A83: Power Doppler Visualization of Epiphyseal and Growth Plate Vascularity in Affected and Contralateral Unaffected Joints in Patients with Juvenile Idiopathic Arthritis

Background/Purpose: Children with juvenile idiopathic arthritis (JIA) may develop limb asymmetry, thought to be mediated by growth plate hyperemia adjacent to areas of synovial inflammation. Synovial hyperemia signifies active inflammatory arthritis in adults and vessels visible within in the joint capsule are considered abnormal. In growing children, however, blood vessels supplying the growth plate and surrounding areas are frequently visible sonographically even in unaffected joints, but have not been described systematically. We used power Doppler (PD) to compare epiphyseal and growth plate vascularity in affected and contralateral unaffected joints in children with clinically asymmetric inflammatory arthritis. Methods: Children between 2 and 16 years of age who had clinical joint swelling in one ankle or knee but not the contralateral joint were examined with gray scale (GS) and PD ultrasound using a Philips CX50 machine (5–12 mHz linear transducer). Images (GS) and video clips (PD) were taken at the knees (medial, lateral, posteromedial and posterolateral femoral condyles, medial and lateral proximal tibia, and lateral proximal fibula), or ankles (anterior and medial distal tibia and lateral distal fibula), in addition to standard images to document disease activity. Vessels were noted as present or absent in each view, and localized as epiphyseal cartilage, growth plate, or periosteal. Results: Knees of 8 subjects and ankles of 3 subjects were imaged. The most common vessels seen were extraarticular, parallel to the periosteum but not visibly entering cartilage or joint spaces. Vessels were visible in the epiphyseal cartilage in the majority of the lateral femur, medial femur, and anterior distal tibial views, and less frequently in the posterolateral femoral condyle, posteromedial femoral condyle, proximal lateral tibia, proximal medial tibia, and proximal fibula. Four subjects had vessels seen within the growth plate; 3 of these were in the lateral aspect of the knee, and one in the anterior ankle.1 Table 1. Visible vessels by location* total ≥ of paired views Knee distal lateral femur distal medial femur posterolateral femur posteromedial femur proximal medial tibia proximal lateral tibia proximal fibula Ankle distal anteriortibia distal medialtibia distal fibula n = 8 n = 6 n = 7 n = 7 n = 6 n = 8 n = 7 n = 3 n = 3 n = 3 a u a u a u a u a u a u a u a u a u a u a=affected, u=unaffected. a number(percentage) epiphyseal 5 (63)a 6 (75) 4 (67) 4 (67) 1 (14) 0 (0) 2 (29) 0 (0) 2 (33) 2 (33) 3 (38) 3 (38) 1 (14) 2 (29) 1 (33) 2 (67) 0 (0) 0 (0) 0 (0) 0 (0) growth plate 2 (25) 0 (0) 0 (0) 0 (0) 0 (0) 0 (0) 0 (0) 0 (0) 0 (0) 0 (0) 1 (13) 2 (25) 0 (0) 0 (0) 1 (33) 0 (0) 0 (0) 0 (0) 0 (0) 0 (0) periosteal 5 (63) 7 (88) 6 (100) 5 (83) 4 (57) 3 (43) 2 (29) 0 (0) 4 (67) 4 (67) 7 (88) 7 (88) 2 (29) 2 (29) 0 (0) 0 (0) 0 (0) 0 (0) 0 (0) 0 (0) Conclusion: This is the first study to our knowledge that specifically addresses the sonographic appearance of vessels within the growth plate and epiphyseal cartilage in JIA. These vessels were readily seen, especially within the epiphyseal cartilage, suggesting that this methodology is appropriate for further study. There was no clear difference between vascularity of clinically swollen and unaffected joints. Though this was a small population, this finding raises questions about hyperemia as the mechanism leading to the growth asymmetry seen in children with JIA. Future work should include a larger population, greater age representation to explore differing vascularity related to age and pubertal status, and healthy controls.