Application of ultrasound in the management of TRASH (the radiographic appearance seemed harmless) fractures in preschool children: A review

Abstract

Elbow fracture is one of the most common fractures in preschool children, and the secondary ossification center appears regularly with age increasing. Transphyseal separation of the distal humerus, medial humeral condyle fracture, lateral humeral condyle fracture, radial head osteochondral separation, and Monteggia fracture (minimal ulnar bow type) are difficult to diagnose based on X-ray films alone because of the unossified secondary ossification center or a suspicious non-alignment of the anatomical cartilage of the elbow joint in preschool children. These 5 fractures above are defined as The Radiographic Appearance Seemed Harmless fractures in preschool children (TRASH-PS). The TRASH-PS fractures must be taken into consideration when there is swelling at the injured site without fracture feature on X-ray. Additionally, relevant misdiagnosis or unsuitable management can lead to elbow dysfunction and deformity. Therefore, this work reviews the application of ultrasound in the management of TRASH-PS fractures.

Figure 1.

These are pictures of the ultrasound examination positions and mapping related scans of a 4-yr-old boy. (A) On the transverse scan, the normal articular cartilage of distal humeral was clearly showed as a continuous, black, and waving shape (yellow stars). (B) On the coronal longitudinal scan, it showed that there were normal “double-hump sign” and “congruency sign” in radio-capitellum joint. (C) The sagittal longitudinal scan of ultrasound showed that the supinator muscle was advanced and annular ligament was entrapped, indicating a “hook sign” (yellow arrow). C = capitellum; MD = medial condylar; RH = radial head; SM = supinator muscle.

Figure 2.

A 1-yr-old boy was diagnosed with a transphyseal separation of the distal humerus. (A) X-ray showed a dislocation-like fracture of the elbow joint. (B) The coronal longitudinal scan of ultrasound showed that there was a normal alignment in radio-capitellum joint and the capitellum was separated from distal humer. C = capitellum; H = humer, RH = radial head.

Figure 3.

(A) A 5-yr-old boy, X-ray image showed swelling of the medial soft tissue and a thin “C” shaped fracture fragment (yellow arrow) was visible. (B) The transverse ultrasound scan showed that the cartilage of medial condyle was displaced (yellow arrow) from cartilage hinge of distal humer (yellow star).

Figure 4.

(A) A 4-yr-old boy, a slightly avulsion fracture of the lateral condylar of humerus can be seen on the anteroposterior film (arrow). (B) A slightly avulsion fracture was latent on the lateral film. (C) The transverse ultrasound showed the accumulated articular cartilage gap (white arrow) and step-off (yellow arrow) of the fracture. (D) The longitudinal ultrasound showed the fracture gap (yellow arrow) was much clearer on ultrasound than the ones in X-ray. C = capitellum, H = humer.

Figure 5.

(A) A 5-yr-old boy, the displacement fragment was barely visible (yellow arrow) on the anteroposterior radiograph film. (B) There was an overlapping fracture shadow on the lateral film behind the proximal ulna (yellow arrow). (C) The sagittal longitudinal ultrasound scan showed obvious displacement of the radial head and a metaphyseal fracture line (yellow arrow), but the radial head was disappeared (white arrow). (D) Ultrasound showed normal “double-hump sign” and “congruency sign” after closed reduction. C = capitellum, RH = radial head, RS = radial shaft.

Figure 6.

(A) A 5-yr-old girl, the fracture of the ulna was displaced on the X-ray lateral view, and the axis of the radial neck passed through the upper 1/3 of the capitellum (arrow). (B) The axis of the radial neck passed through the middle 1/3 of the capitellum after ultrasound monitoring closed reduction. (C) Ultrasound showed obvious displacement of the radial head with soft tissue incarceration (arrow) before reduction. (D) Ultrasound showed normal “double-hump sign” and “congruency sign” after closed reduction (arrow). C = capitellum, RH = radial head.