Black meniscus: Ochronosis as a finding during arthroscopic procedure

Abstract

Ochronosis is a sign caused by the accumulation of homogentisic acid in collagen-rich connective tissues. The disease underlying this disorder is alkaptonuria, a rare metabolic disorder in the catabolism of tyrosine and phenylalanine.

We present the cases of two patients with meniscal tears whose diagnosis of alkaptonuria was verified after the arthroscopic finding of black pigmentation in the tissues of the knee.