Alkaptonuric arthropathy with periprosthetic fracture:a case report

Alkaptonuria or Ochronosis is an autosomal recessive congenital metabolic error due to absence of enzyme homogentisic acid oxidase. Recently, we had an opportunity to diagnose this condition in one of our patients. An old aged man developed a pathological fracture of femur after a trivial fall at home. He was diagnosed to have intracapsular fracture neck of femur. Intraoperatively we noticed blackish discoloration of femoral head which lead us to investigate the case for alkaptonuria. Hemiarthroplasty was done with Austin moore prosthesis. Patient had cutaneous pigmentation and gross arthritic changes at multiple joints including spine. After one and half year patient developed a periprosthetic fracture of the femur for which open reduction and internal fixation was done. A periprosthetic fracture in ochronotic patient has never been reported till date which makes it a rarer entity. This article presents the clinico-radiologic manifestations of the case with surgical management and a follow up of two years.