Scaphoid Fracture – Can PoCUS disrupt the traditional ‘splint and wait’ pathway?

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PoCUS Fellow Pearl

Dr. Melanie Leclerc, CCFP-EM

MSK PoCUS Fellow

Dalhousie University Department of Emergency Medicine

 

Reviewed & Edited by Dr David Lewis (@e_med_doc)

All case histories are illustrative and not based on any individual

 

Case:

A 37 year old, right hand dominant, carpenter presents to your local ED with a complaint of right wrist pain. He was on a step-stool and lost his balance earlier today. He fell landing on his outstretched arm and had an acute-onset of radial-sided wrist pain. He denies any other injury. There are no neurologic complaints.

On exam, there is no visible deformity. The skin is closed and there is some swelling noted. The patient is tender over the anatomic snuff box as well as volarly over the scaphoid. There is pain noted with axial loading of the thumb. There is no other tenderness. ROM is within normal limits. The limb is distally neurovascularly intact.

X-rays are normal.

An occult scaphoid fracture is suspected. At this institution, patients with suspected occult scaphoid fracture are placed in a thumb spica splint and referred to the local hand surgeon to be seen in ~10-14 days for repeat assessment and X-ray.

Can Point of Care Ultrasound change this traditional “splint and wait” patient pathway?

 

Background:

Scaphoid fracture is a common presentation to the Emergency Department accounting for approximately 15% of all wrist injuries and 70% of carpal fractures. Up to 30% of the time, radiographs at initial presentation appear normal making fracture a commonly missed injury for Emergency physicians. A failure to recognize this injury can lead to chronic pain and functional impairment for patients. Particularly, fractures of the proximal pole (most distant to the blood supply) can lead to avascular necrosis (AVN) at high rates. Non-union can lead to scaphoid non-union advanced collapse (SNAC wrist) which can perpetuate further degenerative changes throughout the carpus. This can cause a significant impact on quality of life and occupation. Early detection of fracture could expedite fixation and possibly results in better outcomes. Further study in this area is needed.

 

Anatomy:

The scaphoid bone lies in the radial aspect of the proximal carpal row. It’s unique shape (“twisted peanut”), lends to easy recognition. It articulates proximally with the distal radius, distally with the trapezium, and on its’ ulnar aspect with the lunate to form the scapho-lunate interval. The blood supply to the scaphoid is unique in that the majority of it is retrograde. The dorsal carpal branch of the radial artery supplies the bone from distal to proximal. A small proportion of the blood supply originates at the proximal end. The boundary between the two supplies creates a “watershed” area prone to non-union and AVN.

 

Classification of Fractures:

Scaphoid fractures are classified by location. These regions are the proximal, middle and distal thirds which account for 20%, 75%, and 5% of the fractures respectively. The stability of fractures is determined by the displacement (>1mm) and angulation (scapholunate angle >60 and radiolunate angle >15). The Hebert Classification as endorsed by Traumapedia can be found below.

 

Traditional Imaging:

Imaging of these suspected injuries varies. Traditionally serial X-rays were used, but have been found to be poorly sensitive even several weeks after injury. Bone scan has also been used as an alternative due to it’s high sensitivity, but has poor specificity and provides no further information regarding the nature of the fracture. CT is relatively sensitive and specific and provides information for pre-operative planning. MRI is considered the gold standard, but is difficult to obtain in a timely manner in Canada.

Bäcker HC, Wu CH, Strauch RJ. Systematic Review of Diagnosis of Clinically Suspected Scaphoid Fractures. J Wrist Surg. 2020 Feb;9(1):81-89. doi: 10.1055/s-0039-1693147. Epub 2019 Jul 21. PMID: 32025360; PMCID: PMC7000269.

 

PoCUS Technique:

  • Linear probe

  • Consider waterbath, gel standoff pad, or bag of IV fluid

  • Scan with the wrist ulnarly deviated

  • Scan in the longitudinal and transverse orientations of volar, lateral and dorsal aspects

  • Place the probe in longitudinal orientation dorsally over lister’s tubercle of the radius and scan distally until the scaphoid is visualized in the snuff box. Scan radial to ulnar.

  • Rotate to the transverse orientation and scan through proximal to distal

  • Volarly, in the transverse plane, identify the tendon of the flexor carpi radialis (this lies radial to the easily identifiable palmaris longus tendon on exam). The scaphoid is found deep to this. Scan proximal to distal.

  • Rotate to the longitudinal orientation and scan radial to ulnar

 

 

Video Demonstration:

 

 

Findings:

  • Cortical disruption

  • Periosteal elevation

  • Hematoma

 

The Evidence:

  • Early advanced imaging (CT or MRI) compared to initial 2 week immobilisation proved more cost effective and had better patient oriented outcomes (ie. missed work).(7)
  • A systematic review and meta analysis of moderate to high quality studies published in 2018 found that ultrasound had a mean sensitivity of ~89% and specificity of ~90% for detection of occult scaphoid fractures.(1)
  • Similar results were also reported by another systematic review in 2018.(8)
  • Pocus was shown to have a comparable sensitivity to CT for occult scaphoid in a systematic review published in 2020.(2)

 

Limitations:

  • Only useful if positive
  • Operator experience dependent
  • US probe and frequency dependant
  • Potential for false positives due to injury of nearby structure causing hematoma
  • Potential for false positives in context of arthritis or remote trauma

 

Bottom line:

  • Useful if positive
  • Still need definitive test to further delineate fracture (ie: for operative planning)
  • Could expedite CT
  • Could expedite specialist follow-up
  • May improve ER physician diagnostic certainty
  • May improve patient trust and compliance with splinting
  • Further study is needed

 

Case Conclusion:

Scaphoid cortical disruption was visualized using PoCUS. After discussion with the hand surgeon, a CT Scan of the wrist was performed which confirmed a minimally displaced waste fracture of the scaphoid. The patient was splinted and seen the next day in clinic for discussion regarding operative management.

