MAJ Tanja C. Roy, SP USA

Transcription

1 MILITARY MEDICINE, 176, 8:903, 2011 Diagnoses and Mechanisms of Musculoskeletal Injuries in an Infantry Brigade Combat Team Deployed to Afghanistan Evaluated by the Brigade Physical Therapist MAJ Tanja C. Roy, SP USA ABSTRACT Musculoskeletal injuries are the most common cause for disability in deployed environments. Current research is limited to body region affected by the injury. Objective: To determine the prevalence of musculoskeletal diagnoses and mechanisms of injury (MOI) as well as associations to specific Military Occupational Specialties (MOS) in a deployed Brigade Combat Team (BCT). Methods: Data collected on 3,066 patient encounters by the Brigade Combat Team physical therapist over 15 months were analyzed using descriptive statistics and c 2 tests. Results: Mechanical low back pain was the most common diagnosis (19%), whereas overuse was the most prevalent MOI (22%). The Infantry MOS was significantly associated with meniscal tears and pre-existing injuries, the Maintenance MOS with contusions, Signal and Transportation MOSs with weight lifting injuries, and the Administrative MOS with running injuries. Conclusion: Different MOSs are preferentially susceptible to different diagnoses and MOIs. Therefore, different injury prevention strategies may be needed across occupations. INTRODUCTION U.S. Military Forces are now operating in a constant state of deployment with troops possibly spending a year or more at a time in combat zones. This increase in operational tempo has resulted in a change in the physical demands applied to soldiers, which may lead to an increase in musculoskeletal injuries. Musculoskeletal injuries are the number one reason for seeking medical care in the military and they are the number one cause of medical evacuation from theater. 1 4 Musculoskeletal injuries accounted for 25% of medical evacuations from Afghanistan in 2006, whereas combat injuries accounted for only 7%. 5 These injuries negatively impact military units and reduce their ability to accomplish missions. 4 Currently, there is a lack of available records and specific information pertaining to musculoskeletal injuries occurring while deployed. Electronic notes are not created for many patients or if they are, most of these electronic notes do not upload into accessible databases. This makes it impossible to assess which types of injuries are occurring. At present, physical therapists (PTs) deploy with Combat Support Hospitals (CSH) and Brigade Combat Teams (BCT). Research continues to reaffirm that they have been instrumental in diagnosing and treating musculoskeletal injuries in multiple deployed environments ranging from Korea to the Middle East. 6 9 Military PTs have been so successful that they are considered to be experts on musculoskeletal pathology in deployed environments. 10,11 Because of the lack of electronic medical records in deployed environments, database epidemiological reviews of U.S. Army Research Institute of Environmental Medicine, 15 Kansas Street, Natick, MA The opinions or assertions contained herein are the private views of the author and are not to be construed as official or reflecting the views of the Army or the Department of Defense. Approved for public release; distribution is unlimited. deployed injuries are lacking. PTs are a unique resource available to physically assess musculoskeletal injuries (including both electronic and written encounters) occurring in deployed soldiers in the absence of a comprehensive database. With the high prevalence of musculoskeletal injuries plaguing the military, new injury prevention methods are needed to mitigate and reduce their impact. The initial step in developing prevention methods is surveillance to determine the size of the problem. 12 Current research has established some combination of back, ankle/foot, hand/wrist, knee, and shoulder as the most common body regions to sustain musculoskeletal injuries while deployed. 4,9 This has begun to address this first step of injury prevention by documenting injury prevalence in body regions. What is lacking, however, is subsequent analysis to elucidate which specific diagnoses are occurring and how. With this in mind, the purposes of this study were to determine: (1) the prevalence rate of specific musculoskeletal injuries in an Infantry BCT (IBCT) as seen by the PT over 14 months of the deployment, (2) the most common injuries among soldiers across varying military occupational specialties (MOS), (3) the most common mechanisms of injury (MOI), (4) if there is an association between MOS and diagnosis, and (5) if there is an association between MOS and MOI. METHODS Data were collected on soldiers in the northeast region of Afghanistan in Participants consisted of deployed Army members and included only soldiers seeking medical care. The PT Team (PT plus technician) performed 3,066 patient encounters. Data were collected on all patients seen by the PT Team assigned to an IBCT, the majority of which were direct access, i.e., had no referral. Data included not only the IBCT but also all additional active duty (AD), National Guard, and Army Reserve units in the area of operation. The patients MILITARY MEDICINE, Vol. 176, August

