Preoperative planning for the treatment of nonunions and the correction of malunions of the long bones.
 A detailed analysis of the steps of preoperative planning as employed in our clinic has been presented.
 We have found these techniques to be of great value in anticipating the requirements that must be fulfilled to correct malalignments and obtain healing when the malalignments occur alone or are associated with nonunion.
 Besides helping one to decide where a malalignment is best corrected to anatomically match the normal extremity, tracings aid in allowing the surgeon to appreciate the kinetics of the operative procedure, as well as to define the best methods of stabilizing the resulting correction.
