded 2402 total citations, with 8 studies (3 cohort and 5 cross-sectional) fitting the inclusion criteria. Overall, the systematic review found 5 of the 8 reviewed studies supporting an association between sleep (quality and duration) and MSKI in military personnel. Specifically, poor sleep was associated with increased injury incidence in 2 cohort and 3 cross-sectional studies.

CONCLUSION

This is the first systematic review to evaluate the published literature on the association between sleep and MSKI risk in military populations. Although there is currently limited research on this topic, findings suggest that sleep is associated with MSKI and should be considered when designing strategies aimed at reducing MSKI risk in military personnel.

Unsupervised Clustering Techniques Identify Movement Strategies in the Countermovement Jump Associated With Musculoskeletal Injury Risk During US Marine Corps Officer Candidates School

Musculoskeletal injuries (MSKI) are a significant burden on the military healthcare system. Movement strategies, genetics, and fitness level have been identified as potential contributors to MSKI risk. Screening measures associated with MSKI risk are emerging, including novel technologies, such as markerless motion capture (mMoCap) and force plates (FP) and allow for field expedient measures in dynamic military settings. The aim of the current study was to evaluate movement strategies (i.e., describe variables) of the countermovement jump (CMJ) in Marine officer candidates (MOCs) via mMoCap and FP technology by clustering variables to create distinct movement strategies associated with MSKI sustained during Officer Candidates School (OCS). 728 MOCs were tested and 668 MOCs (Male MOCs = 547, Female MOCs = 121) were used for analysis. MOCs performed 3 maximal CMJs in a mMoCap space with FP embedded into the system. De-identified MSKI data was acquired from internal OCS reports for those who presented to the OCS Physical Therapy department for MSKI treatment during the 10 weeks of OCS training. Three distinct clusters were formed with variables relating to CMJ kinetics and kinematics from the mMoCap and FPs. Proportions of MOCs with a lower extremity and torso MSKI across clusters were significantly different (p < 0.001), with the high-risk cluster having the highest proportions (30.5%), followed by moderate-risk cluster (22.5%) and low-risk cluster (13.8%). Kinetics, including braking rate of force development (BRFD), braking net impulse and propulsive net impulse, were higher in low-risk cluster compared to the high-risk cluster (p < 0.001). Lesser degrees of flexion and shorter CMJ phase durations (braking phase and propulsive phase) were observed in low-risk cluster compared to both moderate-risk and high-risk clusters. Male MOCs were distributed equally across clusters while female MOCs were primarily distributed in the high-risk cluster. Movement strategies (i.e., clusters), as quantified by mMoCap and FPs, were successfully described with MOCs MSKI risk proportions between clusters. These results provide actionable thresholds of key performance indicators for practitioners to use for screening measures in classifying greater MSKI risk. These tools may add value in creating modifiable strength and conditioning training programs before or during military training.

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.

Tibial Bone Geometry Is Associated With Bone Stress Injury During Military Training in Men and Women

Bone stress injuries (BSI) are a common musculoskeletal condition among exercising and military populations and present a major burden to military readiness. The purpose of this investigation was to determine whether baseline measures of bone density, geometry, and strength, as assessed via peripheral quantitative computed tomography (pQCT), are predictive of tibial BSI during Marine Officer Candidates School training. Tibial pQCT scans were conducted prior to the start of physical training (n = 504; Male n = 382; Female n = 122) to measure volumetric bone mineral density (vBMD), geometry, robustness, and estimates of bone strength. Bone parameters were assessed at three tibial sites including the distal metaphysis (4% of tibial length measured from the distal endplate), mid-diaphysis (38% of tibial length measured from the distal endplate), and proximal diaphysis (66% of tibial length measured from the distal endplate). Injury surveillance data was collected throughout training. Four percent (n = 21) of the sample were diagnosed with a BSI at any anatomical site during training, 10 injuries were of the tibia. Baseline bone parameters were then tested for associations with the development of a tibial BSI during training and it was determined that cortical bone measures at diaphyseal (38 and 66%) sites were significant predictors of a prospective tibial BSI. At the mid-diaphysis (38% site), in a simple model and after adjusting for sex, age, and body size, total area [Odds Ratio (OR): 0.987, 0.983], endosteal circumference (OR: 0.853, 0.857), periosteal circumference (OR: 0.863, 0.824), and estimated bending strength (SSI; OR: 0.998, 0.997) were significant predictors of a BSI during training, respectively, such that lower values were associated with an increased likelihood of injury. Similarly, at the proximal diaphysis (66% site), total area (OR: 0.989, 0.985), endosteal circumference (OR: 0.855, 0.854), periosteal circumference (OR: 0.867, 0.823), robustness (OR: 0.007, 0.003), and SSI (OR: 0.998, 0.998) were also significant predictors of BSI in the simple and adjusted models, respectively, such that lower values were associated with an increased likelihood of injury. Results from this investigation support that narrower bones, with reduced circumference, lower total area, and lower estimated strength are associated with increased risk for tibial BSI during military training.