2 included all of the musculoskeletal injuries treated at the Brigade Support Battalion (BSB) Medical Clinic on Forward Operating Base (FOB) Salerno, as well as patients seen by the PT while traveling to eight different FOBs. Average travel time to and from one FOB was 7 days. Because of these challenges, 78% of patients were treated at FOB Salerno, the location of the BSB, Field Artillery Battalion, and Engineer Company. Data did not include musculoskeletal injuries occurring off FOB Salerno unless the PT was physically there to evaluate the patient. As the PT traveled intermittently, the majority of musculoskeletal injuries seen on FOBs other than Salerno were evaluated by other medical providers and not included in the data. Data were collected from March 2006 until May 2007 (excluding February). In February, IBCT consolidated its units in northeast Afghanistan for the remaining 4 months of the deployment, thus patient information was not collected during the move. These data were collected as an injury surveillance project for the brigade; therefore, patient ages and genders are unknown. TABLE I. Variable Body Region Diagnosis MOI MOS Variables Collected on Each Patient. Data Collected Head, Cervical Spine, Shoulder, Chest, Elbow, Wrist, Hand, Thoracic Spine, Lumbar Spine, Hip, Thigh, Knee, Lower Leg, Ankle, and Foot Achilles Tendonitis, Acromioclavicular Joint Separation, Ankle Sprain, Collateral Ligament Sprain, Contusion, Cubital Tunnel, Fracture, Hamstring Strain, Herniated Disk, Iliotibialband Syndrome, Shoulder Impingement Syndrome, Labral Tear, Mechanical Cervical Spine Pain, MLBP, Mechanical Thoracic Spine Pain, Meniscal Tear, Patellar Tendonitis, Plantar Fasciitis, RPPS, and Tibial Stress Reaction/Fracture Combat, Combatives, Convoy Operations, Crush, Dismounted Patrol, Equipment Worn, Fall, Jumping, Lifting for Work, Motor Vehicle Accident, Operation Rehabilitation, Overuse, Physical Training, Pre-existing, Running, Sports, Uneven Terrain, Weight Lifting in the Gym, and Work Unknown Administrative, Air Defense Artillery, Armor, Aviation, Chemical, Construction Equipment, Electronic/Missile Maintainence, Engineers, Finance, Infantry, Intelligence, Maintainence, Medical, Military Police, Signal, Special Equipment, Special Forces, Supply and Logistics, and Transportation Variables Data were retrospectively evaluated from a de-identified patient database. Table I lists the categories collected for body region injured, diagnosis, MOI, and MOS. Additional variables collected were service component (AD, National Guard, and Army Reserve), profile issued, new or followup appointment, FOB, and total patients seen by the BSB Medical Clinic. Data Analysis Descriptive statistics were calculated for all variables. Only first-time patient visits were used in the analyses. Prevalence rates were calculated for body region injured, diagnosis, MOI, and restrictions to duty issued. Restrictions to duty are recorded on forms referred to as profiles in the U.S. Army. Participants were clustered by MOS. MOSs were combined by overall category, for example, soldiers with MOSs of 11B (Infantryman) and 11C (Indirect Fire Infantryman) would be combined as 11 (Infantry). The c 2 values were calculated to determine whether or not significant associations were present between MOS and MOI and between MOS and diagnosis using SPSS 17. The c 2 tests for MOS and MOI compared MOSs with at least 50 participants crossed with MOIs with at least 50 occurrences that were present in each of these MOSs. The c 2 tests analyzed the MOIs of pre-existing, overuse, running, sports, uneven terrain, and weight lifting crossed with the MOSs of Infantry, Engineers, Signal, Military Police, Administrative, Maintenance, Medical, Transportation, and Supply & Logistics. The c 2 tests for MOS and diagnosis was run using MOSs with greater than 45 (Infantry, Engineers, Maintenance, Medical, and Supply & Logistics) crossed with diagnoses greater than 27 (mechanical low back pain [MLBP], ankle sprain, meniscal tear, retropatellar pain syndrome [RPPS], and contusion ). Post hoc testing using standard residuals was used to determine the MOSs and MOIs contributing most to any significant association. No categories with less than 5 participants were identified as significant. RESULTS The PT Team conducted 