A 5-year-old boy presents with sudden onset of right hip pain and limping after a viral illness a week prior. He is afebrile and able to bear some weight, though with discomfort. Physical exam reveals limited internal rotation and abduction of the right hip. Plain radiographs of the hip are normal. Laboratory tests show ESR 15 mm/hr and CRP 0.8 mg/dL. What is the most likely diagnosis?
✓ Correct Answer: Option D
Transient synovitis typically follows a viral illness, presents with hip pain and limp in young children, and has normal radiographs and mild or normal inflammatory markers. Septic arthritis would have higher fever and inflammatory markers. SCFE and Legg-Calvé-Perthes are less likely given the age and acute presentation/normal X-rays.