What is the role of ultrasonography in the early diagnosis of scaphoid fractures?

Abstract

Scaphoid fractures are the most prevalent type of carpal bone fractures. High-spatial-resolution sonography detects direct signs of scaphoid fractures such as scaphoid cortical disruption; nevertheless, indirect signs such as radiocarpal effusion and scapho-trapezium-trapezoid effusion can also be visible. The diagnosis is performed when both direct and indirect signs of scaphoid fracture are presented. The presence of indirect signs alone is not enough to complete the diagnosis, for which more advanced imaging modalities are usually required. Here, we review the anatomy of the scaphoid, the clinical manifestations of scaphoid fractures, as well as ultrasonographic findings and differential diagnosis.

Keywords: ASB, anatomical snuffbox; Bone; CT, computed tomography; Diagnostic imaging; Fractures; LC, longitudinal compression; MRI, magnetic resonance imaging; NPV, negative predictive value; PPV, positive predictive value; ST, scaphoid tubercle; Scaphoid bone; US, high-spatial-resolution sonography; Ultrasonography.

Fig. 1

Blood supply of the scaphoid coming from the distal pole. (A) Distal pole. (B) Scaphoid tubercle. (C) The waist of the scaphoid. (D) Proximal pole. (E) Radial artery.

Fig. 2

(A) Peanut-shaped appearance of the scaphoid (arrow) in the volar view. (B) Pyramid appearance of the scaphoid (arrow) in the dorsal view.

Fig. 3

A normal scaphoid. The palmar cortex of the scaphoid (S), radius palmar cortex (R), joint capsule (c), and flexor carpi radialis tendon (t).

Fig. 4

Photograph of the exact location of the linear probe used to image the scaphoid bone. Position of the linear probe when scanning the scaphoid bone from the dorsal (a), dorsal with ulnar deviation (b), and volar surface (c). R: radius, T: scaphoid tuberosity

Fig. 5

A Split-Screen comparison of the fractured scaphoid (right) and healthy scaphoid (left). The arrows distinguish two cortical fractures in the palmar cortex. Reprinted with permission from Senall et al. (2004).

Fig. 6

Scaphoid US showing cortical disruption. (a) Disruption in the cortex of the scaphoid (arrow) consistent with a scaphoid fracture. (b) Scaphoid fracture with minor cortical defect (arrow). Reprinted with permission from Simard et al. (2020) and Dickman et al. (2014), respectively.

Fig. 7

A Split-Screen comparison of the US image of the harmed (I) and the healthy side (II). The scaphoid's cortex (arrow A) shows a disruption line (arrow B) on the harmed side. The space from the broken scaphoid's cortex to the skin (arrow C) is enlarged in contrast to the healthy side. There is a hematoma (small arrows) on the affected side. The cortex of the radius is marked (arrow D). Reprinted with permission from Munk et al. (2000).

Fig. 8

A sagittal oblique image through the scaphoid's waist shows a fracture with cortical step-off (larger 2 arrows), shown magnified in the inset. The proximal pole is to the left, and the tuberosity is to the right. A fluid collection is seen anterior to the fractured palmar-radial cortex (smaller 3 arrows). The fibrillar pattern of the flexor carpi radialis tendon (arrowhead) is seen anterior to the scaphoid. Reprinted with permission from Senall et al. (2004).

Fig. 9

Longitudinal high-spatial-resolution sonogram obtained in the dorsal direction in a 21-year-old man with a scaphoid fracture after acute trauma of the left wrist clearly shows a hyperechogenic line parallel to the scaphoid cortex (solid arrows) and cortical discontinuity (open arrows). Reprinted with permission from Herneth et al. (2001).