3,066 patient visits, which represented all of the musculoskeletal injuries treated at the BSB Medical Clinic. These 3,066 visits accounted for 50% of the Medical Clinic s total patient load. Of these, 1,626 were firsttime evaluations and 1,440 were follow-ups or treatments. One thousand two hundred ninety-nine (80%) were direct access, and the remaining 20% were referred to physical therapy by a physician or physician assistant. Patients visited the physical therapy clinic an average of 2.6 times. Out of 1,626 first-time visits, 72% of participants were AD ( n = 1,059), 25% were National Guard ( n = 363), and 3.5% were Army Reserves ( n = 51). The five most frequent MOSs treated were Infantry (13.1%), Engineering (12.8%), Supply & Logistics (11.6%), Maintenance (8%), and Medical (6%). The five most frequently injured body regions among participants were lumbar spine, knee, ankle, foot, and shoulder ( Table II ). Figure 1 shows the top body regions injured for the five most frequently injured MOSs. The Infantry MOS had the highest prevalence of LBP (33%) and the Medical MOS had the least (18%). The Infantry MOS also had the highest 904 MILITARY MEDICINE, Vol. 176, August 2011

3 TABLE II. Percent of Injuries by Body Region in the Data Set Collected from the IBCT in Afghanistan (Absolute Numbers and Percentages, n = 1619). Region Cases Percent Lumbar Spine Knee Ankle Shoulder Foot Cervical Spine Hand Elbow Wrist Thoracic Spine Hip Lower Leg Thigh Chest Arm TABLE III. Top 15 Diagnoses Treated by the IBCT PT and Percentage of Total Diagnoses ( n = 1,520). Diagnosis Cases Percent MLBP Ankle Sprain RPSS Contusion Plantar Fasciitis Meniscal Tear Mechanical Cervical Pain Impingement Herniated Disk Fracture Patellar Tendonitis Tibial Stress Reaction Labral Tear Iliotibial Band Syndrome Mechanical Thoracic Spine Pain Acromioclavicular Separation Hamstring Strain Cubital Tunnel Syndrome Achilles Tendonitis Pectoralis Strain FIGURE 1. Body regions injured by MOS. prevalence of knee injuries (26%). Elbow, wrist, and hand injuries were more common in the Engineers and Maintenance MOSs. Shoulder injuries were the most prevalent in Engineers (12%). The five most commonly diagnosed injuries were MLBP, ankle sprains, RPPS, contusions, and plantar fasciitis ( Table III ). Each MOS had different prevalence rates for injuries ( Fig. 2 ). The Infantry and Medical MOSs suffered more meniscal tears. Most meniscal tears were attributed to a loss of footing during patrols or an exacerbation of a pre-existing condition. Engineers had the highest percentage of impingement syndrome and contusions. The Maintenance MOS had the highest prevalence of herniated disks (HNP). The Medical MOS had the highest prevalence of mechanical cervical pain (MCP). MLBP was the most common diagnosis in all MOSs. The c 2 analysis showed a significant association (c 2 = 33.99, p < 0.005) between MOS and diagnosis. Post hoc testing indicated that the Infantry MOS was significantly associated with meniscal tears and the Maintenance MOS was significantly associated with contusions. FIGURE 2. Diagnoses by MOS. These are compared as percentages of the total diagnoses in each MOS. The five most common MOIs were overuse (22%), exacerbations of pre-existing conditions (12%), weight lifting in the gym (8%), sports (8%), and traversing uneven terrain (7%) ( Table IV ). Weight lifting was a major cause of injury in all of the top five MOSs and sports was a leading MOI in four of the top five MOSs ( Fig. 3 ). Infantry suffered much fewer sports injuries than other MOSs ( Fig. 3 ). 16% of injuries were caused by sports and weight lifting (nonduty-related activities) ( Table IV ). The c 2 analysis showed a significant association (c 2 = 89.75, p < 0.001) between MOS and MOI. Post hoc testing indicated that Infantry and Supply & Logistics MOSs were significantly associated with pre-existing/chronic injuries, Signal and Transportation MOSs were significantly associated with weight lifting injuries, and the Administrative MOS was significantly associated with running injuries. MILITARY MEDICINE, Vol. 176, August

