summary Ochronosis is a metabolic arthropathy caused by alkaptonuria with excess homogentistic acid deposited in the joints. Patients present with early degenerative joint disease, spondylitis, and black urine. Diagnosis is made with detection of homogentisic acid in urine. Treatment is similar to that of osteoarthritis with observation, NSAIDs, tramadol and corticosteroids for mild to moderate symptoms. Arthroplasty is indicated for severe symptoms. Etiology Pathophysiology excess homogentistic acid is deposited in the joints acid polymerizes in joint and leads to early joint arthritis Genetics rare inborn defect in homogentisic acid oxidase enzyme system Associated conditions orthopaedic manifestations ochronotic spondylitis login to view 4 more bullets Presentation Symptoms may complain of black urine caused by polymerization of homogentistic acid Imaging Radiographs spine findings login to view 2 more bullets Treatment Nonoperative no current medical treatment available