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Textbook/Clinical imaging and interpretation/Occult fracture and when to escalate imaging
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Occult fracture and when to escalate imaging

Recognise when normal initial radiographs leave clinically important fracture risk unresolved, choose MRI or CT for the suspected structure, and provide protection and follow-up meanwhile.

24 min full readUK scopeSources checked 13 Sept 2026Clinical review pending
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Negative radiography does not neutralise danger

Inability to bear weight, high-energy injury, neurovascular change, threatened skin or suspected hip fracture remains urgent despite an apparently normal film.

Action: Reassess, protect from further injury, involve the appropriate senior team and obtain definitive imaging without unsafe discharge or repeated low-yield delay.

Open the sections you need. The overview is shown first.
01Purpose and principlesWhat the assessment is for and the core concepts behind it.

Radiographic occultness is a property of timing, anatomy and technique rather than proof that no fracture exists. Nondisplaced lines aligned with the beam, trabecular impaction, unossified cartilage and crowded anatomy may be invisible. Early stress or insufficiency injury can produce marrow change before cortical or periosteal signs. The pre-test probability therefore comes from mechanism, focal tenderness, function and vulnerability as well as the film.

Escalation begins with a technical check. Wrong centring, missing orthogonal views or absent special projections may justify repeat or additional radiography immediately. When adequate radiographs remain negative, the next modality depends on the question. MRI is highly sensitive to marrow oedema and detects associated ligament or cartilage damage; CT provides rapid high-resolution cortical anatomy and is valuable for complex regions or when MRI cannot be performed.

The pathway must include interim treatment. Suspected fracture should be protected from displacement or repeated loading, with analgesia and explicit instructions. A planned scan is not safe unless someone is responsible for checking it and acting on it. If symptoms intensify or neurovascular findings change, urgency is reset by the patient rather than the scheduled appointment.

Key points

  • An occult fracture is clinically suspected but not visible or confidently diagnosable on the initial radiographic examination.
  • First confirm that the correct region, adequate orthogonal views and any appropriate targeted projection were obtained and reviewed against maximal tenderness.
  • NICE advises considering MRI first line after thorough examination for suspected scaphoid fracture rather than assuming normal radiographs exclude it.
  • For suspected hip fracture despite adequate negative radiographs, offer MRI; if MRI is unavailable within 24 hours or contraindicated, consider CT.
  • MRI detects marrow and trabecular injury and related soft-tissue damage, whereas CT excels at cortical detail and complex fracture geometry but can miss subtle marrow injury.
  • Protect the suspected injury, restrict use or weight bearing as appropriate, provide analgesia and make a named plan for imaging, result review and reassessment.
02Indications, selection and cautionsWhen it is useful, when urgency changes and important limitations.
Focal bony tenderness

Point tenderness over a vulnerable bone or physis after a compatible mechanism sustains fracture probability even when the first image looks normal.

Functional failure

Inability to bear weight, use the limb or perform a previously possible action can be a stronger warning than minimal swelling or a subtle film.

Scaphoid pattern

Snuffbox tenderness, scaphoid-tubercle tenderness and pain with axial thumb loading justify a dedicated occult-fracture pathway rather than reassurance.

Occult hip patternRed flag

Groin pain, pain on axial loading or rotation and inability to mobilise after a fall should trigger further imaging despite adequate negative radiographs.

Stress injury

Activity-related focal pain may precede any radiographic fracture line; high-risk sites or continued loading increase the need for early MRI and protection.

Paediatric physis

A normal radiograph may not show a Salter-Harris I injury because the physis is cartilaginous; examination and follow-up remain decisive.

Red flags requiring action

  • An older person unable to bear weight after a fall needs an occult hip-fracture pathway even when adequate hip radiographs are negative.
  • Persistent anatomical snuffbox or scaphoid-tubercle tenderness can represent a scaphoid fracture with later nonunion or avascular necrosis risk.
  • Pain out of proportion, worsening swelling or new neurological or perfusion abnormality requires immediate clinical review rather than simply another image.
  • Children may have radiographically occult physeal, cartilaginous or buckle injury; focal examination findings and developmental anatomy must guide protection.
03Method and interpretationA systematic approach to the test and its findings.
Investigation order

Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.

