Contributor: Nick Tsipis MD

Educational Pearls:

The scaphoid bone is the most proximal carpal bone just distal to the radius
Fractures of the scaphoid bone are sometimes missed by plain X-rays

A 2020 review found a 21.8% incidence of missed scaphoid fractures later diagnosed by advanced imaging modalities
Only MRI has a sensitivity above 90% for diagnosing scaphoid fractures
Sensitivity of plain-film radiography is low unless it is a displaced fracture

Physical examination techniques fail to definitively rule out scaphoid fractures
A 2023 systematic review assessed the sensitivity and specificity of several common physical exam maneuvers:

Tenderness of the anatomical snuffbox has a sensitivity of 92.1% and specificity of 48.4%; i.e. absence reduces the likelihood of an occult scaphoid fracture but does not rule it out
Another common physical exam maneuver is pain with ulnar deviation, which carries a sensitivity of 55.2% and specificity of 76.4%.
Elicitation of pain with supination against resistance demonstrated a sensitivity of 100% and specificity of 97.9% in the study, so the authors recommend externally validating this method

Patients should be counseled on the importance of follow-up given that a fracture may not show up on imaging unless an MRI or repeat XR is done

References

1. Bäcker HC, Wu CH, Strauch RJ. Systematic Review of Diagnosis of Clinically Suspected Scaphoid Fractures. J Wrist Surg. 2020;09(01):081-089. doi:10.1055/s-0039-1693147

2. 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 LP - 582. doi:10.1136/emermed-2023-213119

Summarized by Jorge Chalit, OMSII | Edited by Meg Joyce & Jorge Chalit, OMSII

Episode 867: Occult Scaphoid Fractures

Emergency Medical Minute