BACKGROUND: Alkaptonuria is a rare single-gene disorder characterized by black pigmentation of cartilage and other connective tissues. Premature degenerative arthritis affects the large joints in many of these of patients. Medical treatment is limited to a protein-restricted diet (phenylalanine and tyrosine) with surgery reserved for end-stage joint disease. As in other metabolic bone diseases, there are concerns about the quality and strength of affected bones and therefore the suitability and longevity of replacement arthroplasty. The histopathology and outcome of joint replacement for alkaptonuric arthritis is unknown and limited to sporadic case reports. PATIENTS AND RESULTS: We describe 11 joint replacements in 3 patients with alkaptonuric polyarthropathy, including shoulder and elbow replacements not previously reported. No prosthetic failures occurred in up to 12 years of follow-up. INTERPRETATION: Total joint replacement is an acceptable treatment for degenerative joint disease in alkaptonuric patients, with implant survival comparable to that found in patients with osteoarthritis.