4 TABLE IV. Top 15 MOI and Percentage of Total MOI, n = 1,626. PT is Physical Training and is Conducted Under the Supervision of a Member of the Unit Chain of Command. The Top 15 MOIs Result in 82.5% of the Total MOIs. MOI Cases Percent Overuse Pre-existing Weight Lifting Sports Uneven Terrain Running Fall Lifting Work Crush PT (Not Running) Work Unknown Combat Motor Vehicle Accident Combatives Running TABLE V. Top 5 Diagnoses Resulting in Restrictions of Duty (Profile) for all Data Collected. Profiles by Diagnosis Diagnosis Cases Percent of Profiles Percent of Injury MLBP Ankle Sprain Contusion RPSS Meniscal Tear FIGURE 4. Top five MOI resulting in restrictions of duty (profiles) for all data collected. FIGURE 3. MOIs by MOS. These are compared as percentages to the total MOI in each MOS. Four hundred sixty-four (28.5%) of soldiers reporting for first-time visits were issued a restriction to duty, profile. Three hundred nine (19%) of these profiles restricted the soldier s ability to work, whereas the remainder restricted their level of physical training. 30.1% of AD soldiers seen for an injury were issued a profile, whereas this percentage was 21.5% for Army Reservists and 29.2% for National Guardsmen. Table V and Figure 4 show meniscal tears and running as resulting in more profiles than 80% of the other injuries and MOIs; however, neither of these were the most prevalent injuries or MOIs. DISCUSSION By using data collected from the BCT PT, we were able to collect data on diagnoses, MOIs, and MOS that heretofore have been difficult to capture. With the paucity of accurate electronic records for injuries occurring while deployed, these data provide a new level of information on causation of musculoskeletal injuries. Currently, musculoskeletal injuries are tracked simply as an overarching category. In most current studies, musculoskeletal injuries are not broken down beyond musculoskeletal injury vs. illness or respiratory infection. In a few cases, they are separated into body region injured. This study expands on the typical body region analysis from current literature and provides a more in-depth analysis of musculoskeletal diagnoses and MOIs occurring in deployed environment within different MOSs. These data display unique trends in body regions injured. Lower extremity injuries were higher in Afghanistan (39.4%) than what has been reported for other areas, especially Bosnia (28.5%) and the United States (29.2%). 8,13 The area of Afghanistan in which the IBCT was operating was mostly rugged hilly terrain. Additionally, FOBs in Afghanistan are covered with rocks artificially creating uneven terrain. This uneven terrain may have led to the increase in lower extremity injuries seen in Afghanistan. Shoulder injuries and thoracic spine injuries were much lower in Afghanistan (10.1%) than in Iraq (17.0%). 9 This could be due to the fact that the 906 MILITARY MEDICINE, Vol. 176, August 2011

5 unit from Iraq wore deltoid protectors and side plates, whereas the one in Afghanistan did not. This additional weight and possibly altered shoulder biomechanics may have led to a higher prevalence of shoulder and thoracic injuries. Finally, back pain is much more prevalent while deployed (21.2% in Afghanistan, 26.9% in Bosnia, and 23.2% in Iraq compared to 17.8% [includes back and abdomen] in nondeployed military members).8,9,13 Deployed Maintenance soldiers suffered from 27% LBP in this study as compared to 19% in the U.S., the ratio for Engineers was 23% compared to 16% and Infantry was 32.6% compared to 11.6% This study offers new information by analyzing beyond body region injured and assessing which diagnoses were more common within specific MOSs. The Infantry MOS was significantly associated with meniscal tears. They operated off the bases wearing their individual body armor in very mountainous terrain. Many of those with meniscal tears reported a loss of footing during patrols or an exacerbation of a pre-existing condition as the cause of the injury. The Maintenance MOS was significantly associated with contusions. These soldiers spend their time manipulating parts to repair equipment. Even though their job is similar while serving in the U.S., they suffered almost double the contusions as compared with a nondeployed Maintenance unit. 14 The Maintenance MOS also suffered the most HNPs. They are required to work bent over and need to lower and raise parts in and out of engines. This could explain the large number of HNPs seen only in this MOS. 17 Engineers and Maintenance MOSs had the highest percentage of shoulder impingement syndrome. Their mission tasks involve a large amount of upper extremity use likely leading to these injuries. 18 Interestingly, they are suffering more injuries while deployed with a rate of 25% upper extremity injuries in Afghanistan but only 15% in a nondeployed Engineer unit. 15 Perhaps the most important novel data generated by this study are the MOIs leading to musculoskeletal injury while deployed to Afghanistan. The most common cause of injury was overuse followed by exacerbations of pre-existing conditions and weight lifting. This is different than the most common MOIs seen in nondeployed Army members, which are falls, vehicle accidents, and sports. 19 Soldiers are required to work 6 to 7 days a week while deployed, thus resulting in overuse as a common cause of injury. A deployed Infantry unit suffered 12.4% overuse injuries compared to a nondeployed Infantry unit, 5.6%. 