Destructive synovitis in contralateral Perthes' disease. A report of 2 cases.

2 boys had unilateral Perthes' disease at the age of 5 years. After 6 and 7 years, respectively, both patients developed contralateral femoral head necrosis with rapid destruction leading to ankylosis of the hip. Histology of the synovium showed nonspecific synovitis. Both patients fulfilled criteria for oligo-articular juvenile chronic arthritis (JCA). The association with Perthes' disease suggests a common etiology.