Smart bones curve to protect against fracture

Bones grow curved in response to pressure and strain and these changes can be long-lasting, according to a new study by UCL, the Royal Veterinary College London and the Max Planck Institute. Bones can change their shape throughout our life by regulating bone formation and resorption processes, which is often a response to forces which press, pull and twist the skeleton during everyday movements and exercise. The purpose of this shaping is to limit any risk of fracture. Understanding that a bone's fracture resistance is based on engineering rules which would predict a completely straight shape to be optimal, the research team sought to understand why most of our bones are curved if the goal of these changes in shape is to prevent fracture. Whilst undertaking this study, the team knew that other important questions would likely also be answered, for instance, learning whether the beneficial effects of exercise on our skeletons might be long-lived. Researchers from the RVC used 4D in vivo high-resolution micro-computed tomography and computational methods to monitor shape changes in an entire bone over an extended period after highly controlled exposure to a known force. The team also developed a novel approach to quantify 3D bone formation and resorption surfaces validated by conventional histology and how these relate to local stress in bone tissue caused by physiological force.