Stress fracture
Overview
There are two types of stress fracture:
- Fatigue fracture: Repetitive (normal) stress/overused on normal bone
- Insufficiency fracture: Repetitive (minimal) stress on weakened bone
Management triage is risk-based:
- Low-risk: Conservative management
- High-risk: May require urgent fixation (risk of non-union/complications)
High risk stress fractures
- Tensile side and/or poor blood supply (e.g., navicular, anterior tibia)
- Most are fatigue fractures, but Atypical femoral fracture is a uniquely high-risk insufficiency fracture
| Location | Classic Patient | Notes |
|---|---|---|
| Tibia (anterior cortex, mid shaft) | Runners, military | - Poor blood supply; see Fredericson classification grades for medial tibial stress syndrome.png |
| Femoral neck (tension side) | Runners | Can displace → urgent referral |
| Medial malleolus | Runners, skaters | Vertical fracture pattern |
| Navicular | Jumpers | Poor blood supply; risk of AVN |
| Sesamoid (great toe) | Dancers, runners | Plantarflexion stress |
| Talus | Jumpers, runners | |
| 5th metatarsal (proximal diaphyseal) | Football, basketball | Only the Jones fracture zone is high-risk (poor blood supply) |
Low risk stress fractures
- Compressive side
- Usually heal conservatively
| Location | Classic Patient | Notes |
|---|---|---|
| Fatigue fracture | ||
| Calcaneus (posterosuperior) | Runners | Often bilateral |
| Metatarsals (esp. 2nd and 3rd shafts) | Ballet dancers, runners | "March fracture", often 2nd MT |
| Posteromedial tibia (distal) | Runners | |
| Fibula (distal 1/3) | Track athletes | |
| Femoral neck (compressive side) | Runners | can still displace if not offloaded |
| Patella (longitudinal) | Jumpers | low-risk if not displaced |
| Insufficiency fracture | elderly, postmenopausal female, steroids, RA | |
| Sacrum | Bone scan = Honda sign | |
| Pubic rami | Often coexists with sacral stress fx | |
| Vertebral body |
Imaging approach #PracitcalPoints
- Clinical suspicion (pain with activity, overuse history, point tenderness)
- X-ray (first-line)
- Often normal early
- Classic findings (if present): linear sclerosis, cortical break, periosteal reaction
- If X-ray negative, but suspicion remains high:
- MRI (gold standard)
- Most sensitive for early detection (marrow edema, before cortical change)
- Differentiates from tumor, infection, etc.
- Bone scan (if MRI not available/contraindicated)
- Highly sensitive but not specific
- Follow up
- Repeat X-ray in 2-3 weeks if MRI is not done.
- MRI (gold standard)
Pearls
- Image contralateral limb for subtle/uncertain cases (especially navicular, femoral neck).
- CT: for surgical planning, occult cortical detail, or if MRI non-diagnostic
Differential diagnosis #ddx
| Dx | Classic Patient | Imaging Features | Key Clues / Differentiators |
|---|---|---|---|
| Fatigue fracture | Young athlete, overuse | Linear sclerosis, periosteal reaction, MRI: low T1, high T2/STIR | Risk site, hx, activity |
| Pathologic fx | Elderly, cancer hx | Lytic/blastic lesion, abnormal bone | Underlying lesion, “no trauma” |
| Periostitis | Runners, repetitive use | Periosteal elevation, no fracture line | Fusiform thickening, no fx |
| Osteoid osteoma | Young, night pain | Lucent nidus, reactive sclerosis | NSAID relief, classic x-ray |
| Osteomyelitis | Sickle cell, diabetics | Lytic lesion, periosteal reaction, marrow edema | Systemic symptoms, infection labs |
Red flag symptoms #PracitcalPoints
- Persistent pain at rest or at night (not relieved by rest)
- Pain that increases despite decreased activity/off-loading
- Localized swelling, warmth, or erythema
- New or worsening limp / inability to bear weight
- History of trauma with disproportionate pain
- Failure to improve with conservative management after 2–3 weeks
- Systemic symptoms (fever, malaise) → consider infection or malignancy
If any of these are present, recommend MRI or specialist referral to exclude high-risk fracture, pathologic fracture, infection, or malignancy.
