Suspected stress or insufficiency fracture

ACR AC Stress (Fatigue/Insufficiency) Fracture (2024 rev)

Radiographs first — cheap, quick and occasionally diagnostic — then MRI of the symptomatic region when they are normal and the clinical suspicion persists. The site does more work than the modality: high-risk locations change management even when the fracture is barely visible.

Activity-related bone pain in a runner, military recruit or dancer, or an insufficiency fracture in an older patient with osteoporosis, previous pelvic radiotherapy or long-term corticosteroids.

Referenced decision support — confirm against your local protocol.

Decision support, not a directive. Protocols and timings shown are typical published ones — your local protocol takes precedence, and the vetting radiologist decides.

The request in front of you

Everything is optional. Leave a field alone and the answer assumes nothing — the verdict updates as you go.

Study requested

What the referrer actually asked for. It is evidence of intent, not a constraint on the right answer.

Contrast as written

What the request form says, not what it should say.

Age

Pick a band, or type an exact age if it matters.

years

Pregnancy status

Renal risk factors

The question a vetter can actually answer from the request. An explicit “none known” is a real answer, and it removes checks rather than deferring them.

Previous contrast reaction

The pathway — tap anything already done

Marking a study complete moves the answer on. A patient arrives partway through a pathway far more often than at the start of one.

Accept as requested

Limb radiograph — two orthogonal views

Limb radiograph

What we'd amend, and why

Radiography is the baseline study: when it shows a periosteal reaction, a cortical lucency or the dense sclerotic band of a healing insufficiency fracture, the pathway ends there. It also detects the alternative diagnoses that matter most — an aggressive bone lesion presenting as activity-related pain is uncommon but must not be assumed away.

Nothing needs resolving before this goes ahead. Routine checks below are owned downstream.

How was this decided?

pathwayany — All patients
rulerule-paeds-dose — Child-sized technique and contrast dose; checked by Radiographer at the scanner

Decision support only. Local protocol takes precedence.

Handled at the scanner(1)nothing for you to do

Settled and owned downstream. Each returns to a radiologist only on the stated trigger.

Child-sized technique and contrast dose
Confirm that a size- or weight-based protocol is selected — child-sized kV and mAs against size-based diagnostic reference ranges — and that contrast volume is calculated by weight rather than taken from an adult default. Weight-based iodinated contrast volumes of roughly 1.5–2.0 mL/kg are widely used in paediatric CT.
Radiographer at the scannerAt the scanner
Flags back if: No paediatric or size-based protocol exists on the scanner for the requested examination, or the requested coverage or number of phases exceeds what the clinical question needs — for example a multiphase study where a single phase answers it, or whole-body coverage for a focal question.

Worth asking the referrer (1)

None of these hold the request up. They sharpen the protocol or the plan that follows.

Exactly where is the pain, and what activity brought it on?
The site determines both which region is imaged and whether the fracture is high-risk; a limb-wide request produces a study that images the wrong bone.

Pathways

Big forks are separate pathways; the first whose conditions match is the one used.

All patients

Matches your inputsDefault

Role	Study & protocol	Why this answers the question
First line	Limb radiograph Limb radiograph — two orthogonal views usually appropriate	Radiography is the baseline study: when it shows a periosteal reaction, a cortical lucency or the dense sclerotic band of a healing insufficiency fracture, the pathway ends there. It also detects the alternative diagnoses that matter most — an aggressive bone lesion presenting as activity-related pain is uncommon but must not be assumed away.
Second line	MRI Hip MRI Hip — routine	For pain in the hip, groin, pelvis or sacrum with normal radiographs, a large field-of-view MRI covering both hips, the rami and the sacrum is the next study: it grades the injury from marrow oedema through to a true fracture line, and it distinguishes a compression-side femoral neck stress fracture that can be managed conservatively from a tension-side one that needs fixation. Intravenous contrast adds nothing to this question.
Second line	MRI Ankle and Hindfoot MRI Ankle and Hindfoot — routine	The equivalent study for the lower leg, ankle and foot, which is where most fatigue fractures occur. It separates a stress reaction from a fracture line, and it identifies the navicular and anterior tibial cortex injuries whose management differs sharply from a routine metatarsal stress fracture.
Reasonable alternative	Bone scintigraphy Bone scintigraphy — whole body (± three phase)	Highly sensitive and useful when the site is genuinely unlocalised or MRI is contraindicated, but it is non-specific: degenerative change, infection and tumour all take up tracer, and the anatomical detail that decides management is absent.

Pitfalls

Reading a normal early radiograph as excluding a stress fracture, and returning the athlete to training.
Requesting a whole-limb MRI when the symptoms are focal, which dilutes the resolution over the area that mattered.
Not distinguishing tension-side from compression-side femoral neck injury; only one of them is safe to mobilise.
Interpreting sacral insufficiency fracture oedema as metastatic disease in an older patient, or the reverse — an insufficiency fracture through a metastasis is a real and easily missed combination.
Ignoring an atypical subtrochanteric or diaphyseal femoral lucency in a patient on long-term bisphosphonates.

Priors — what to pull first

Previous imaging of the same site distinguishes a healing old injury from a new one — a sclerotic band with no oedema is old.
A history of previous stress fractures, or of pelvic radiotherapy, reframes the whole study.

What makes a good request

High-risk sites — the tension side of the femoral neck, the anterior tibial cortex, the tarsal navicular, the base of the second metatarsal and the sacrum — behave differently from low-risk ones and often mean non-weight-bearing or surgery, so naming the site on the request changes what is done with the result.
Radiographs are frequently normal for the first weeks; a normal film early is expected, not reassuring.
In a young athlete with recurrent stress fractures, the underlying question is often nutritional and hormonal rather than radiological, and the report is a good place to say so.

How these studies are acquired

Contrast, phases and timing for every study on the pathways above.

Limb radiograph — two orthogonal views MRI Hip — routine MRI Ankle and Hindfoot — routine Bone scintigraphy — whole body (± three phase)

Confirm locally

Timings, contrast volumes and rates above are typical published values. Your department's protocol, scanner and patient population decide the actual numbers.
Safety thresholds and premedication policy follow local policy where it differs from the cited guidance.

References

Implemented from the cited published sources. Educational and workflow support only; confirm against current guidelines and local policy before clinical use.