Total knee prosthesis in a patient diagnosed with ochronotic arthropathy.

Ochronosis is a rare genetic disease of phenylamine and tyrosine metabolism in which an accumulation of homogentisic acid occurs. The accumulation of HGA causes alkaptonuria and deposition in the connective tissue causing a dark colouring of the tissue. In the joints, it can lead to early and very disabling arthropathy, known as ochronotic arthropathy. We present the case of a patient diagnosed with ochronosis and ochronotic arthropathy of the left knee, in which we describe the intraoperative process with the macroscopic and microscopic anatomopathological findings. The patient made good progress after implantation of a total knee prosthesis (TKP), PS type, and was able to follow the same rehabilitation protocol used in patients without ochronotic arthropathy undergoing TKP. The patient showed improvement in the different functional scales, as well as disappearance of pain.