Which combination of tests is commonly ordered when evaluating a child with suspected hip pathology?

• A. Hip X-ray, CBC, ESR
• B. Hip and knee X-ray
• C. MRI of the hip
• D. Ultrasound of the hip

Answer: (A)

In children with suspected hip problems, the best initial workup combines imaging that looks at the bones and joint with blood tests that screen for infection or inflammation. A hip X-ray is the cornerstone imaging study because it reveals bone quality, growth plate status, and acute or chronic problems such as dislocation, Perthes disease, fractures, or slipped capital femoral epiphysis. At the same time, CBC and ESR help distinguish infectious or inflammatory causes (like septic arthritis or osteomyelitis) from non-infectious hip conditions. Septic arthritis is an emergency, and an elevated ESR (often with compatible signs) plus other lab abnormalities heightens concern and drives urgent management, including joint aspiration and antibiotics.

Ultrasound can detect a hip effusion and guide aspiration, but it doesn’t assess the bone, and MRI, while detailed, is usually reserved for unclear cases or when soft tissue and marrow detail is needed after initial imaging. Knee radiographs aren’t routinely needed unless there’s concern for a process involving multiple joints or referred symptoms. Thus, pairing a hip X-ray with CBC and ESR represents the most practical, broad initial evaluation.