Stress fracture
Stress fracture is a bone injury from repetitive submaximal load that outpaces bone remodeling, most often in the foot or tibia in runners, and management is dictated by the anatomic site's nonunion risk rather than by pain alone.
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What this article covers
- Overview
Stress fracture is a partial or complete bone fracture caused by repetitive submaximal mechanical loading that outpaces the bone's capacity to remodel, rather than by a single traumatic event.
- Epidemiology
Common in runners, dancers, and military recruits, populations with repetitive high-volume lower-extremity loading.
- Risk factors
Rapid increase in training volume, intensity, or activity type, the dominant precipitant across all reported populations.
- Pathophysiology
Repetitive submaximal mechanical load activates normal bone remodeling, but when the load-remodeling cycle is repeated faster than osteoblastic bone formation can keep pace, bone resorption transiently outpaces bone formation.
- Clinical features
Insidious, activity-related focal bone pain that worsens with continued weight-bearing activity and improves with rest, the hallmark pattern distinguishing stress fracture from an acute traumatic fracture.
- Differential diagnosis
Medial tibial stress syndrome (shin splints): diffuse tenderness along the anterior/medial tibia in runners without focal point tenderness, normal radiographs, and a clinical diagnosis…
- Diagnosis
Stress fracture is confirmed by imaging that demonstrates a fracture line or, when radiographs are unrevealing, by MRI showing a bone stress reaction or fracture line, in a patient with the…
- Management
First, stratify by nonunion risk using the anatomic site, since this determines whether conservative treatment alone is appropriate or specialist involvement is required.
- Complications
Nonunion, most common at the high-risk sites, leading to chronic pain and potential need for surgical fixation if not managed appropriately from the outset.
- Prognosis
Most low-risk stress fractures heal fully with conservative management, typically resuming running within 8 to 12 weeks.
- Prevention
Gradual, progressive increases in training volume, avoiding the abrupt increases (as in new military recruits) that produce clustered outbreaks; increase weekly running mileage no more than approximately 10% per week.
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