Cementless total knee arthroplasty in ochronotic arthropathy - A case report with a 4-year follow-up

Alkaptonuria is an inherited metabolic disorder characterized by the absenc e of the enzyme homogentisic acid oxidase, which leads to the accumulation of homogentisic acid, produced during normal metabolism of phenylalanine an d tyrosine. Ochronosis, which is the dark pigmentation of connective tissue s in patients with long-lasting alkaptonuria, can cause severe cartilage de struction in large joints and the vertebral column. Knee joint involvement, which occurs at relatively early ages, can be quite restrictive. Arthropla sty may be the treatment of choice in these patients because of limited mob ility and diffuse involvement of the joint. We report a 48-year-old man who bad been treated with cementless total knee arthroplasty. Theoretically, t here are no bone ingrowth deficits that might be detrimental for the stabil ization of cementless prostheses in ochronotic arthropathy because the bone tissue is not primarily affected by the disease. The 4-year follow-up of c ementless total knee arthroplasty was satisfactory without any evidence of loosening.