Broken Bones in Infant Mice Realign Spontaneously

What happens to a fractured arm bone in newborn mice? The bone realigns itself, using a previously unknown process of bone growth and muscle contraction. Much is explained in a study published by Cell Press in Developmental Cell including insights into how human infants and other young vertebrates repair their broken bones.

“Evolution has created a robust mechanism of bone regeneration, which may explain how wild animals can survive traumatic bone injuries, ” said senior study author Elazar Zelzer of the Weizmann Institute of Science, to a writer for Medical Press. The researchers found that fractured bone in infant mice realigned itself through substantial movement of bone fragments. This realignment was driven by bone growth “which acted like a mechanical jack to generate the opposing forces required to straighten the two bone fragments, ” the study reported. Zelzer believes that muscle contraction plays a critical role in the repair process.

According to Medical Press, bone is one of the few organs that can regenerate itself. Zelzer notes that while spontaneous regeneration of bone occurs in infants, adult broken bones require stabilization with braces or a cast in order to heal.

Zelzer suspects that a better understanding of regeneration in infants may improve treatment of broken bones in adults. Future treatment protocols, he suggests, may call for shorter periods of rigid immobilization to allow for the participation of muscle force in the healing process.