Remodelling in Children's Fractures and Limits of Acceptability

Remodeling follows inflammatory and reparative phases of bone healing and is very pronounced in children. Unlike adults, in growing children, remodeling can restore the alignment of initially malunited fractures to a certain extent, making anatomic reduction less essential. Remodeling is not universal and ubiquitous. Animal experiments and clinical studies have proven that in a malunited fracture, the angulation corrects maximally by physeal realignment (75%) and partly by appositional remodeling of the diaphysis also known as the cortical drift (25%). Remodeling potential reduces with the increasing age of the child; lower extremities have higher remodeling potential compared to the upper extremity. Remodeling is most pronounced at the growing end of the bone and in the axis of the adjacent joint motion. Correction of a very small amount of rotational malalignment is possible, but it is clinically not relevant. Overgrowth of the bone after a fracture occurs due to hyperaemia of fracture healing. Overgrowth is the most common after paediatric femur fractures, though it is reported after fractures of the tibia and humerus as well. The orthopaedic surgeon treating children's fractures should be familiar with regional variations of remodeling and limits of acceptance of angulation in different regions. Acceptability criteria for different bones are though well defined, but serve best as guidelines only. For the final decision-making patient's functional capacity, parents' willingness to wait until the completion of the remodeling process, and the experience of treating doctor should be considered concurrently. In case of the slightest doubt, a more aggressive approach should be taken to achieve a satisfactory result.