Synovial chondromatosis.

Two patients were evaluated for a complaint of long-standing hip pain. No etiology of their progressively disabling symptoms was found by routine diagnostic studies. Hip arthrography and arthrotomography in each case, however, demonstrated multiple intraarticular filling defects consistent with nonradiopaque loose bodies. These were subsequently confirmed at arthrotomy. Synovial chondromatosis is a rare disease in which intrasynovial cartilage metaplasia results in multiple intracapsular loose bodies. Its presence in plain radiographs is uncommon, but has been previously documented. This can account for frequent long delays in accurate diagnosis. Arthrography and/or arthrotomography, however, can be key diagnostic tools. They are recommended in the evaluation of patients whose relatively normal initial clinical examination, laboratory, and roentgenographic studies fail to adequately explain the presence of genuinely disabling symptoms.