Description
Ochronosis is a rare disease. This results from a deficiency of the enzyme homogentisic acid oxidase, which is involved in metabolizing the phenylalanine and tyrosine amino acids. Homogentisic acid and its oxidation products accumulate in the connective tissue like cartilage and tendons. We present a patient who was diagnosed with alkaptonuria after observing ochronotic black pigmentation of the meniscus during arthroscopy of the knee.
We present a patient who was diagnosed with alkaptonuria after observing ochronotic black pigmentation of the meniscus during arthroscopy of the knee. A 49-year-old man presented with complaints of pain in the left knee. The patient had no history of trauma. McMurray’s test applied to the patient was positive. A radial tear of the medial meniscus posterior horn was detected in the left knee's Magnetic Resonance Imaging(MRI) examination. He was planned for arthroscopic repair because of his complaints, physical examination, and MRI findings.
During the arthroscopic examination of the left knee joint, there was found black meniscus and degeneration of the cartilage. The synovial membrane is hyperpigmented black and hypertrophic. A partial meniscectomy was performed due to advanced degeneration in the meniscus of the patient which was planned to be repaired. The patient, who was not aware of this situation before, was planned to be examined in terms of metabolic diseases. The patient was diagnosed with Alkaptonuria after urinalysis and Alkaptonuria HGD gene analysis. Persons with similar symptoms in the patient's family were included in the genetic screening. The same disease was detected in 1 sister and 2 brothers. The arthroscopic repair was planned for 2 years later, this time after similar complaints on the right side of the patient and medial meniscal tear on MRI. Arthroscopic examination of the right knee joint revealed black meniscus and cartilage degeneration again. A partial meniscectomy was performed on the patient's meniscus flap tear.
Few reports of arthroscopic diagnosis and treatment of ochronosis have been found in the literature. An alkaptonuria was diagnosed as a result of our arthroscopic surgery and postoperative investigations. Genetic counseling was started for this disease, which the family did not realize until now.
