TJA in Rare Conditions
- Alkaptonuria is a rare autosomal recessive metabolic disorder. It is characterized by the accumulation of homogentisic acid in the body due to a lack of enzymes that degrade it. Over time, it results in joint degeneration and eventually leads to ochronosis. Ochronosis refers to bluish-black discoloration of connective and other tissues within the body. In this study, we present 5 distinct cases diagnosed with alkaptonuria. They have undergone 8 total joint replacement surgeries (4 hips and 4 knees) within 8 years (2010-2018).
- Alkaptonuria is disorder of tyrosine metabolism due to deficiency of homogentisic oxidase characterized by excretion of homogentisic acid in urine, deposition of oxidized homogensitate pigments in connective tissues and articular cartilages (ochronosis). The result is dark pigmentation and weakening of the tissues resulting in chronic inflammation and osteoarthritis. Management of alkaptonuric ochronic osteoarthritis is usually symptomatic and replacements have comparable outcomes to osteoarthritis in patients without ochronosis.