20 Although wearing an armored vest for 1 day may not cause an injury, wearing one for 4 hours a day every day (overuse) does correlate with injury. 21 Exacerbation of pre-existing conditions was the second most common cause of injury for all soldiers and Infantry and Supply & Logistics MOSs were significantly associated with pre-existing/chronic injuries ( Fig. 3 ). Deployed Maintenance soldiers suffered from twice as many exacerbations of pre-existing conditions compared to a nondeployed Maintenance unit. 14 Finally 6% of injuries were caused by a nonduty-related activity, namely weight lifting. In fact, Signal and Transportation MOSs were significantly associated with weight lifting injuries. With the high prevalence of musculoskeletal injuries and the restrictions to duty they cause (19%), methods for injury reduction need to be investigated. 10% of musculoskeletal injuries in this study were caused by sports ( Table IV ). This can be compared to 11.4% in nondeployed Army members during 2006 and 22% in deployed military members in ,22 Infantry mostly operate on smaller more austere bases and seldom if ever have the opportunity to play sports thus it stands to reason that sports would not be a major MOI for them ( Fig. 3 ). In fact, these deployed Infantry soldiers suffered 2.1% of injuries from sports and weight lifting as compared to 8% seen in a similar nondeployed sample. 16 The Infantry clearly suffered less injuries when sports were less available. Reducing or removing sports in a deployed environment may be a method of reducing musculoskeletal injuries. The second most common cause of injury was pre-existing or chronic conditions. Untreated injuries potentially develop into these chronic injuries. Specialized medical care may not be readily available to all soldiers. These results suggest an increased effort may be needed to treat initial injuries earlier and with more specialized care to reduce chronic problems. 23,24 With only one PT per brigade, it is not possible to offer musculoskeletal specialty care to all brigade soldiers. Traveling from FOB to FOB in mountainous Afghanistan was exceedingly challenging and time consuming making it difficult to provide soldiers access to this musculoskeletal expert. In cases where brigades are spread across multiple FOBs, it may be beneficial to incorporate more than one PT per brigade to increase access to specialty care, reduce chronic injuries, and promote injury prevention techniques. It may be beneficial to increase the number of PTs in all brigades. The patients treated by the PT in this study comprised 50% of the total Medical Clinic patient load. This can be compared to 16.4% treated by the PT in the 21st Combat Support Hospital in Bosnia and 31.6% seen by a BCT PT in Iraq. 8,9 The sample included in this study is a sample of convenience and was analyzed using a retrospective review. This is a limitation of the study. The records analyzed for this study included only those musculoskeletal injuries treated by the Brigade PT and not all musculoskeletal injuries occurring in the IBCT. The PT treated almost all musculoskeletal injuries occurring on the largest IBCT FOB, FOB Salerno. A small amount were treated by the Field Artillery PA and not referred to the PT. The records included from eight of the smaller IBCT FOBs were of patients evaluated by the PT when she traveled. Most patients on these outlying FOBs were evaluated by the PA permanently stationed at the FOB; thus, their records were not available. Despite these limitations, this study included a very robust sample size including all major MOSs found in an IBCT and captured data not available by electronic review. CONCLUSION This study confirms that musculoskeletal injuries are a considerable problem for deployed units. In addition, specific diagnoses and MOIs were quantified in specific occupations. MILITARY MEDICINE, Vol. 176, August

6 The Infantry MOS suffered significantly more meniscal tears and pre-existing injuries, the Maintenance MOS suffered significantly more contusions, Signal and Transportation MOSs suffered significantly more weight lifting injuries, and the Administrative MOS had significantly more running injuries than other MOSs. With this more comprehensive and mechanistic injury information, better injury prevention programs can be designed to reduce musculoskeletal injuries. ACKNOWLEDGMENTS Funding was supplied by the U.S. Army Research Institute of Environmental Medicine under Task Area S. REFERENCES 1. Clark ME, Bair MJ, Buckenmaier CC 3rd, Gironda RJ, Walker RL : Pain and combat injuries in soldiers returning from Operations Enduring Freedom and Iraqi Freedom: implications for research and practice. 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