LAUSR

Background Defining of gray scale ultrasound standard reference values of the shoulder joint in childhood and adolescence during maturation. PATIENTS We examined 445 healthy girls and boys between 1 year and 18 years of age. Method A cross-sectional multicentre grey-scale ultrasound study was performed to examine the shoulder joint on both sides. The children were divided according to their gender and were further classified into six age groups, which constituted three-year age ranges, to record anatomical development changes. We measured the capsule-bone distance (BCD) as a representation of the intracapsular cavity, as well as the thickness of the joint capsule and joint cartilage. Values were expressed in mean±standard deviation (SD) and minimum-maximum (min-max). The shape of the joint capsule and capsule-bone junction zone was qualitatively analysed. Results The joint cartilage thickness decreased with increasing age in all joints independently from sex and body side. However, the BCD and the capsule thickness increased with age. There was no intraarticular fluid visible. The joint capsule had a predominantly concave form, whereas the capsule-bone junction was mostly sharp. Discussion This study is the first describing age-related normal values of the intracapsular cavity, joint capsule and cartilage thickness as well as their respective shape in a large cohort of healthy children. Conclusion The findings could be helpful to differentiate between physiological and pathological joint conditions and thereby distinguishing age-related variations from alterations caused by inflammation.