A 6-month-old baby boy was brought to the emergency room with a swollen left leg for the past 3 days. His father stated he was changing his diaper on a changing table and the infant began moving and was about to fall off the table. To prevent the fall, his father held his leg. Afterwards, he noticed that the baby had decreased movement, pain and swelling of his left leg. His physical examination showed a tender and swollen left leg. He had radiologic evaluation of his left leg. X-rays of the femur are shown in the following images (Images 80a and 80b). https://s3-euw1-ap-pe-df-pch-content-public-u.s3.eu-west-1.amazonaws.com/9780429170423/236ca68c-f283-4df8-88b2-3b8ff49bccc9/content/fig80a.jpg" xmlns:xlink="https://www.w3.org/1999/xlink"/> https://s3-euw1-ap-pe-df-pch-content-public-u.s3.eu-west-1.amazonaws.com/9780429170423/236ca68c-f283-4df8-88b2-3b8ff49bccc9/content/fig80b.jpg" xmlns:xlink="https://www.w3.org/1999/xlink"/>
What injury do you see in the radiology images?
Is the injury consistent with the history provided?
Would you recommend any additional imaging or laboratory workup for this infant?
The images show plain x-rays of the left femur. They depict a complete oblique fracture of the proximal shaft of the femur with superimposition of the distal segment with lateral and anterior displacement. A large amount of soft tissue oedema is also seen overlying the fracture site.
This infant is able developmentally to roll and fall off the changing table. However his father holding his leg to prevent his fall is not consistent with the resulting femoral fracture. The oblique nature of the fracture implies torsional loading (twisting or rotation). Femur fractures are the most common paediatric orthopaedic injury requiring hospitalization and the second most common diaphyseal fracture in children. As with all childhood fractures, it is essential to differentiate accidental from abusive fractures. Helpful details include the medical history, the child’s age and developmental stage, an understanding of the mechanism that causes the particular type of fracture and the type, location and age of the fracture. 1–3
In non-ambulating children, 60%–70% of femoral fractures are caused by abuse. Child abuse was suspected as the likely aetiology of this infant’s fracture based on his age, inconsistent history and delay in seeking medical care. The hospital child protection team was consulted and a thorough evaluation for other injuries was conducted. His skeletal survey revealed multiple healing posterior rib fractures which are highly specific for child abuse. Blood was drawn for a complete blood count and liver enzymes that were elevated. Due to the elevated liver enzymes, an abdominal CT scan was done which revealed a liver contusion. His head MRI scan was normal. The combination of fractures and abdominal injuries supported the diagnosis of child physical abuse that was made in this case.