Delay in diagnosis of neck of femur stress fracture in a female military recruit

We report the delay in diagnosis of a Neck of Femur (NOF) stress fracture in mixed sex basic military training. Stress fractures are common in military training with the incidence reported as ranging between 3.2-31%. NOF stress fractures, whilst only representing around 8% of stress fractures are associated with a high morbidity. It is imperative that medical officers looking after military recruits have a sound knowledge of the potential signs, symptoms and presentation of these injuries. Medical officers should always remains vigilant for stress fractures especially in mixed military training.     

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.     

Stress fractures in athletes

Stress fractures may pose a diagnostic dilemma for radiologists since they are sometimes difficult to demonstrate on plain films and may simulate a tumour. They were first described in military personnel and professional athletes. Recently, there is an increasing incidence in the general population due to increasing sportive activities. Stress fractures occur most often in the lower extremities, especially in the tibia, the tarsal bone, the metatarsal bone, the femur and the fibula. In the upper extremities, they are commonly found in the humerus, the radius and the ulna. Some fractures of the lower extremities appear to be specific for particular sports, for example, fractures of the tibia affect mostly distance runners. Whereas stress fractures of the upper extremities are generally associated with upper limb-dominated sports. A correct diagnosis requires a careful clinical evaluation. The initial plain radiography may be normal. Further radiological evaluation could be performed by means of computerised tomography, magnetic resonance imaging and bone scanning. The latter two techniques are especially helpful for establishing a correct initial diagnosis.     

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.     

Acetabular stress fractures in military endurance athletes and recruits: incidence and MRI and scintigraphic findings

OBJECTIVE: To evaluate the incidence and the MRI and scintigraphic appearance of acetabular stress (fatigue) fractures in military endurance athletes and recruits. DESIGN AND PATIENTS: One hundred and seventy-eight active duty military endurance trainees with a history of activity-related hip pain were evaluated by both MRI and bone scan over a 2-year period. Patients in the study ranged in age from 17 to 45 years. They had hip pain related to activity and had plain radiographs of the hip and pelvis that were interpreted as normal or equivocal. The study was originally designed to evaluate the MRI and scintigraphic appearance of femoral neck stress fractures. Patients had scintigraphy and a limited MRI examination (coronal imaging only) within 48 h of the bone scan. Twelve patients demonstrated imaging findings compatible with acetabular stress fractures. RESULTS: Stress fractures are common in endurance athletes and in military populations; however, stress fracture of the acetabulum is uncommon. Twelve of 178 patients (6.7%) in our study had imaging findings consistent with acetabular stress fractures. Two patterns were identified. Seven of the 12 (58%) patients had acetabular roof stress fractures. In this group, two cases of bilateral acetabular roof stress fractures were identified, one with a synchronous tensile sided femoral neck stress fracture. The remaining five of 12 (42%) patients had anterior column stress fractures, rarely occurring in isolation, and almost always occurring with inferior pubic ramus stress fracture (4 of 5, or 80%). One case of bilateral anterior column stress fractures was identified without additional sites of injury. CONCLUSIONS: Stress fractures are commonplace in military populations, especially endurance trainees. Acetabular stress fractures are rare and therefore unrecognized, but do occur and may be a cause for activity-related hip pain in a small percentage of military endurance athletes and recruits.     

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.     

Stress fracture of the pubic ramus in a swimmer

Stress fracture is common in military recruits, joggers, and runners. Stress fracture in the pubic ramus is not common, and it constitutes only 1.25% of all stress fractures. A stress fracture, avulsion type of the pubis at the insertion of adductor magnus on an active swimmer is reported here.     

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 fracture of the tarsal navicular

Stress fractures of the lower extremity are common among military members and athletes at all levels of participation. They typically occur when an individual begins a new or different type of physical training or during periods of abrupt increase in the level of training. Stress fractures represent an incomplete remodeling of bone that occurs secondary to repetitive mechanical loading. In response to this increased loading, the osteoclastic resorption of lamellar bone outpaces the ability of the osteoblasts to create new lamellar bone, eventually leading to structural failure. The following case report reviews the typical clinical presentation, imaging findings, and treatment of the tarsal navicular stress fracture.     

The role of foot pronation in the development of femoral and tibial stress fractures: a prospective biomechanical study.

