Our MRI studies showed a significant increase in synovitis and synovial effusion in the early stages of LCPD.(32, 33) Intriguingly, one of the proinflammatory cytokines, IL‐6, was significantly elevated in the synovial fluid of the affected hip (500 to 1000 pg/mL) compared with controls (<30 pg/mL).(32). The gene discussed is IL6; the disease is Legg-Calve-Perthes disease.