Case 11

You were asked to review x-rays for a 4-month-old girl who had a healing fracture of her right femur (Images 11a and 11b). She was wearing a Pavlik harness. The infant was brought to the emergency room 3 weeks ago on the day after she reportedly fell sideways from a ‘futon’. She was unable to sit without support but was able to roll. Her mother had placed her down briefly to answer her cell phone. Her mother had turned away to answer the phone and she heard the infant hit the carpeted floor and begin to cry. She picked her up and she stopped crying. She did not notice any injury. She fed her a bottle of her regular formula, placed her in her bed, and she fell asleep. She slept well overnight, and the next day she was ‘cranky’ and had trouble feeding. Her mother later brought her to the emergency department when she noticed that her leg appeared swollen. A report to Child Protective Services had not been made.

What do the images show?

What evaluation should be done to assess a differential diagnosis?

How do you assess whether this injury is abuse or accidental?

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26Images 11a and 11b show a healing, complete fracture of the right femur diaphysis, with marked periosteal reaction, periosteal new bone formation, exophytic callus, blurring of the fragment edges and callus joining the bone fragments. This type of healing occurs more frequently when the leg is kept in a harness rather than immobilized in a cast.

Prior x-rays should have been reviewed to understand the initial injury pattern and subsequent healing. Compared with prior images, the fracture has stable medial displacement and mild anteromedial angulation of the fracture fragments with significant increase in periosteal reaction and callus formation along the fracture plane. The initial x-rays demonstrate an acute spiral oblique fracture pattern with no evidence of healing (Images 11c and 11d). One week later, early periosteal new-bone formation and early callus formation are visible (Images 11e and 11f). Given the possibility of inflicted trauma in this presentation, initial and follow-up full imaging of the axial skeleton using a skeletal survey are indicated to identify additional fractures or bone disease. ¹ Serum chemistries for calcium, phosphate, alkaline phosphatase, vitamin D and parathyroid hormone levels can help identify and categorize metabolic bone disease.

To understand the mechanism of injury, you need additional information about the height of the futon, the surface the child landed on, how the child fell and the position she landed in. Did she land on her knee? Why did her mother wait to seek medical care given the complete fracture? Were other adults present when the reported accident occurred? Is there any family history of bone disease or dysplasia? These questions will require additional information from the mother, scene investigation, and involvement of Child Protective Services and possibly law enforcement.