Case 77

A 10-month-old baby boy presented with pain of his left leg and decreased movement. His mother gave the history of him falling off her bed. She was nursing him in bed and she fell asleep. When she woke up, she found him on the floor next to the bed. He was fine after the fall and continued to sleep and feed well. Later that day, when he was on his ‘bouncy’ seat, he started to bounce and attempted to push on both his legs. He cried when he did that and refused to bear weight on his left leg. On his physical examination, he had a slightly swollen left thigh that was tender. He did not have any other patterned marks or bruises or concerns of physical abuse on exam. X-rays are shown in Images 77a and 77b. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429170423/e1d751c1-a9c7-4bb9-9d59-53742c84031a/content/fig77a.jpg"/> https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429170423/e1d751c1-a9c7-4bb9-9d59-53742c84031a/content/fig77b.jpg"/>

What do the x-rays show?

Is the injury consistent with the provided history?

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His left leg x-ray showed a cortical irregularity at the left femoral distal metaphysis consistent with non-displaced fracture (Images 77a and 77b). Child abuse was suspected due to the infant being immobile and due to the strong correlation of femur fractures with child abuse in this age. A skeletal survey was done that showed no additional fractures. He also had head imaging and a dilated retinal examination both of which were normal. Child Protective Services was notified for further investigation and to assess for any further safety concerns.

The mother described her bed as a mattress on top of a box spring and frame. She stated that the frame sticks out several inches beyond the mattress. It is possible that the child impacted his knee when falling on the frame or the floor. Impacted transverse fracture of the distal femoral metadiaphysis may occur as a result of an accidental short fall of young children. An evaluation for child abuse should still be pursued in these cases, but with an absence of additional skeletal findings and a history of fall, it is likely that an accidental mechanism accounts for the injury. ¹ It was felt that the bouncy seat elicited pain but was not the cause of the fracture. Fractures have been reported as caused by exersaucers, a stationary walker where the infant is seated with the ability to push up and bounce using his feet. However those have a different mechanism and are quite different from the bouncy chair in which the child was seated. ² Upon obtaining history from the mother and reviewing of the chart and discussion with the radiologist, it was determined that it is possible for a fall from the bed with impact to the knee against the frame to result in this fracture. However, due to the fall not being witnessed, we discussed with Child Protective Services that an investigation was needed with home visits and evaluation of other children in the home.