A rare cause of arthropathy: An ochronotic patient with black joints.

INTRODUCTION: Alkaptonuria is an autosomal recessive disorder of metabolism. The pathogenesis of alkaptonuria includes chronic inflammation, degeneration, and eventually osteoarthritis. Ochronotic arthropathy is a rare condition found in patients with alkaptonuria.

PRESENTATION OF CASE: A 60-year-old female presented for evaluation after a 10-year history of low back pain, right hip pain, and bilateral knee pain. A cementless right total hip and a cemented left knee replacement were performed. Intraoperatively, the joint surfaces, neighboring ligaments, and tendons were black with pieces of black cartilage tissue. Histological sections of bone and soft tissue demonstrated classic findings of ochronosis, including multiple pigmented areas, reactive giant cells, and a thickened, inflamed synovium.

DISCUSSION: The management of ochronotic arthropathy in alkaptonuria patients is usually conservative, but replacement surgery is offered for severely affected hip and knee joints. A few reports of the surgical treatment of ochronotic arthropathy have been published. This report describes a case of ochronotic hip and knee arthritis treated with total hip and knee arthroplasties.

CONCLUSION: Joint replacement has excellent outcomes in a patient with significant degenerative arthropathy due to ochronosis.