Epidemiology

Etiology

Population: Military recruits, competitive runners, ballet dancers, gymnasts.
Mechanisms & Triggers:
- Abrupt ↑ in training volume, frequency, or intensity without adequate recovery.
- Repetitive mechanical overload exceeding bone remodeling capacity.
Common Sites:
- 2nd and 3rd metatarsal shafts (most common overall; “march fracture”).
- Posteromedial tibial shaft (most common lower leg). c
- Fibula, calcaneus, navicular, femoral neck.
Risk Factors:
- Female Athlete Triad: Low energy availability/eating disorder, amenorrhea/oligomenorrhea, ↓ BMD (osteopenia/osteoporosis).
- Nutritional deficiencies: Low Vit D, inadequate Ca intake, anorexia nervosa
  - Consider these if happens in male c
- Biomechanical abnormalities: Cavus feet (high arch), leg-length discrepancy.

Tip

The female athlete triad syndrome is associated with an increased risk of stress fractures.

History:
- Insidious onset of localized, aching pain.
- Initially occurs only with weight-bearing or end of training session; relieved by rest.
- Progresses to pain during daily ambulation, and eventually rest/night pain.
Physical Exam:
- Focal point tenderness directly over the affected bone cortex (hallmark). c
- Localized soft tissue edema and erythema.
- Positive “tuning fork” or percussion test (vibration reproduces sharp, localized pain).
- Antalgic gait.

X-ray: recommended initial imaging study
- Radiographic features of stress fractures include:
  - Fracture line: line of faint lucency
  - Indirect features: periosteal thickening, increased cortical density, formation of a callus, endosteal thickening and/or sclerosis
- Often normal in the first 2–3 weeks of disease onset

Medial Tibial Stress Syndrome (“Shin Splints”):
- Diff by diffuse tenderness along posteromedial tibial border (>5 cm) without focal point tenderness; XR normal; MRI shows periosteal edema without cortical line or deep marrow edema.

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tags	—
aliases	Stress fracture