Branch clue to child bone secrets

Fractures in children are often different to those in adults

Children traditionally break their bones falling out of trees, but a scientist says branches hold clues to a particular type of childhood fracture.

The "greenstick fracture" happens when the bone splits lengthwise, rather than cleanly at right angles.

Dr Roland Ennos, from Manchester University, thinks similarities between crystals in young bone and cells in young wood could explain this.

His research is published in the scientific journal Proceedings B.

The way bone structure develops in children and young adults is still not fully understood by scientists.

However, "greenstick fractures" are known to be more common around puberty, when bones are growing quickly.

Dr Ennos suggests that, like the cells in young wood, the bone crystals being deposited in fast-growing young bone are arranged lengthways, before being remodelled so that the crystals point in different directions.

The lengthways arrangement could make them more likely to break along those lines, just as they do in growing sticks of wood, he said.

"Bones are remodelled to stop cracks from developing - the crystals dissolve and are relaid in those places. Children's bones have not had time to do that."

He said that orthopaedic experts might be able to look into the idea further.

Professor Jonathan Tobias, a researcher in child bone health from the University of Bristol, said that the observation was an "interesting concept", although unlikely to have a direct impact on clinical practice.

"People have been looking at the relationship between bone structure and strength for some time, and this looks at it from another direction.

"We are certainly aware that there is an issue between growing bones at puberty and this type of fracture."