Total Knee Arthroplasty in Alkaptonuric Ochronosis: the First Case Report in Thailand and Literature Review

Abstract

Ochronosis is a musculoskeletal manifestation found in alkaptonuria which is a rare autosomal recessive disorder caused by the deficiency of homogentistic acid oxidase enzyme. This leads to accumulation and deposition of homogentistic acid (HGA) pigments in skin, sclera, tendon, ligament and cartilage. Ochronosis is asymptomatic until ochronotic arthropathy occurs. We reported a case of 64-year female presented with advanced degenerative changes in the knee, hip, shoulder and lumbo-sacral spine. The operative findings during total knee arthroplasty showed bluish-black discoloration of the entire articular surface. Her urine HGA level was extremely high. Histopathological exam confirmed ochronosis. The literature, differential diagnosis and management of this rare condition are reviewed.