Knee osteoarthrosis secondary to ochronosis – clinical case

Alkaptonuria is a rare metabolic disease in which a deficiency of the enzyme homogentisate dioxygenase causes an accumulation of homogentisic acid. Ochronosis consists of excessive deposition of homogentisic acid in the connective tissue and presents as a chestnut brown or black pigmentation. With aging, the accumulation of pigments from homogentisic acid in the joints causes osteoarthrosis. There is no specific treatment for the disease and the approach is symptomatic. Arthroplasty is the solution for severe cases of osteoarthrosis caused by this pathological condition and presents results comparable to those from patients with primary osteoarthrosis. Here, the case of a 67-year-old patient who underwent several arthroplasty procedures because of osteoarthrosis caused by this rare pathological condition is presented. The last surgical intervention consisted of total right knee arthroplasty.