Direct repair of the chronic ochronotic Achilles tendon rupture: a case report.

Background: Alkaptonuria (AKU) is a rare hereditary disease. Ochronotic arthropathy, tendinopathy, and osteopenia/osteoporosis are generally musculoskeletal manifestations in patients with AKU. Because of the ochronotic tendinopathy and osteopenia, the surgical strategy for chronic ochronotic Achilles tendon rupture may be challenging. No studies have reported the surgical treatment of chronic Achilles tendon rupture in patients with AKU.

Case Presentation: We report a case of AKU that required surgical treatment for chronic Achilles tendon rupture. A 60-year-old woman was referred to our department for the assessment of left hindfoot pain that persisted for more than nine months after an ankle sprain. Three years prior to the first presentation to our hospital, she was diagnosed with AKU due to pigmented hip cartilage at the time of total hip arthroplasty. The patient was diagnosed as chronic Achilles tendon rupture based on the results of physical examination and magnetic resonance imaging (MRI). The MRI showed enlarged scar tissue of the Achilles tendon with an intrasubstance high signal intensity. We performed resection of the central part of the scar tissue (total length, 24 mm) followed by direct repair using the proximal and distal stumps of the scar tissue. The MRI at 12months after surgery showed continuity of the repaired Achilles tendon. At 18 months after surgery, the Achilles Tendon Total Rupture Score improved from 22 points preoperatively to 84 points postoperatively. The foot and ankle outcome score also improved.

Conclusions: We reported a case of AKU with chronic Achilles tendon rupture in which direct repair using scar tissue between the tendon stumps was effective. Careful selection of the surgical procedure for the treatment of chronic ochronotic Achilles tendon rupture is recommended because of concomitant ochronotic tendinopathy and osteopenia/osteoporosis.