Malunion of fracture

This describes a fracture which has united but has done so incorrectly. Types of malunion include overlap and shortening, angulation, rotation and cross-union i.e. union to an adjacent bone. The most common reasons for malunion are poor reduction of the original fracture, poor holding of an originally well reduced fracture, soft tissue contracture, and gradual collapse of the fracture due to comminuted or osteoporotic bone.

The malunion may be apparent clinically, or only on x-ray. The decision as to when to intervene and when to leave alone is often difficult. One must carefully balance the morbidity of the malunion - functional and cosmetic - with the morbidity of operation. Malunion in some bones, for example, the clavicle, is frequently without effect, whereas in others, for example, those which then produce asymmetric loading on large weight bearing joints, the risk of complications such as osteoarthritis favour intervention.