Comparison of stress fractures of male and female recruits during basic training in the Israeli anti-aircraft forces

BACKGROUND: In military basic training, stress fractures are a common orthopedic problem. Female recruits have a significantly higher incidence of stress fractures than do male recruits. Because the Israeli Defense Forces opened traditionally male roles in combat units to female recruits, their high risk for stress fractures is of concern. OBJECTIVE: To compare the prevalence of stress fractures during Israeli Defense Forces anti-aircraft basic training among otherwise healthy young male and female recruits, in terms of anatomic distribution and severity. DESIGN: Ten mixed gender batteries, including 375 male recruits and 138 female recruits, carried out basic training in the Israeli anti-aircraft corps between November 1999 and January 2003. Each battery was monitored prospectively for 10 weeks of a basic training course. During that time, recruits who were suspected of having an overuse injury went through a protocol that included an orthopedic specialist physical examination followed by a radionuclide technetium bone scan, which was assessed by consultant nuclear medicine experts. The assessment included the anatomic site and the severity of the fractures, labeled as either high severity or low severity. RESULTS: Stress fractures were significantly more common among female recruits than among male recruits. A total of 42 male (11.2%) and 33 female (23.91%) recruits had positive bone scans for stress fractures (female:male relative ratio, 2.13; p < 0.001). Pelvic, femur, and tibia fractures were significantly more common among female recruits than among male recruits (p < 0.005). Female recruits had significantly more severe fractures in the tibia (p < 0.05). However, there was no significant difference in the severity of stress fractures in the femur or metatarsals between male and female recruits, as assessed by radionuclide uptake. CONCLUSIONS: We recommend that different training programs be assigned according to gender, in which female recruits would have a lower level of target strain or a more moderate incline of strain in the training program throughout basic training.     

The long-term followup of soldiers with stress fractures

A group of 295 Israeli infantry recruits was evaluated in a prospective study of stress fractures which began in basic training. On the basis of scintigraphy, 91 of the recruits (31%) were found to have sustained stress fractures during basic training. Sixty-six of the 91 recruits with stress fractures (72%) were followed for a minimum of 1 year after basic training to determine the natural history of a soldier who sustains a stress fracture and resumes training after a period of rest. Five clinical patterns were observed: (1) uneventful recovery (47%); (2) protracted recovery (13.6%); (3) symptoms consistent with recurrent stress fractures in new sites (19.6%); (4) intermittent nonstress fracture bone pain (16.7%); and (5) chronic stress fractures (3%). The incidence of recurrent stress fractures was 10.6%. A control group of 60 recruits who sustained no stress fractures in basic training had a 1.7% incidence of stress fractures after basic training. Recruits who sustained stress fractures in basic training continued to be a higher risk for stress fractures during subsequent training.     

Prevention of common overuse injuries by the use of shock absorbing insoles. A prospective study

Sedentary individuals, particularly new military recruits, who start a physical training program have a substantial risk of developing an overuse injury of the lower limb. In this study we investigated the effect of neoprene insoles on the incidence of overuse injuries during 9 weeks of basic military training. The experimental group consisted of 237 randomly selected new recruits, while 1151 recruits were the control group. Insoles were given to the experimental group and compliance was monitored. A panel of doctors documented and classified all injuries occurring during the 9 week period. A total of 54 (22.8%) and 237 (31.9%) injuries were reported in the experimental and control groups, respectively. In both groups, the majority of injuries were overuse (experimental group, 90.7%; control group, 86.4%). The mean weekly incidence of total overuse injuries and tibial stress syndrome was significantly lower (P less than 0.05) in the experimental group. The mean incidence of stress fractures was lower in the experimental group but not significantly so (0.05 less than P less than 0.1). This study shows that the incidence of total overuse injuries and tibial stress syndrome during 9 weeks of basic military training can be reduced by wearing insoles.     

Clinical value of grading the scintigraphic appearances of tibial stress fractures in military recruits.