  1. 01
    Repeat targeted radiographsFirst step
    Why
    Correct missing coverage or projection and demonstrate interval sclerosis, callus or displacement.
    Interpretation and limitations
    Repeating an already adequate study immediately has low yield; delay is acceptable only when the injury is protected and follow-up is reliable.
  2. 02
    Magnetic resonance imaging
    Why
    Identify marrow oedema, trabecular fracture and concurrent cartilage, ligament or tendon injury.
    Interpretation and limitations
    MRI is preferred in NICE occult hip and suspected scaphoid pathways, but urgent access, contraindications and the exact anatomy affect delivery.
  3. 03
    Computed tomography
    Why
    Show cortical breaks and three-dimensional configuration rapidly in complex or overlapping anatomy.
    Interpretation and limitations
    A negative CT may not end strong suspicion of trabecular hip or stress injury; MRI or specialist review can still be required.
  4. 04
    Ultrasound
    Why
    Assess selected superficial cortical or paediatric injuries and related effusion where expertise exists.
    Interpretation and limitations
    Operator dependence and limited marrow assessment prevent ultrasound from serving as a universal fracture-exclusion test.
  5. 05
    Bone scintigraphy
    Why
    Detect increased bone turnover when MRI is unavailable for selected multifocal or delayed questions.
    Interpretation and limitations
    Lower spatial specificity, radiation and delayed positivity make it a secondary option rather than the routine acute solution.
04Clinical next stepsHow the result changes management or prompts escalation.
01Hip pathwayPersist after negative hip filmsFirst stepAn adult remains unable to bear weight with suspected hip fracture after adequate normal radiographs.
  1. 1Maintain analgesia and safe transfer while treating the hip as fractured until the question is resolved.
  2. 2Offer MRI and arrange it within the urgent pathway; if unavailable within 24 hours or contraindicated, consider CT.
  3. 3If CT is negative but clinical concern persists, obtain senior radiology and orthopaedic review and consider MRI.
  4. 4Assign ownership for the result, mobilisation decision and prevention of complications from immobility.
02Scaphoid pathwayProtect the clinically suspicious wristExamination suggests scaphoid injury even though initial radiographs are negative or equivocal.
  1. 1Document the precise tenderness pattern and obtain appropriate wrist and scaphoid projections if not already completed.
  2. 2DefinitiveImmobilise according to the local pathway and explain why a normal first film is not definitive.
  3. 3First lineConsider first-line MRI after thorough clinical examination as advised by NICE NG38.
  4. 4Ensure a named clinician reviews imaging and releases or continues protection based on both result and symptoms.
03ReassessmentEscalate unresolved focal painEscalationPain or loss of function persists after an apparently reassuring initial study.
  1. 1Repeat history and examination, including exact tenderness, loading ability and new neurovascular or skin findings.
  2. 2Verify the anatomical coverage and seek experienced image review for subtle indirect signs.
  3. 3Choose MRI for marrow-predominant or soft-tissue-associated injury and CT for detailed cortical geometry.
  4. 4Provide interim protection and a timed review rather than open-ended reassurance or serial films without a decision point.
05Risks, monitoring and follow-upComplications, safety checks and further assessment.
  • Record the date, modality and responsible reviewer for all planned occult-fracture imaging.
  • Recheck pain, focal tenderness, function and distal neurovascular status at the arranged clinical review.
  • Confirm that immobilisation remains safe, fits correctly and has not produced pressure or neurological symptoms.
  • After a negative advanced study, reconsider an alternative diagnosis if symptoms remain discordant rather than repeating reassurance.
  • For stress or insufficiency injury, monitor graded return to load and address relevant training, nutrition or bone-health factors.
06Special situationsVariants, exceptions and circumstances that change the usual approach.

Adequate matters

The occult hip recommendation applies after hip radiographs of adequate standard, so a poor study first needs technical correction.

CT and MRI differ

CT depicts cortex and fracture geometry rapidly; MRI is more sensitive to marrow injury and associated soft-tissue pathology.

Time can reveal

Healing response may make some fractures visible later, but planned delayed radiography is safe only with protection and reliable review.

Children are different

Unossified epiphyses and physes require knowledge of developmental anatomy, and comparison should be used selectively under expert guidance.

Stress location changes urgency

Femoral-neck, navicular and anterior tibial stress injuries have greater displacement or nonunion consequences than many low-risk sites.

A result needs an owner

The most sophisticated scan does not prevent harm if nobody receives it, correlates it with the patient and changes the plan.

07Common pitfallsFrequent interpretation and management errors.
  1. 01

    Declaring no fracture from an inadequate or single-view series.

  2. 02

    Letting a negative CT override persistent occult hip-fracture features without review.

  3. 03

    Sending a suspicious scaphoid injury away unprotected with no defined imaging plan.

  4. 04

    Using ultrasound as a general substitute for marrow-sensitive imaging.

  5. 05

    Scheduling follow-up without naming who will review and act on the result.

Practice

Two practice questions

Question 1 of 20 correct
Clinical imaging and interpretationOriginal SBA

Occult hip imaging

An 82-year-old remains unable to bear weight with groin pain after a fall, but adequate AP pelvis and lateral hip radiographs show no fracture. What should happen next?

Sources and review status3 sources · checked 13 Sept 2026 · clinical review pending
Sources

Sources and review status

National guidance is shown before implementation-dependent detail. Apply principles in context and verify current guidance when a decision affects care. Source check completed 13 Sept 2026; clinical approval remains outstanding.

Authoring stateComplete draftClinical stateAwaiting reviewJurisdictionUnited Kingdom