Abstract

Alkaptonuria is a rare metabolic disease caused by a partial or total deficiency of homogentisic acid oxidase, which results in excess homogentisic acid (HGA) levels. Homogentisic acid and its oxidation products can accumulate in hyaline cartilage, tendons, and ligaments. A 55-year-old male was admitted complaining of worsening chronic pain in his left knee. A radiographic evaluation showed tricompartmental end- stage osteoarthritis. A cemented total knee replacement was performed. At the 10-year follow-up, he had returned to full activity, had no knee pain, and was very satisfied with the outcome. No abnormality was observed in the femoral, tibial, or patellar components on radiography. We believe that total knee replacement is a good option in a patient with marked degenerative arthritis secondary to ochronotic arthritis.