Internal fixation of nonunions

Abstract

We review the two major types of internal fixation of nonunions (plating and intramedullary nailing), and analyze nonunions in different locations (upper and lower extremities). Depending on the type and the location of the nonunion, plating or intramedullary nailing may be selected. Both have advantages and disadvantages: plating requires opening the nonunion site, which entails some damage to the soft tissues, and carries with it a risk of secondary infection. With plating, it often is impossible to do a real decortication because the periosteum may be thin and poorly adherent to bone, and the quality of bone may prove insufficient to achieve good fixation with most of the screws. However, plating still is used in metaphyseal nonunions, and angular deformities may be corrected by applying a plate under tension on the convex side of the bone. Nailing can be done percutaneously in numerous cases; it has a smaller risk of infection but, should an infection be present, there is a risk that it may spread over the entire length of the medullary cavity. Nailing stimulates bone formation, but noninterlocking nails may cause shortening and rotational instability of the nonunion site. Plate fixation was popular approximately 20 years ago, but now has been largely superseded by intramedullary nailing except for proximal or distal nonunions. Dynamic locking nails are preferable. Successful treatment of nonunions often requires several consecutive surgical actions and a global strategy must be established from the beginning, taking care not to interfere with the successive steps.