OBJECTIVE: To examine whether dynamic parameters of foot pronation are risk factors for the development of stress fractures of the femur and tibia. DESIGN: Observational prospective study. SETTING: Infantry basic training course. PARTICIPANTS: 473 recruits evaluated for stress fractures of the femur and tibia every 2 weeks during 14 weeks of infantry basic training. The final analysis included 405 recruits. ASSESSMENT OF RISK FACTORS: Two weeks before commencement of training, the recruits were evaluated during treadmill walking for their subtalar joint kinematics. Five independent variables were measured bilaterally: maximal pronation angle during the stance, pronation range of motion, time from heel strike to maximum pronation, pronation mean angular velocity, and time to maximum pronation as a percent of the total stance time. MAIN OUTCOME MEASUREMENTS: Stress fractures of the femur and tibia. These were considered positive only when proven by imaging. RESULTS: Ten percent of the participants were diagnosed with stress fractures of the femur and tibia. Recruits with longer duration of foot pronation had reduced odds ratio to develop this injury. CONCLUSIONS AND CLINICAL RELEVANCE: Longer duration of foot pronation may have a protective effect from stress fractures of the femur and tibia. This finding may promote the understanding of stress fracture pathomechanism, assist in the identification of subjects with increased risk who need augmented monitoring throughout training, and assist in future planning of impact reducing aids.     

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.     

Altered forefoot function following a military training activity

BackgroundInjury rates are high in populations that regularly undertake weight-bearing physical activity, particularly military populations. Military training activities, that often include load carriage, have been associated with lower limb injury occurrence, specifically stress fractures.Research questionRecent work identified plantar loading variables as risk factors for lower limb stress fractures in Royal Marines recruits that were assessed during barefoot running. This study aimed to quantify how those plantar loading variables changed in Royal Marines recruits following a prolonged military load carriage activity, to further understand potential mechanisms for lower limb stress fractures.MethodsBilateral, synchronised plantar pressure and lower limb kinematic data were recorded during barefoot running at 3.6 m s⁻¹ (±5%) pre- and post- a 12.8-km training activity (∼150 min). The training activity was completed with an average speed typical of walking (1.4 m.s^-1), and 35.5 kg of additional load was carried throughout. Data were collected from 32 male Royal Marines recruits who completed the training activity in week-21 of the 32-week training programme. Plantar pressure variables and ankle dorsiflexion were compared between pre- and post-activity.ResultsPost-activity there was reduced loading under the forefoot and increased loading under the rearfoot and midfoot. There was no change in dorsiflexion touchdown angle, but an increase in peak dorsiflexion and range of motion post-activity.SignificanceThe increased rearfoot loading, reduced forefoot loading and increased ankle dorsiflexion following a prolonged military load carriage activity suggest a reduced transfer of loading from the rearfoot to the forefoot during stance, which may have implications for the development of stress fractures, particularly of the metatarsals.     

Stress fractures in the lower extremity. The importance of increasing awareness amongst radiologists

Stress fractures are fatigue injuries of bone usually caused by changes in training regimen in the population of military recruits and both professional and recreational athletes. Raised levels of sporting activity in today's population and refined imaging technologies have caused a rise in reported incidence of stress fractures in the past decades, now making up more than 10% of cases in a typical sports medicine practice. Background information (including etiology, epidemiology, clinical presentation and treatment and prevention) as well as state of the art imaging of stress fractures will be discussed to increase awareness amongst radiologists, providing the tools to play an important role in diagnosis and prognosis of stress fractures. Specific fracture sites in the lower extremity will be addressed, covering the far majority of stress fracture incidence. Proper communication between treating physician, physical therapist and radiologist is needed to obtain a high index of suspicion for this easily overlooked entity. Radiographs are not reliable for detection of stress fractures and radiologists should not falsely be comforted by them, which could result in delayed diagnosis and possibly permanent consequences for the patient. Although radiographs are mandatory to rule out differentials, they should be followed through when negative, preferably by magnetic resonance imaging (MRI), as this technique has proven to be superior to bone scintigraphy. CT can be beneficial in a limited number of patients, but should not be used routinely.     

Monitoring anxiety levels and coping skills among military recruits

Military training is a very stressful life event for many recruits. It is purposefully made so in order to prepare military personnel for the long, stress-filled hours of combat. It is a time when recruits are molded into stronger, more disciplined individuals. This study investigated the stress levels and coping skills of recruits during boot camp. The Undergraduate Stress Questionnaire, State-Trait Anxiety Inventory, and the Ways of Coping Questionnaire were distributed to 48 recruits during weeks 1, 5, and 8 of training. Results of the Undergraduate Stress Questionnaire indicated that the most stressful period was week 5. This was statistically significant (p < 0.001) compared to weeks 1 and 8. Results of the State-Trait Anxiety Inventory indicated that state anxiety was highest during week 1, and was statistically significantly higher (p < 0.05) compared to weeks 5 and 8. The Ways of Coping Questionnaire indicated that problem solving was the most frequently used coping skill, followed by self control and accepting responsibility. The least used coping skill was escape/avoidance. Conclusions to be drawn from this study suggest that weeks 1 and 5 are very stressful for the recruits; however, a majority of them coped adequately with the stress by employing effective coping mechanisms. Implications include enhancing effective coping mechanisms already in place. Recruits with ineffective coping skills require anticipatory guidance and close surveillance, with possible psychiatric intervention. Replication of this study with a greater number of subjects and female recruits is indicated, as are studies that correlate physical symptoms with stress levels.     