PURPOSE: This study evaluated the relation between the scintigraphic appearances of tibial stress fracture in military recruits and the likelihood that they would complete basic military training. MATERIALS AND METHODS: The authors retrospectively reviewed 58 Tc-99m MDP scans of recruits referred for possible tibial stress fracture and graded them according to the criteria of Zwas et al. (1987). Stress fracture appearances were correlated with clinical information such as the duration of rehabilitation and final outcome with regard to completion of the initial basic military training program. RESULTS: Thirty-seven of the 58 patients (64%) had tibial stress fractures, all of which were located in the tibial diaphysis, with most occurring in the middle and lower thirds. Most (23 of 37) patients had stress fractures of grade I or II, and the others had grade III or IV stress fractures. There was no statistical difference in the proportion of patients with bilateral fractures between grades I-II and III-IV. There was no significant difference in the duration of rehabilitation for recruits successfully recovering from grade III-IV fractures compared with grade I-II fracture. There was a greater proportion of patients with lower grade fractures than higher grade fractures (P = 0.0006) who, despite rehabilitation, could not continue training because of unremitting or recurring pain at the fracture site and were medically discharged from military service. CONCLUSIONS: Contrary to expectation, recruits with higher-grade stress fractures were not less likely to complete basic military training compared with recruits with lower grade stress fractures.     

The incidence and risk factors in the development of medial tibial stress syndrome among naval recruits

PURPOSE: To identify the incidence of medial tibial stress syndrome (MTSS) in a group of naval recruits undergoing a 10-week basic training period and to determine potential risk factors. METHOD: One hundred and twenty-four recruits (84 men and 40 women) were followed prospectively during basic training. Anthropometric and lower limb biomechanical data were recorded at the start of the program along with injury history and previous sporting activity for the 3 months prior to enlisting. Recruits were monitored during training for development of medial tibial strees syndrome and were asked to complete an exit interview at the end of the program. RESULTS: Forty recruits (22 men and 18 women) developed medial tibial stress syndrome, giving an incidence of 35%. A significant relationship existed between gender and medial tibial stress syndrome (P =.012), with female recruits more likely to develop medial tibial stress syndrome than male recruits (53% vs 28%). A risk estimate revealed a relative risk of 2.03. The biomechanical results indicated a more pronated foot type (P =.002) in the medial tibial stress syndrome group when compared to the control group. A risk estimate established that recruits with a more pronated foot type had a relative risk of 1.70. CONCLUSION: Identifying a pronated foot type prior to training may help reduce the incidence of medial tibial stress syndrome by early intervention to control abnormal pronation. Findings of a higher incidence of medial tibial stress syndrome among female recruits require further investigation.     

Are overground or treadmill runners more likely to sustain tibial stress fracture?

BACKGROUND: Repetitive high bone strain and/or strain rates, such as those that occur during running, contribute to stress fractures as well as promoting maintenance of or increase in bone mass. Kinematic differences are known to exist between overground and treadmill running and these may be reflected in different bone strains and strain rates during the two running techniques. Aim: To measure in vivo strains and strain rates in human tibia during treadmill and overground running and determine if there are significant differences in strain and strain rate levels between the two running techniques. METHODS: A strain gauged bone staple was mounted percutaneously along the axial direction in the mid diaphysis of the medial tibia in three subjects, and in vivo tibial strains were measured during treadmill and overground running at 11 km/h. RESULTS: Axial compression strains (p<0.0001), tension strains (p<0.001), compression strain rates (p<0.0001), and tension strain rates (p<0.0001) were 48-285% higher during overground running than during treadmill running. CONCLUSIONS: On the basis of lower in vivo strains and strain rates, treadmill runners are at lower risk of developing tibial stress fractures, but less likely to achieve tibial bone strengthening, than overground runners.     

Lower limb pain and disability following strenuous activity

One hundred five military recruits were evaluated in our outpatient clinic for pain in the lower limb following prolonged sustained physical effort and strain. Plain x-ray investigations augmented by technetium-99m polyphosphate demonstrated the presence of 80 stress fractures in 52.4% of the patients. None of the patients had any anatomical abnormalities of the lower limbs. Of the stress fractures seen, 82.5% were located in the tibial and femoral diaphyses and 16.2% were in the small bones of the foot. Plain radiography gave false negative results in 87.3% of documented fractures. The remaining 47.6% of these recruits had no evidence of stress fractures. However, 74% of them had various anatomical deformities of the lower limb, mainly of the feet. Correction of these deformities enabled these patients to return to previous strenuous activities of their basic military training. The pathogenesis of stress fractures is still not understood. However, the development of persistent pain in the lower limb following prolonged sustained intensive physical activity needs further investigation. Anatomical deformities may be associated with development of stress fractures.     

