This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Congenital Dislocation of Hip (C.D.H.), Subject name: Orthopaedics
A 10-year-old obese child from endocrinology department was referred to emergency for a painful limp with hip pain which of the following investigation is not required: 
Select and explain. 
A. X-ray of the hip, B. MRI of the hip, C. CT scan of hip, D. USG of hip
C: CT scan of hip
Answer: C: CT scan of hip 
Explanation: (c)This is an Obese Limping child with hip pain the possible differential diagnosis will be Osteomyelitis (X-MAS)Septic arthritis (X-MAS)Slipped capital femoral epiphysis (X-MRI)Transient synovitis (X-MAS)Hence CT will be least preferred. Previously CT Scan was carried out for SCFE but now MRI has replaced its indication.