Relationship of footwear comfort, selected size, and lower leg overuse injuries among infantry soldiers

BACKGROUND

High rates of musculoskeletal injuries such as plantar fasciitis and stress fractures have been observed among physically active military personnel. During service time, infantry soldiers use issued boots daily that should fit well and provide comfort to prevent injuries and decrease lower extremity pain effectively. The association of military boot comfort with overuse injuries remains unclear. This study investigates the relationship between the chosen military boot size, perceived boot comfort and lower leg overuse injury.

METHODS

During the cross-sectional study, 227 (males, n = 213; females, n = 14) active-duty infantry soldiers at a mean age of 29.5 years old, and with an average service time of 7.2 years were assessed for a history of overuse injury, footprint length, appropriate shoe size, and footwear comfort. Males with a history of overuse injury (n = 32) and non-injured age-matched controls (n = 34) were selected for detailed testing and establishing the possible relationship between footwear comfort and lower leg overuse injury.

RESULTS

No relationship was found between footwear comfort and a history of lower leg overuse injury. N = 38 (57.6%) of study subjects were wearing an inappropriate shoe size daily. Inappropriate shoe size usage affected footwear comfort ratings significantly.

CONCLUSIONS

Study results showed that improper boot size was significantly related to comfort ratings but was not associated with a history of lower leg overuse injury.

Elevated Kinesiophobia Is Associated With Reduced Recovery From Lower Extremity Musculoskeletal Injuries in Military and Civilian Cohorts

OBJECTIVE

The purpose of this study was to examine associations between level of kinesiophobia and improvement in physical function during recovery from lower extremity injury.

METHODS

A total 430 adults (mean [SD]: age = 27.3 [6.4] years; sex = 70.5% men; body mass index = 27.6 [5.2] kg/m2) were included in the analyses. Using the Patient-Reported Outcomes Measurement Information System, physical function was evaluated in parallel with treatment from a physical therapist at the initial visit and every 3 weeks until final visit or up to 6 months. A Tampa Scale of Kinesiophobia (TSK-17) score of >41 indicated elevated TSK. Four TSK groups were identified: (1) TSK score improved from >41 at initial visit to <41 by final visit (TSK_I), (2) TSK score was <41 at initial and final visits (TSK-), (3) TSK score was >41 at initial and final visits (TSK+), and (4) TSK score worsened from <41 at initial visit to ≥41 by final visit (TSK_W). Linear mixed effects models were used to examine differences between groups in improved physical function over time, with adjustment for depression and self-efficacy.

RESULTS

Groups with elevated kinesiophobia at the final visit had smaller positive improvements in physical function (mean change [95% CI]: TSK+ = 7.1 [4.8-9.4]; TSK_W: 6.0 [2.6-9.4]) compared with groups without elevated kinesiophobia at the final visit (TSK_I = 9.8 [6.4-13.3]; TSK- = 9.7 [8.1-11.3]) by 12 weeks.

CONCLUSIONS

Elevated kinesiophobia that persists or develops over the course of care is associated with less improvement in physical function within military and civilian cohorts.

IMPACT

The findings of this prospective longitudinal study support the need to assess for elevated kinesiophobia throughout the course of care because of its association with decreased improvement in physical function.

LAY SUMMARY

To help improve your physical function, your physical therapist can monitor the interaction between fear of movement and your clinical outcomes over the course of treatment.