Effects of ball sports on future risk of stress fracture in runners.

OBJECTIVE: To evaluate whether playing ball sports during childhood and adolescence is associated with the risk of stress fractures in runners later in life. DESIGN: Retrospective cohort study. SETTING: National track and field championships, held at Stanford University. PARTICIPANTS: One hundred fifty-six elite female and 118 elite male distance runners, age 18 to 44 years. INTERVENTIONS: A 1-page questionnaire was used to collect data regarding ages during which athletes played basketball and soccer, as well as other important covariates and outcomes. OUTCOME MEASUREMENTS: Athletes reported the ages when stress fractures occurred. Time to event was defined as the number of years from beginning competitive running to the first stress fracture or to current age, if no fracture had occurred. RESULTS: In both men and women, playing ball sports in youth correlated with reduced stress fracture incidence later in life by almost half, controlling for possible confounders. In men, each additional year of playing ball sports conferred a 13% decreased incidence of stress fracture (adjusted hazard ratio [HR] and 95% confidence interval, 0.87 [0.79-0.95]. Among women with regular menses, the HR for each additional year of playing ball sports was similar: 0.87 (0.75-1.00); however, there was no effect of length of time played among women with irregular menses (HR, 1.03 [0.92-1.16]). In men, younger ages of playing ball sports conferred more protection against stress fractures (HR for each 1-year-older age at first exposure, 1.29 [1.14, 1.45]). CONCLUSIONS: Runners who participate during childhood and adolescence in ball sports may develop bone with greater and more symmetrically distributed bone mass, and with enhanced protection from future stress fractures.     

Medial tibial stress fracture diagnosis and treatment guidelines

ObjectivesTo validate and make evidence based changes to the Israel Defense Forces medial tibial stress fracture diagnosis and treatment protocol.DesignProspective cohort study.Methods429 Elite infantry recruits were reviewed for signs and symptoms of medial tibial stress fracture during 14 weeks of basic training. Suspicion of medial tibial stress fracture was based on the presence of pain, tenderness <1/3 the length of the tibia and a positive fulcrum and/or hop test. Recruits with suspected medial tibial stress fractures were initially treated with 10–14 days of rest. Bone scan was performed only when recruits failed to respond to the rest regimen or required immediate diagnosis.Results31 Out of 49 recruits with a suspicion of medial tibial stress fracture underwent bone scan, including 8/26 recruits whose symptoms did not resolve after being treated clinically as stress fractures. There was a significantly greater incidence of medial tibial stress fractures when a positive hop test was present in addition to tibial pain and tenderness (p = 0.0001), odds ratio 52.04 (95% CL, 2.80–967.74). Medial tibial stress fracture was found to occur when the band of tibial tenderness was ≤10 cm in length. Tibial pain scores were not predictive of stress fracture.ConclusionsThis validation study provides the clinician with evidence based guidelines for the clinical diagnosis and treatment of medial stress fractures and their differentiation from shin splints. An initial treatment protocol without the use of imaging was found to be effective in more than two-thirds of the cases.     

The effect of leg strength on the incidence of lower extremity overuse injuries during military training

This study examined the effects of strength, aerobic fitness, and activity profile on the incidence of overuse injuries, particularly stress fractures, during military training. A total of 136 military recruits were followed during 9 weeks of basic training. Maximal strength and aerobic fitness were determined by a one-repetition maximum leg press and a 2,000-m run, respectively. An activity profile was determined by the recruit's activity history. Twelve recruits (8.8%) were diagnosed with stress fractures. Recruits who were 1 SD below the population mean in both absolute (98.4 +/- 36.6 kg) and relative strength (1.72 +/- 0.61 kg/kg of body weight) had a five times greater risk for stress fracture (p < 0.05) than stronger recruits. Poor aerobic fitness did not appear to be related to any increased incidence of stress fracture. It appears that recruits with lower body strength levels, within 1 SD of the population mean, have a reduced incidence of stress fractures during military training.     

Stress fractures. Identifiable risk factors.

