Mateusz Gładysz FESSH prep

FESSH prep Imaging Prevalence of true fracture, diagnostic accuracy of CT, MRI and bone scintigraphy, the absent reference standard, NICE NG38, displacement on CT

Imaging of the clinically suspected scaphoid fracture

Last reviewed v1.0

FESSH-054Imaging●●○ intermediate

Regarding imaging of a clinically suspected scaphoid fracture with normal initial radiographs:

  1. 1.Most patients with a clinically suspected scaphoid fracture and normal initial radiographs are later shown to have a scaphoid fracture.

  2. 2.Radiographs repeated at six weeks provide a reliable reference standard for a suspected scaphoid fracture, with high agreement between observers.

  3. 3.When MRI is performed for a suspected scaphoid fracture with normal initial radiographs, it frequently shows fractures of other bones, such as the distal radius, and changes management in most patients.

  4. 4.UK guidance on non-complex fractures (NICE NG38) advises considering MRI as first-line imaging for a suspected scaphoid fracture after a thorough clinical examination.

  5. 5.Plain radiographs tend to underestimate displacement of a scaphoid fracture compared with CT.

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Question ID
FESSH-054
First published
Last reviewed
Version
v1.0
Answer key and explanations — open after answering

  1. 1. Most patients with a clinically suspected scaphoid fracture and normal initial radiographs are later shown to have a scaphoid fracture.

    False

    True fractures are a minority of suspected fractures: a 2023 systematic review found a prevalence of 9.0%, the Cochrane diagnostic review reports a median prevalence of about 20%, and Bäcker's meta-analysis reported an overall incidence of 21.8% for scaphoid fractures missed on radiographs and diagnosed on advanced imaging. The low prevalence makes the lower specificity of bone scintigraphy a practical problem.

    • Mallee WH, Wang J, Poolman RW, Kloen P, Maas M, de Vet HCW, et al.. Computed tomography versus magnetic resonance imaging versus bone scintigraphy for clinically suspected scaphoid fractures in patients with negative plain radiographs. Cochrane Database Syst Rev. 2015;2015(6):CD010023. PMID 26045406
    • Bäcker HC, Wu CH, Strauch RJ. Systematic Review of Diagnosis of Clinically Suspected Scaphoid Fractures. J Wrist Surg. 2019;9(1):81-89. PMID 32025360
    • Coventry L, Oldrini I, Dean B, Novak A, Duckworth A, Metcalfe D. Which clinical features best predict occult scaphoid fractures? A systematic review of diagnostic test accuracy studies. Emerg Med J. 2023;40(8):576-582. PMID 37169546

  2. 2. Radiographs repeated at six weeks provide a reliable reference standard for a suspected scaphoid fracture, with high agreement between observers.

    False

    In Mallee's study, 81 orthopaedic surgeons assessed initial and six-week scaphoid radiographs of 34 patients, with CT and MRI as the reference: interobserver agreement was only slight (kappa 0.15 and 0.14) and diagnostic performance poor, so six-week radiographs were judged not adequate for evaluating suspected scaphoid fractures. Stirling's review notes that there is no consensus reference standard for a true fracture, which complicates every accuracy study.

    • Mallee WH, Mellema JJ, Guitton TG, Goslings JC, Ring D, Doornberg JN, et al.. 6-week radiographs unsuitable for diagnosis of suspected scaphoid fractures. Arch Orthop Trauma Surg. 2016;136(6):771-8. PMID 27026536
    • Stirling PHC, Strelzow JA, Doornberg JN, White TO, McQueen MM, Duckworth AD. Diagnosis of Suspected Scaphoid Fractures. JBJS Rev. 2021;9(12). PMID 34879033

  3. 3. When MRI is performed for a suspected scaphoid fracture with normal initial radiographs, it frequently shows fractures of other bones, such as the distal radius, and changes management in most patients.

    True

    In Brydie's 195 patients scanned within 14 days, MRI showed 37 scaphoid fractures (19%), 28 distal radius fractures (14%) and 9 fractures of other carpal bones (5%); management changed in 92%. Occult fractures were present in almost two-fifths, half of them in the scaphoid. In Tibrewal's series MRI diagnosed fractures in 22.0% of examinations and bone marrow oedema without a distinct fracture in 40.4%.

    • Brydie A, Raby N. Early MRI in the management of clinical scaphoid fracture. Br J Radiol. 2003;76(905):296-300. PMID 12763944
    • Tibrewal S, Jayakumar P, Vaidya S, Ang SC. Role of MRI in the diagnosis and management of patients with clinical scaphoid fracture. Int Orthop. 2011;36(1):107-10. PMID 21898036

  4. 4. UK guidance on non-complex fractures (NICE NG38) advises considering MRI as first-line imaging for a suspected scaphoid fracture after a thorough clinical examination.

    True

    Recommendation 1.2.3 of NICE NG38 (2016) reads: consider MRI for first-line imaging in people with suspected scaphoid fractures following a thorough clinical examination. It is a 'consider' recommendation rather than a firm one. A pragmatic randomised trial in a London emergency department later found immediate MRI cheaper than standard care with radiographs only, with more quality-adjusted life years.

    • National Institute for Health and Care Excellence. Fractures (non-complex): assessment and management. NICE guideline NG38. National Institute for Health and Care Excellence. 2016.
    • Rua T, Gidwani S, Malhotra B, Vijayanathan S, Hunter L, Peacock J, et al.. Cost-Effectiveness of Immediate Magnetic Resonance Imaging In the Management of Patients With Suspected Scaphoid Fracture: Results From a Randomized Clinical Trial. Value Health. 2020;23(11):1444-1452. PMID 33127015

  5. 5. Plain radiographs tend to underestimate displacement of a scaphoid fracture compared with CT.

    True

    Gilley found displacement on CT in 26 to 34% of scaphoid fractures that appeared undisplaced on radiographs. In the series summarised by Davis, displacement assessed on CT or MRI, but not on scaphoid-series radiographs, predicted the outcome of cast treatment.

    • Gilley E, Puri SK, Hearns KA, Weiland AJ, Carlson MG. Importance of Computed Tomography in Determining Displacement in Scaphoid Fractures. J Wrist Surg. 2017;7(1):38-42. PMID 29383274
    • Davis TR. Prediction of outcome of non-operative treatment of acute scaphoid waist fracture. Ann R Coll Surg Engl. 2013;95(3):171-6. PMID 23827286