The radiograph is normal early; MRI grades the injury from periosteal oedema to a fracture line — and the high-risk sites (femoral neck tension side, anterior tibial cortex, navicular, fifth metatarsal base) need a different plan.
Orient first
- Fatigue fractures: abnormal load on normal bone (athletes, recruits); insufficiency: normal load on abnormal bone (osteoporosis, radiotherapy).
- Fredericson (tibia) or similar MRI grading predicts return to activity (verify scheme).
- Sacral and pelvic insufficiency fractures in the elderly are commonly missed.
Acquire the study
- Two views; repeat after 10–14 days if normal and suspicion remains.
The manoeuvre
- Radiograph: periosteal reaction or a sclerotic band.
- Dreaded black line: anterior tibial cortex (high risk).
- Femoral neck: sclerosis on the compression (medial) vs tension (lateral) side.
What confirms it
- Marrow oedema with a fracture line in a compatible site and history.
What licenses you to exclude it
- A normal MRI excludes a stress injury.
The classic misread
- A normal early radiograph reassuring.