Fracture of the tibia (shin bone) is one of the most difficult fractures to treat. They have a reputation for being slow to heal and up to 20 per cent of these fractures are not healed five months after being broken. Furthermore, it can be difficult to determine accurately the progress of healing with the result that treatment is continued for too long or stopped too soon, before the fracture has properly healed. The aim of this project is to develop an accurate measurement of fracture healing based on the transmission of sound waves (using ultrasound) along the broken bone. If successful, this technique could be extended to monitor other types of fracture. In addition, the improved understanding of ultrasound measurement of bone quality could benefit the assessment of bone health in osteoporosis.