Avascular necrosis in pediatric rheumatic diseases: an Italian retrospective multicentre study

Atraumatic avascular necrosis (AVN) is a severe condition that may complicate the course of rheumatic diseases and contribute to long-term damage. However, there is a lack of evidence on this rare event in pediatric rheumatology. The aim of our study was to evaluate the occurrence of avascular necrosis in the context of rheumatologic diseases in Italy and to describe the main demographic and clinical features of AVN patients, with a particular focus on treatment background.

All centres part of the Italian Society of Pediatric Rheumatology were invited to participate in a retrospective case collection of children with rheumatic diseases complicated by a pediatric-onset AVN. Demographic, clinical, laboratory and imaging data were recorded, together with outcome and treatment background, particularly steroid exposure. Population collected was further evaluated according to the different underlying rheumatologic disease and to the time of AVN onset.

Fourteen patients (SLE = 7; JIA = 4; others = 3) were collected from 7 centres. Females were predominantly affected (71%) with a median age at AVN diagnosis of 14.3 years. Multifocal involvement was mostly reported (93%), mainly involving femoral heads (44%) and knees (28%). All patients had a severe rheumatologic background and received systemic glucocorticoids with a median cumulative prednisone equivalent dose of 457.5 mg/kg. In all patients but one imaging showed persistence of abnormalities, despite the complete resolution of symptoms in 6 of them. Bisphosphonates were the most used therapeutic approach; orthopedic surgery was required in 2 cases.

Despite its rarity, AVN may be a severe complication of pediatric rheumatic diseases. Active monitoring is crucial to promptly identify patients and to prevent long-term damage. Prospective large sample studies are required to better understand the impact of steroid exposure and its complex interplay with other potential contributing factors.