To answer the question why such large differences in stress fracture morbidity rates (2% to 64%) exist in different countries, we prospectively evaluated 312 recruits for possible risk factors for stress fractures. Prior to training, each recruit underwent an evaluation including the following: orthopaedic examination, foot and tibial radiographs, measurements of tibial bone width, bone mineral content, bone density, aerobic physical fitness and leg power, assessments of somatotype and smoking habits, and evaluation of sociological and psychological factors. Using a multivariate analysis, two risk factors were identified: recruits with stress fractures had significantly narrower tibiae (P less than 0.001), and a higher degree of external rotation of the hip (P = 0.016). These two variables were independent and cumulative. Stress fracture morbidity was 17%, 29%, and 45% when neither, one, or both risk factors were present, respectively (P less than 0.001). Identification of these risk factors might explain the susceptibility of some people to stress fractures.     

Stress fractures of the pelvis in female navy recruits: an analysis of possible mechanisms of injury

The purpose of our study was to investigate possible risk factors and mechanisms for the development of pelvic stress fractures in female Navy recruits. We used a case-control retrospective study of female Navy recruits undergoing basic military training. We compared anthropometric and activity data between recruits with pelvic stress fractures (N = 25) and female recruits who completed training without injury (N = 61). Recruits developing pelvic stress fractures were significantly (p < 0.05) shorter and lighter and were more frequently Asian or Hispanic than recruits without stress fractures. In addition, recruits with pelvic stress fractures reported marching in the back of their training division, were road guards, and felt that their stride was too long during training activities more often than recruits without injury. Self-reported fitness, activities before recruit training, or a history of amenorrhea was not found to be associated with the development of a pelvic stress fracture in our population.     

Negative bone scans in impending tibial stress fractures. A report of three cases

Three highly motivated military recruits who presented with tibial pain on exertion are reported. Their initial bone scan assessments to rule out stress fracture were normal, and the recruits were returned to demanding training. One month later, because of persistent and increasing tibial pain, they were rescanned and focal activity representative of tibial stress fractures was found in each case. Until now it has been assumed that a negative bone scan ruled out a stress fracture unequivocally. Our reported cases show that bone pain may in fact precede scintigraphic evidence of a stress fracture. Persistent and increasing bone pain during demanding physical activity, even in the presence of a prior normal bone scan, may represent stress fracture and repeat bone scan may be indicated.     

Fractures in the collegiate athlete

PURPOSE: To determine the demographics and incidence of fractures in collegiate athletes. STUDY DESIGN: Retrospective review of prospectively collected data. METHODS: Division I collegiate athletes who sustained a fracture while enrolled at the university from 1986 to 2000 were identified through training room records. Type and location of fracture, sport, gender, age, position, height, and weight were recorded and analyzed. Team information was obtained from athletic department records and was used to calculate incidence. RESULTS: Between 1986 and 2000, 5900 Division I athletes at our institution sustained 349 primary fractures (5.9%). By gender, the incidence did not differ significantly between males and females (P =.236), except in water polo where the men sustained significantly more fractures. By type, females sustained significantly more stress fractures (P =.001) than males. Overall, by location, the hand contributed the greatest number of total fractures. By sport, the incidence rate was highest in basketball (0.081) for male athletes and in gymnastics (0.069) for female athletes. The incidence of a second fracture during the study period was twice the rate of the first fracture. CONCLUSIONS: As expected, athletes participating in contact sports contributed the greatest number of fractures. Participation in basketball for men and in gymnastics for women posed the greatest risk. Female athletes sustained significantly more stress fractures.     

Stress fracture in parachute regiment recruits

A survey of stress fractures occurring in recruits at the Depot of The Parachute Regiment was carried out over a one year period from July 1985 to August 1986. A total of 44 fractures in 36 soldiers were diagnosed. The incidence was thus 4.84%, much lower than that found in a recent prospective Israeli study. Only one case of progression to complete fracture was observed during the study. In contrast to the previous experience with British recruits, the commonest site of stress fracture was the tibial midshaft.     

