A nine-year-old caucasian male presents to the ED with his mother after six days of worsening left thigh and knee pain. The mother reports she could not see her pediatrician for two more weeks and decided to come to the ED today due to her child’s worsening pain. Both the child and his mother deny any history of trauma, injury, or recent illness. The boy’s mother reports that he woke up with vague complaints of thigh or knee discomfort six days ago, and that his pain has since increased to a current 8/10. Upon further questioning, the mother recalls a similar episode of vague mild pain in the left leg two months ago, at which time she did not seek medical attention due to the perceived mild nature of the pain.
The child has no significant past medical or surgical history aside from "being on the small side of the growth chart his whole life" per his mother. The child lives at home with his mother and father, and both parents smoke frequently inside the home. Family history is significant for "lots of blood clots" on the maternal side of the family.
On exam, the child appears to be in moderate pain, but in no acute distress. He is awake, alert, and oriented, and displays an antalgic gait. His height and weight are each at the eighth percentile for his age. He is afebrile, and vital signs are all within normal limits. There is no erythema, warmth, swelling, or visible deformity in the lower extremities bilaterally, including all joints. There is mild tenderness to palpation over the left femoroacetabular joint, but none elsewhere. Active and passive ranges of motion are mildly decreased in left hip internal and external rotation, but normal in the right hip and normal bilaterally elsewhere.
A CBC, ESR, and CRP were all within normal limits. The following plain film was obtained:
What is your diagnosis?
American Academy of Emergency Medicine. 2013;4(4) © 2013 American Academy of Emergency Medicine