July 9, 2014
During her residency rotation, pediatric emergency medicine physician Leticia Manning Ryan was surprised to see so many fractures. One patient in particular, a 1-year-old with a distal femur fracture, proved to be a careershaping case. As Ryan was presenting her patient, the attending held up a hard copy of the child’s X-ray and made a secondary diagnosis—rickets—pointing to some bowing, osteopenia and metaphyseal fraying consistent with the condition. Later, Ryan included the image in a research project to evaluate the ability of pediatric residents to diagnose fractures.
“Interestingly, this case stumped both the residents and the attendings, with only 15 percent of each picking up on the rickets,” Ryan says. “We felt this serves as a reminder to evaluate appropriately for non-traumatic medical etiologies of fractures.”
The case also made her wonder what happens to children with fractures in which the underlying cause is not recognized— and also how suboptimal bone health may contribute to fractures in children. Her curiosity ignited a series of retrospective studies on the relationship between bone health and pediatric fractures, with a focus on forearm fractures, which account for 25 percent of all pediatric fractures. In her review of 929 consecutive cases of isolated forearm fractures in Washington, D.C., she found that more than a third of the fractures were severe enough to warrant sedation and orthopedic reduction—or realignment—yet more than 50 percent resulted from minor trauma. Indeed, nearly a quarter of the fractures occurred after a fall from standing height (J Trauma 2010 Oct;69).
“I would sometimes see two children of the same gender, similar ages and from the same neighborhood, have comparable minor falls and one would have a fracture and the other would not,” says Ryan. “Why?”
Was bone mineral density (BMD) a factor? Studies in New Zealand and the United States, Ryan says, have shown that otherwise healthy children with forearm fractures have lower BMD than children without forearm fractures.
“While it may not seem earth-shattering that lower bone mineral density is associated with increased fracture risk, I don’t think this association has been fully recognized in children,” says Ryan. “Also, these findings have not been incorporated into our clinical approach to fracture evaluation and management.”
With that goal in mind, Ryan began to investigate the relationship between forearm fractures and vitamin D deficiency in African American children, who may be at significant risk for bone health deficits. Indeed, in her study of 150 otherwise healthy African-American 5-to-9-yearolds, Ryan found that BMD and vitamin D deficiency, as well as overweight status, were all associated with forearm fracture risk (Journal of Pediatric Orthopedics 2010 March;30(2):106-109).
“Our results add to the growing body of evidence suggesting that a forearm fracture is a marker of children with suboptimal bone health in the sense that they have significantly lower BMD than fracture-free peers,” Ryan says.
Next steps, she adds, include unraveling just how lower bone mineral density leads to fractures, designing interventions to improve bone health in these children, and developing a screening protocol to identify children with fractures related to bone health.