The role of biomechanical shoe orthoses in tibial stress fracture prevention

BACKGROUND: Biomechanical orthoses have been shown to lower stress fracture incidence in infantry recruits. However, these results may not be applicable to running athletes. HYPOTHESIS: Training in either running shoes or military boots with custom biomechanical shoe orthoses lessens tibial bone strains and strain rates during walking and running. STUDY DESIGN: Randomized controlled laboratory study. METHODS: In vivo strain measurements were made in nine subjects to determine whether the use of biomechanical orthoses lowers tibial strains during both walking and running and whether such lowering depends on the type of shoe worn. Measurements were made during treadmill walking at 5 km/hr and then during serial 2-km treadmill runs at 13 km/hr with running shoes, with and without the orthoses, and during serial 1-km runs with army boots, with and without the orthoses. RESULTS: When soft or semirigid biomechanical orthoses were worn with boots, the tibial peak-to-peak strains were significantly lowered. Soft orthoses also significantly lowered the tension and compression strain rates when worn with boots. During running, semirigid orthoses significantly increased the compression and tension strain rates when worn with boots. CONCLUSIONS: The use of biomechanical orthoses may be warranted for tibial stress fracture prevention during training in which boots are worn and that mostly involves walking, but they are not warranted for activities that primarily involve running or are performed in running shoes.     

First-time inversion ankle ligament trauma: the effects of sex, level of competition, and sport on the incidence of injury

BACKGROUND: Inversion ankle trauma is disabling, yet little is known regarding the incidence rate of first-time ankle sprains and how it is influenced by factors including sex, level of competition, and sport. HYPOTHESIS: The incidence rates of first-time ankle ligament sprains are influenced by sex, level of competition (high school vs college), and type of sports participation (basketball, soccer, lacrosse, and field hockey). STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: Between 1999 and 2003, high school and college athletes were evaluated before participation in their sports. Subjects were included in the study if they had not experienced a prior ankle or lower extremity injury and were then followed during participation in soccer, basketball, lacrosse, or field hockey to document their days of exposure to sport and injuries sustained. The relative risk associated with sex, level of competition, and sport was estimated by Cox regression. RESULTS: A total of 901 athletes had 50 680 person-days of exposure to sports, and 43 (4.8%) had an inversion injury that produced an ankle ligament sprain. Overall, the injury incidence rate was 0.85 sprains per 1000 person-days of exposure to sport. There were 0.68 and 0.97 ankle sprains per 1000 person-days of exposure to sport for the men and women, respectively. Although the risk of suffering an ankle sprain was higher for women than for men (relative risk, 1.51), the difference was not statistically significant (P = .21) and was owing to the increased risk in female basketball athletes compared to male basketball athletes (relative risk, 4.11; P = .045). Risk of injury was similar for the high school athletes in comparison to the college athletes (relative risk, 1.16). For the men, there was no difference in the risk of suffering an ankle sprain between the sports of basketball, soccer, and lacrosse, whereas for the women, the risk of suffering an ankle sprain was significantly greater during participation in basketball compared to lacrosse. CONCLUSION: In this study of first-time ankle sprains, for most sports, the incidence rate of inversion injury is less than 1 per 1000 days of exposure to sport, a value lower than previously reported. Among female athletes, ankle injury is associated with type of sport. Risk is highest for female basketball athletes, who are at significantly greater risk than male basketball athletes and female lacrosse athletes. The risk of first-time ankle injury is similar for high school and college-level athletes.     

Factors associated with discharge during marine corps basic training

This prospective study assessed risk factors for discharge from basic training (BT) among 2,137 male Marine Corps recruits between February and April 2003. Physical and demographic characteristics, exercise, and previous lower extremity injuries before arrival at Marine Corps Recruit Depot were assessed by questionnaire during intake processing. Stress fractures were confirmed by x-ray, triple-phase bone scan, or magnetic resonance imaging. Overall, 223 (10.4%) participants were discharged from training. In addition to the occurrence of a stress fracture during BT, older age (>23 years), non-Hispanic race, poor incoming self-rated physical fitness, no history of competitive exercise, and an incoming lower extremity injury with incomplete recovery were independent risk factors for discharge. Strategies to identify and allow the proper healing time for pre-BT lower extremity injuries, including interventions to improve the physical fitness of recruits before BT and reduce stress fractures during BT, may be indicated to lower attrition.     

武警某部2020年度新兵训练伤流行病学调查与分析

目的 探讨武警某部新兵军事训练伤的特点,为训练伤防控提供科学指导.方法 随机抽取武警某部2020年6个新训点4150名新兵,进行军事训练伤的发生情况问卷调查,并分析新训阶段训练伤的发生率、伤病类别等.另非随机性地选择了680名新兵进行了骨密度测定(中指骨),其中已发生训练伤340例,未发生训练伤340例.本次调查均获得...