 

Further Review:

 

 

 

References

  1. Ali M, Ali M, Mohamed A, Mannan S, Fallahi F. The role of ultrasonography in the diagnosis of occult scaphoid fractures J Ultrason 2018; 18: 325–331.
  2. Bäcker HC, Wu CH, Strauch RJ. Systematic Review of Diagnosis of Clinically Suspected Scaphoid Fractures. J Wrist Surg. 2020 Feb;9(1):81-89.
  3. Bakur A. Jamjoom, Tim R.C. Davis. Why scaphoid fractures are missed. A review of 52 medical negligence cases, Injury, Volume 50, Issue 7, 2019, Pages 1306-1308.
  4. Carpenter CR et al. Adult Scaphoid Fracture. Acad Emerg Med 2014; 21(2): 101-121.
  5. Gibney B, Smith B, Moughty A, Kavanagh EC, Hynes D and MacMahon PJ American Journal of Roentgenology 2019 213:5, 1117-1123
  1. Jenkins PJ, Slade K, Huntley JS, Robinson CM. A comparative analysis of the accuracy, diagnostic uncertainty and cost of imaging modalities in suspected scaphoid fractures. Injury. 2008;39:768–774.
  2. Karl, John W. MD, MPH1; Swart, Eric MD1; Strauch, Robert J. MD1 Diagnosis of Occult Scaphoid Fractures, The Journal of Bone and Joint Surgery: November 18, 2015 – Volume 97 – Issue 22 – p 1860-1868.
  3. Kwee, R.M., Kwee, T.C. Ultrasound for diagnosing radiographically occult scaphoid fracture. Skeletal Radiol 47, 1205–1212 (2018).
  4. Malahias MA, Nikolaou VS, Chytas D, Kaseta MK, Babis GC. Accuracy and Interobserver and Intraobserver Reliability of Ultrasound in the Early Diagnosis of Occult Scaphoid Fractures: Diagnostic Criteria and a Way of Interpretation. Journal of Surgical Orthopaedic Advances. 2019 ;28(1):1-9.
  5. Mallee WH, Wang J, Poolman RW, Kloen P, Maas M, de Vet HCW, Doornberg JN. Computed tomography versus magnetic resonance imaging versus bone scintigraphy for clinically suspected scaphoid fractures in patients with negative plain radiographs. Cochrane Database of Systematic Reviews 2015, Issue 6.
  6. Mallee, W.H., Mellema, J.J., Guitton, T.G. et al. 6-week radiographs unsuitable for diagnosis of suspected scaphoid fractures. Arch Orthop Trauma Surg 136, 771–778 (2016).
  7. Melville, D., Jacobson, J.A., Haase, S. et al. Ultrasound of displaced ulnar collateral ligament tears of the thumb: the Stener lesion revisited. Skeletal Radiol 42, 667–673 (2013).
  8. Meyer, P., Lintingre, P.-F., Pesquer, L., Poussange, N., Silvestre, A., & Dallaudiere, B. (2018). Imaging of Wrist Injuries: A Standardized US Examination in Daily Practice. Journal of the Belgian Society of Radiology, 102(1), 9.
  9. Mohomad et al. 2019. Accuracy of the common practice of doing X-rays after two weeks in detecting scaphoid fractures. A retrospective cohort study. Hong Kong Journal of Orthopaedic Research 2019; 2(1): 01-06.
  10. Neubauer J, Benndorf M, Ehritt-Braun C, et al. Comparison of the diagnostic accuracy of cone beam computed tomography and radiography for scaphoid fractures. Sci Rep 2018; 8:3906.
  11. Ravikant Jain, Nikhil Jain, Tanveer Sheikh, Charanjeet Yadav. 2018. Early scaphoid fractures are better diagnosed with ultrasonography than X-rays: A prospective study over 114 patients, Chinese Journal of Traumatology, Volume 21, Issue 4, Pages 206-210.
  12. Senall, JA, Failla, JM, Bouffard, JL. 2004. Ultrasound for the early diagnosis of clinically suspected scaphoid fracture. J Hand Surg Am, 29:400-405.
  13. https://essr.org/content-essr/uploads/2016/10/wrist.pdf
  14. http://www.bonetalks.com/scaphoid
  15. https://radiopaedia.org/articles/scaphoid-fracture
  16. https://sketchymedicine.com/2014/07/scaphoid-bone-anatomy-and-fractures/
  17. https://radiopaedia.org/cases/scaphoid-fracture-11?lang=gb
  18. https://www.orthobullets.com/hand/6034/scaphoid-fracture
  19. https://meeting.handsurgery.org/abstracts/2018/EP15.cgi
  20. https://www.researchgate.net/figure/Bone-scintigraphy-patient-C-of-the-hands-the-patient-with-a-scaphoid-fracture-on-the_fig4_50399987
  21. https://www.youtube.com/watch?v=7pCXiRQMRKo&t=5s&ab_channel=UltrasoundPod
  22. https://litfl.com/terry-thomas-sign
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