Normative ultrasound references for the paediatric wrist; dorsal soft tissues

Abstract

Objective: To report novel ultrasound (US) references for the healthy paediatric wrist.

Methods: Healthy children and adolescents had an US examination including Doppler, of the right wrist, using a mid-sagittal image through the radiocarpal (RC)/midcarpal (MC) joints. These features were noted: appearances and depth of the recess, with an additional measurement in the flexed position and number of Doppler signals within the recess in close proximity to the joint. In a second, blinded session, all images were reassessed by the same observer.

Results: In total, 116 subjects (59 girls) aged 6-16 years (mean 10 years and 11 months) were included. The RC recess was visible in 71, of which 60 were non-bulging and 11 were bulging. In flexion, the thickness decreased in 60 (84.5%), suggestive of joint fluid. Of the 54 visible MC recesses, 45 (83.3%) thinned in flexion. The mean depths of the RC and MC recesses were 0.4 mm (SD 0.5, range 0-2.9) and 0.5 mm (SD 0.6, range 0-2.4), respectively, with no differences according to sex, but with increasing depths by age.For the RC joints, at least one Doppler signal was seen in the recess in 9/116 joints (7.8%), whereas this was true for 3.5% of the MC recesses. There were no statistically significant association between the depth of the RC or MC recesses and number of hand active sport activities (P=0.733 and P=0.091, respectively).

Conclusion: The appearances of the dorsal RC and MC recesses in healthy children may mimic pathology. Hence, findings should be interpreted carefully.

Keywords: juvenile idiopathic arthritis; synovial fluid; ultrasonography.

Figure 1

A mid-sagittal view through the dorsum of the wrist in (A) a 7-year-old, healthy girl. The RC recess is visible (score 1, short arrow), whereas the MC recess does not show (score 0) and in (B) a 9-year-old, healthy boy showing bulging MC (score 2, long arrow) and RC (score 2, stippled arrow) recesses. *4th compartment of the extensor tendons. C, capitate; E, distal–radial epiphysis; L, lunatum; MC, midcarpal; R, distal radius; RC, radiocarpal.

Figure 2

Mid-sagittal US images in an 11-year-old boy with the wrist in (A) neutral position showing a bulging MC recess (measured from the surface of the capitate to the junction between hypoechoic and hyperechoic tissue, double arrow) and in (B) flexed position showing a reduced depth (stippled arrow). MC, midcarpal; US, ultrasound.

Figure 3

Mid-sagittal US images showing vessels in the RC recesses of (A) a 13-year-old girl and of (B) an 11-year-old boy. (C) A vessel in the radial epiphysis in a 7-year-old girl and (D) in the MC recess of a 10-year-old boy. MC, midcarpal; RC, radiocarpal; US, ultrasound.