Total hip arthroplasty in a patient with congenital insensitivity to pain: a case report

INTRODUCTION Congenital insensitivity to pain, a rare neurological entity, is characterized by varying degrees of sensory loss and autonomic dysfunction. Orthopedic manifestations of congenital insensitivity to pain include delayed diagnosis of fractures, nonunions, malunions, Charcot arthropathy, acro-osteolysis, avascular necrosis, osteomyelitis, heterotopic ossification and joint dislocations. We here report the case of a patient with congenital insensitivity to pain who had multiple lower extremity fractures at varying intervals, the most recent being a femoral neck fracture managed by total hip replacement. To the best of our knowledge, this is the first report of cementless hip arthroplasty in such a patient. CASE PRESENTATION A 37-year-old Caucasian woman was admitted to our hospital complaining of painless swellings in her lower limb and limping. She had been diagnosed with multiple lower extremity fractures at different times. On physical examination, we found multiple perioral mucosal ulcers, shortening of her nails and acro-osteolysis, a prematurely aged facial appearance, undersized skeletal structure, Charcot arthropathy of her right ankle, anosmia, insensitivity to temperature differences and evidence of mild intellectual disability. A right subtrochanteric femur fracture was treated with an intramedullary nail. Eighteen months later, she presented with similar symptoms and we diagnosed a right femoral neck fracture. We removed the nail and performed cementless total right hip arthroplasty. CONCLUSIONS Congenital insensitivity to pain is a rare condition that is associated with severe orthopedic problems. This case report, which will be of particular interest to orthopedic surgeons, presents several difficulties in the management of patients with congenital insensitivity to pain and notes the importance of close follow-up and early recognition of complications. Cementless total hip arthroplasty may be a good therapeutic option for femoral neck fracture in these patients.