Alkaptonuria is a rare autosomal recessive metabolic disorder. It is characterized by the accumulation of homogentisic acid in the body due to a lack of enzymes that degrade it. Over time, it results in joint degeneration and eventually leads to ochronosis. Ochronosis refers to bluish-black discoloration of connective and other tissues within the body. In this study, we present 5 distinct cases diagnosed with alkaptonuria. They have undergone 8 total joint replacement surgeries (4 hips and 4 knees) within 8 years (2010-2018). All patients had an excellent outcome over several years. The follow-up period ranged from 2 to 10 years. Although none of the presented cases had intraoperative or postoperative adverse sequelae, we must take care when dealing with patients with ochronotic arthropathy. They carry a higher risk of complications than other patients with osteoarthritis disease. These complications include fractures due to fragile bone quality, muscle or tendon rupture, joint instability, and anesthesia-related complications. Total joint arthroplasty is a valid and safe option in the management of hip and knee ochronotic arthropathy.

Alkaptonuria is a rare metabolic disease characterised by accumulative deposition of homogentisic acid in the connective tissue of the body. This results in early degeneration of tendons, cartilages, heart valves, and other tissues. The main objective of the study is to examine the possibility of the nervous system involvement in patients with alkaptonuria The sample consists of two groups; 22 patients with AKU and 20 controls. A neurological assessment has been carried out including detailed medical history, neurological examination, and a nerve conduction study of the nerves of the dominant hand. The prevalence of any abnormality was compared between the two groups using chi square test. The mean values of the nerve conduction study were compared between the two groups using student t-test. There was a higher prevalence of low back pain, hearing problems and tinnitus, numbness and neuropathic pain in alkaptonuria patients. There was no significant difference between the two groups in other conditions such as seizures, headache, and syncope. The values of the nerve conduction study did not show significant difference between the two groups. Neurologically related symptoms in alkaptonuria mostly represent complications of the connective tissue degeneration rather than direct involvement of the nervous system. This has been supported further by the normal findings of the neurophysiology study in patients with alkaptonuria.

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