Ochronotic arthritis and ochronotic Achilles tendon rupture in alkaptonuria

Abstract

Introduction: Alkaptonuria (AKU) is a rare disease caused by deficiency of homogentisate 1,2-dioxygenase which results in deposition of homogentisic acid (HGA). Ochronotic arthritis, the deposition of excess oxidized HGA in the connective tissues, causes pigmentation and degeneration of the joint tissues ultimately resulting in chronic inflammation and osteoarthritis. The ochronotic arthritis has similar clinical features with osteoarthritis. There is currently no specific treatment for AKU and management is usually symptomatic. In severe cases, total joint arthroplasty is the major treatment approaches. It is rarely reported in China. Patient concerns: Here we reported a case of a patient with bilateral knee pain for more than 1 year. He complained of a 20-year history of chronic, nonspecific low back pain and stiffness. His urine was black since he was a child. Six years after the knee surgery, his Achilles tendon ruptured. Diagnosis: Specific radiographic and magnetic resonance imaging manifestations were observed. Darkly pigmented full-thickness cartilage and subchondral bone were found during the operation. Histological investigation also manifested dark stains in meniscus and synovial tissues. Black-denatured tendon tissue was also found during the operation. The patient was diagnosed as AKU. Interventions: Total knee arthroplasty and Achilles tendon repair were operated separately after the disease was diagnosed. Outcomes: The patient recovered very well after the second surgery. He returned to full activities, described no knee pain, and presented to the clinic walking without any aid. Physical examination revealed 0 to 20 of plantar flexion and 0 to 15 of dorsiflexion of the ankle. Conclusions: Ochronosis is a very rare disease in Asia. This paper supplies new information for study of this disease. The mechanism is still unknown right now. Further studies will be necessary.

Hip and knee replacement in patients with ochronosis: Clinical experience and literature review

“…These deposits form plaques in the tissue that lead to the characteristic color of this disease, such as the dark color of the sclera, 3 ear and nose cartilage. The deposits can make the connective tissues rigid and usually lead to joint degeneration in the axial and appendicular skeleton by the fourth decade of life, termed "ochronotic arthropathy", 1 particularly hyaline cartilage and intervertebral discs and moreover it can determine, 4 even if rarely, the rupture of the tendons like the Achilles tendon as reported by Baca et al, Jiang et al and Wu et al [5][6][7] Initially Alkaptonuria could manifest itself with a darkening colour of urine due to the presence of homogentisic acid. 8 The disease can also present the involvement of other systems, such as the cardiovascular system with valvulopathies and rarely coronary artery disease, as reported by Couto et al, Cetinus et al and Planinc et al So there are three major features in this disease: presence of HGA in the urine, ochronosis (presence of bluish-black pigmentation in connective tissue) and arthritis of the spine and larger joints.…”

Identification of Potential Inhibitors for the Treatment of Alkaptonuria Using an Integrated In Silico Computational Strategy

“…Moreover, the patients also suffer from knee and backbone pain that originates gradually in two to three decades [ 12 ]. Additional manifestations of AKU include arthritis, aortic stenosis, joint damage, musculoskeletal tears, renal stones, and calcification of the vascular system [ 8 , 13 , 14 , 15 ]. The destruction of joints in AKU is attributed to the alterations in extracellular matrix, deterioration of collagen fibers and loss of proteoglycans [ 2 , 16 ].…”

Reverse Total Shoulder Arthroplasty in Alkaptonuric Shoulder: Case Presentation, Review of Literature, and Technical Considerations

“…Around the age of forty, tissue ochronosis, kidney and prostate stones, and tendon ruptures develop. 14 These changes are caused by a single gene defect and cause malfunctioning or inactive homogentisate 1.2-dioxygenase (HGD), which is one of the main enzymes in tyrosine metabolism and is needed to break down homogentisic acid (HGA). 15 When HGA cannot be converted into maleylacetoacetic acid and thus cannot be excreted, it causes elevated levels and the accumulation of HGA in the body.…”