Slipped Distal Femoral Epiphysis in Congenital Insensitivity to Pain

INTRODUCTION Congenital insensitivity to pain (CIP) is a rare disorder, and often presents to an orthopaedic surgeon as recurrent fractures, dislocations, pseudoarthrosis, osteomyelitis etc. Here, we report a case of congenital insensitivity to pain presenting with distal femoral physeal separation in a child. CASE REPORT A 12-year-old girl child came with complaints of limp while walking and swelling in the left knee for past 5 weeks. Mother gave a history that the girl is a known case of congenital insensitivity to pain with clear history of no pain on intramuscular injection since birth. She was born of consanguineous marriage and had no significant trauma, fever, other joint involvement or any features of rheumatism. On local examination, she had no bony tenderness, mild warmth, and moderate knee effusion with restricted range of movement. Plain radiograph showed epiphysiolysis of distal femur with widening of physis. Examination under anaesthesia demonstrated gross movement indicating lower femoral physeal separation. This unstable distal femoral epiphysis was treated under general anaesthesia with closed reduction, percutaneous cross pinning and above knee plaster cast. CONCLUSION Congenital insensitivity to pain (CIP) is a rare disorder to diagnose. Emphasis is given on early diagnosis of orthopaedic problems and prompt treatment, educating parents and prevention of accidents. Physeal separation without significant trauma must prompt an orthopaedic surgeon to think about congenital insensitivity to pain as a differential diagnosis.