Cystic fibrosis and hypertrophic osteoarthropathy in children. Report of three cases.

Three patients with cystic fibrosis were noted to have swelling of knee and ankle joints during exacerbation of their lung disease. Synovial fluid was analyzed in one patient and the synovium underwent biopsy in another. These studies excluded other causes of arthritis but did not contribute any new information on the nature of secondary hypertrophic osteoarthropathy. Radiological examination of long bones confirmed the diagnosis of hypertrophic osteoarthropathy in all three patients. Since many patients with cystic fibrosis survive longer, more instances of hypertrophic osteoarthropathy are expected in the future.