A fracture refers to the complete or partial break of a bone or cartilage. Fractures can be caused by trauma to the affected area, overuse and conditions that weaken your bones. A fracture can cause pain and limit function of the area. After a trauma, there can be problems with the healing of a bone. A malunion is when a fractured bone does not heal correctly, leaving it deformed or with shortening of the limb. A nonunion fracture is when the bone doesn’t heal properly and causes pain and instability.