INCREASED PREVALENCE OF JUVENILE OSTEOCHONDRITIS DISSECANS IN PATIENTS WITH JUVENILE IDIOPATHIC ARTHRITIS

Background: Juvenile Idiopathic Arthritis (JIA) is an autoimmune disorder presenting with chronic arthritis with prevalence of 5-20/100,000. Juvenile osteochondritis dissecans (OCD) is an idiopathic disease of articular cartilage and subchondral bone, has onset at 10-16 years, often affects the knee and ankle with prevalence of 5-30/100,000. Hypothesis/Purpose: We hypothesize that OCD is more prevalent in JIA, and when diagnosed in JIA, OCD is advanced, often requiring surgery. Methods: This was a retrospective review of patients with JIA and OCD treated between January 2008 and March 2019 at one children’s hospital. We queried Department of Rheumatology records for JIA patients treated during this interval as well as Departments of Orthopedics and Radiology records for patients with OCD. Demographic information, classification of the stability of OCD lesions by review of magnetic resonance imaging, and clinical details of treatment were recorded. Results: 2,021 JIA patients were identified, 20 of whom (19 girls, 1 boy) had OCD of the knee and/or talus for a prevalence of 1/100 or 1000/100,000, or approximately 30-200x that of the general population. These 20 patients had a total of 28 OCD lesions: 43% (9 femur, 3 talus) were radiographically stable over time, 50% (10 femur, 2 patella, and 2 talus) were unstable at initial diagnosis, and 7% (femur) were initially stable but progressed to unstable lesions despite drilling. Eleven patients (55%) underwent surgery: 5 with stable femoral lesions for persistent symptoms despite prolonged non-operative treatment, and 6 for treatment of their unstable lesions (femur and patella). Of these 11 patients, 3 underwent two or more surgeries for OCDs, and 3 were treated with hemiepiphysiodesis for concomitant genu valgum. Conclusion: OCD lesions are 30-200x more prevalent in JIA compared to the general population. In JIA, OCD often presents at an advanced stage requiring surgery for stabilization. Patients with JIA may benefit by early screening, to potentially allow for treatment of an OCD lesion prior to the progression to instability.