Stress Fractures: Etiology, Epidemiology, Diagnosis, Treatment, and Prevention.

Stress fractures are part of a continuum of changes in healthy bones in response to repeated mechanical deformation from physical activity. If the activity produces excessive repetitive stress, osteoclastic processes in the bone may proceed at a faster pace than osteoblastic processes, thus weakening the bone and augmenting susceptibility to stress fractures. Overall stress fracture incidence is about three cases per 1,000 in active duty Servicemembers, but it is much higher among Army basic trainees: 19 per 1,000 for men and 80 per 1,000 for women. Well-documented risk factors include female sex, white ethnicity, older age, taller stature, lower aerobic fitness, prior physical inactivity, greater amounts of current physical training, thinner bones, cigarette smoking, and inadequate intake of vitamin D and/or calcium. Individuals with stress fractures present with focal tenderness and local pain that is aggravated by physical activity and reduced by rest. A sudden increase in the volume of physical activity along with other risk factors is often reported. Simple clinical tests can assist in diagnosis, but more definitive imaging tests will eventually need to be conducted if a stress fracture is suspected. Plain radiographs are recommended as the initial imaging test, but magnetic resonance imaging has higher sensitivity and is more likely to detect the injury sooner. Treatment involves first determining if the stress fracture is of higher or lower risk; these are distinguished by anatomical location and whether the bone is loaded in tension (high risk) or compression (lower risk). Lowerrisk stress fractures can be initially treated by reducing loading on the injured bone through a reduction in activity or by substituting other activities. Higher-risk stress fractures should be referred to an orthopedist. Investigated prevention strategies include modifications to physical training programs, use of shock absorbing insoles, vitamin D and calcium supplementation, modifications of military equipment, and leadership education with injury surveillance.

Load Carriage-Related Paresthesias (Part 2): Meralgia Paresthetica.

This is the second of a two-part series addressing symptoms, evaluation, and treatment of load carriage- related paresthesias. Part 1 addressed rucksack palsy and digitalgia paresthetica; here, meralgia paresthetica (MP) is discussed. MP is a mononeuropathy involving the lateral femoral cutaneous nerve (LFCN). MP has been reported in load carriage situations where the LFCN was compressed by rucksack hipbelts, pistol belts, parachute harnesses, and body armor. In the US military, the rate of MP is 6.2 cases/10,000 personyears. Military Servicewomen have higher rates than Servicemen, and rates increase with age, longer loadcarriage distance or duration, and higher body mass index. Patients typically present with pain, itching, and paresthesia on the anterolateral aspect of the thigh. There are no motor impairments or muscle weakness, because the LFCN is entirely sensory. Symptoms may be present on standing and/or walking, and may be relieved by adopting other postures. Clinical tests to evaluate MP include the pelvic compression test, the femoral nerve neurodynamic test, and nerve blocks using lidocaine or procaine. In cases where these clinical tests do not confirm the diagnosis, specialized tests might be considered, including somatosensory evoked potentials, sensory nerve conduction studies, high-resolution ultrasound, and magnetic resonance imaging. Treatment should initially be conservative. Options include identifying and removing the compression if it is external, nonsteroidal inflammatory medication, manual therapy, and/or topical treatment with capsaicin cream. Treatments for intractable cases include injection of corticosteroids or local anesthetics, pulsed radiofrequency, electroacupuncture, and surgery. Military medical care providers may see cases of MP, especially if they are involved with units that perform regular operations involving load carriage.

Injury and illness incidence in a Sergeants Major Academy class.

PURPOSE: This study examined the incidence and risk factors for training injuries and illnesses for 149 male and 6 female U.S. Army Sergeants Major Academy students. METHODS: This was a retrospective report based on injuries and illnesses that occurred during 9.5 months of physical fitness training including running, marching, and calisthenics. During this time, 49.7% (74/149) students were injured at least once. The crude incidence rate was 5.2 injuries (68.9%), and accounted for 1749 limited duty days (LDD). The most common overuse injuries were pain, muscle strain, and tendinitis/bursitis involving primarily the lower extremities and lower back. For illnesses, 63.1% (94/149) of the students had one or more illness visits to a medical facility. The crude incidence rate was 6.6 illnesses per 100 soldiers per month. Infectious illnesses were the most frequent illness reported (48.3%), and 94 students had a total of 311 days of illness-associated LDD. CONCLUSIONS: Medical record reviews revealed that musculoskeletal injuries were the major cause of LDD during physical fitness training. Overuse lower extremity and lower back injuries were the most commonly reported injuries. Respiratory bacterial and viral infectious illnesses were the most commonly reported illnesses. Alcohol consumption was a risk factor for developing infectious illnesses. Cigarette smoking was associated with slower 2-mile run times when compared with history of nonsmoking.