Thalassemic osteoarthropathy.

Patients with beta thalassemia major may develop a specific osteoarthropathy as they approach the second and third decades of life. Twenty-five of 50 patients between the ages of 5 and 33 years had evidence of periarticular disease that consisted of dull-aching ankle pain exacerbated by weight bearing and relieved by rest. Involvement was symmetrical with mild swelling and pain on bone compression. Arthrocentesis showed no evidence of inflammation. Radiographic changes included osteopenia, widened medullary spaces, thin cortices with coarse trabeculations, and evidence of microfractures. Histologic studies confirmed the presence of microfractures and showed osteomalacia and an increase in osteoblastic and osteoclastic surface area with iron deposites at the calcification front and cement lines. The relative roles of iron overload, divalent cation metabolism, erythroid hyperplasia, or other factors in the pathogenesis of the syndrome remain unknown, and no specific therapy can be recommended at present.