Alkaptonuric ochronosis.

Alkaptonuria, with its sequel, ochronosis, is a rare disease, with an incidence of 1:125,000 to 1:1 million worldwide. Reported cases of ochronotic arthropathy and other orthopedic manifestations are mostly limited to a single family tree, and few cases have been reported. This study highlights 9 previously unreported patients with sporadic presentation and varied orthopedic manifestations of alkaptonuria. Patient age ranged from 34 to 50 years. One patient who had severe arthropathy of the right hip joint along with subcutaneous nodules over both knees and Achilles tendons underwent total hip replacement. Another patient had intramedullary calcification of the femur. An additional patient had associated caries of the spine at L3, L4, and L5, with resolution of symptoms after antitubercular chemotherapy. Another patient had associated features of hyperthyroidism, which was an incidental finding. A further patient had nonunion fracture of the neck of the femur and underwent total hip replacement. The remaining 4 patients had typical features of low backache and arthritis of the large joints. The parents were nonconsanguineous, and only 2 patients had affected siblings. The remaining 7 patients had sporadic nonfamilial presentation. Diagnosis was established by typical clinical and radiologic findings and biochemical analysis. At 2 years of follow-up, both patients who underwent total hip replacement were normal, with no radiologic signs of loosening or lysis. Clinicians need a high index of suspicion and awareness to make the diagnosis of ochronosis. The current study is unique because of presentation with subcutaneous nodules in 1 patient and associated caries of the spine in another patient.