Calcaneal Avulsion of an Ochronotic Achilles Tendon: A Case Report.

Alkaptonuria is a hereditary disorder of phenylalanine and tyrosine, with an incidence of approximately 1/200,000 to 1/1,000,000. Ochronosis is the accumulation of homogentisic acid and its metabolites in connective tissues such as the tendons, cartilage, and skin. In the present case study, a 50-year-old male presented with a nontraumatic calcaneal avulsion without a previous diagnosis of ochronosis. To the best of our knowledge, little information has been reported of this pathology in the Achilles tendon and the surgical management.