Joseph Wall, MDa*, John F. Feller, MDb ib aDesert Valley Radiology, 4045 E. Bell Road, Suite 143, Phoenix, AZ 85032, USA bDesert Medical Imaging, 74-785 Highway 111, Suite 101, Indian Wells, CA 92210, USA
Running is an extremely popular form of exercise. The emphasis today on the importance of exercise and weight loss and the convenience and low cost of running as a form of exercise have undoubtedly led to this popularity. Running-related injuries are common, however, and the current focus on the importance of health, diet, and fitness as well as competitive athletics has resulted in many individuals undertaking new or increasing levels of physical activity. This results in increasing levels of stress on the musculoskeletal system. Stress fractures in runners are a common problem, but the diagnosis and treatment is often challenging. Health care providers caring for recreational and professional athletes must be knowledgeable of the signs and symptoms of these injuries and maintain a high suspicion when seeing active patients seeking care for lower extremity and axial skeletal pain, because the signs and symptoms are often vague and overlap with other diagnoses.
There is a spectrum of osseous stress injuries that occurs, beginning with stress reaction or stress response and eventually leading to stress fracture. The path-ophysiology of stress reaction and stress fractures is related to the bone response to the repetitive stresses at the cellular level. With excess stresses, the osteoclasts replace the circumferential lamellar bone with dense osteonal bone. This is accompanied by the development of edema and hyperemia, which is the stress reaction or stress response that can be demonstrated by MRI. The relative muscle groups, which are also experiencing the repetitive stresses, respond with hypertrophy and strengthening more rapidly than bone, and this force is transmitted to the periosteum at the muscle attachments, resulting in periostitis. Stress fractures are microfractures of bone that result from repetitive physical loading of the involved bone, which can lead to complete fractures if the excessive stress on the bone continues [1,2].
Stress fractures fall into two general categories: fatigue stress fractures and insufficiency fractures. Fatigue stress fractures result from the exposure of
*Corresponding author. E-mail address: [email protected] (J. Wall).
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