Normative ultrasound references for the paediatric wrist; dorsal soft tissues.

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.