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.     

Second metatarsal stress fracture in sport: comparative risk factors between proximal and non-proximal locations

Background

Stress fractures of the second metatarsal are common injuries in athletes and military recruits. There are two distinct areas in the second metatarsal where stress fractures develop: one proximal (at the base) and the other non‐proximal (distal). Diagnosis can be difficult, and there is a difference in prognosis and treatment of the two types of stress fracture. Therefore differentiation of fracture location is warranted. Differences in risk factors and clinical outcomes between proximal and non‐proximal stress fractures have not been studied.

Objective

To determine whether different risk factors and/or clinical outcomes associated with proximal and non‐proximal stress fractures of the second metatarsal exist.

Methods

Patients diagnosed with proximal stress fractures of the second metatarsal were included in the study. Retrospectively, an age‐matched control group with a non‐proximal stress fracture was selected for comparison. Statistical analysis involved bivariate comparisons of demographic variables and clinical measurement between the two groups.

Results

Patients with proximal stress fractures were more likely to be chronically affected, usually exhibited an Achilles contracture, showed differences in length of first compared with second metatarsal, were more likely to experience multiple stress fractures, and exhibited low bone mass. In addition, a high degree of training slightly increased the risk of a non‐proximal fracture, whereas low training volume was associated with a proximal stress fracture.

Conclusion

The signs, symptoms and clinical findings associated with proximal metatarsal stress fractures are different from those of non‐proximal stress fractures.     

"March fractures" on a female military recruit

Stress fractures are caused by repetitive low-impact activities. It is important to have a high index of suspicion in diagnosing and treating stress fractures early for remodeling to occur. This is a case report of a 19-year-old female military recruit with stress fractures of the right foot. The patient had an extended non-weight-bearing treatment that eventually had a successful outcome after allowing the fracture to heal by starting the patient on weight-bearing activities and a "walk-to-run" program. Treatment points in managing stress fractures including female-specific issues are also discussed.     

Using bone's adaptation ability to lower the incidence of stress fractures

In three prospective epidemiologic studies of the effect of pre-military-induction sport activities on the incidence of lower extremity stress fractures during infantry basic training, recruits who played ball sports (principally basketball) regularly for at least 2 years before basic training had a significantly lower incidence of stress fractures (13.2%, 16.7%, and 3.6% in the three studies, respectively) than recruits who did not play ball sports (28.9%, 27%, and 18.8%, respectively). Preinduction running was not related to the incidence of stress fracture. To assess the tibial strain environment during these sport activities, we made in vivo strain measurements on three male volunteers from the research team. Peak tibial compression and tension strain and strain rates during basketball reached levels 2 to 5.5 times higher than during walking and about 10% to 50% higher than during running. The high bone strain and strain rates that occurred in recruits while playing basketball in the years before military induction may have increased their bone stiffness, according to Wolff's Law. The stiffer bone could tolerate higher stresses better, resulting in lower strains for a given activity and a lower incidence of stress fractures during basic training.     

Physical and psychological stressors linked with stress fractures in recruit training

This study aimed to measure ambulation in infantry army basic training, and to evaluate if covering more distance can explain stress fractures in a stressor–stress model. Forty‐four male combat recruits (18.7 ± 0.7 years) participated in a 6‐month rigorous high intensity combat training program. Baseline data included anthropometric measurements, VO₂max, and psychological questionnaires. Actual distance covered was measured using a pedometer over an 11‐week training period. Psychological questionnaires were repeated after 2 months. Sixteen recruits were diagnosed with stress fractures by imaging (SFi = 36.4%). Statistical analysis included comparing measured variables between SFi and those without stress fractures (NSF). The recruits covered 796 ± 157 km, twofold the distance planned of 378 km (P < 0.001). The SFi group covered a distance 16.4% greater than that of the NSF group (866 ± 136 and 744 ± 161 km, respectively, P < 0.01), and also demonstrated greater psychological stress. These data reveal the importance of adherence to or enforcement of military training programs. In the light of these data, the Israeli Defense Forces program needs reappraisal. A stressor–stress response might explain the susceptibility of certain recruits for injury. Using advanced technology, monitoring ambulation may prevent stress fracture development by limiting subjects exceeding a certain level. Psychological profile may also play a role in predicting stress fracture development.     

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.