Malunions of the tubular bones of the hand should be carefully studied to understand the original deforming forces at the time of injury. Once a three-dimensional concept of the deformity is embraced, a careful plan for osteotomy can be developed and executed. Surgical approach must afford adequate access with the least possible injury to soft tissues. Technique of osteotomy must be tailored to the configuration, location, and biomechanical requirements for proper realignment of the malunited fracture. Important principles in the management of metacarpal and phalangeal malunions are: 1. Rotatory deformities are most disabling yet frequently not appreciated. A 10-degree rotational malalignment in the metacarpal results in a 2-cm overlap at the finger tip. Alignment should always be checked with the fingers flexed into the palm. 2. Adherence to biomechanical principles of fracture repair is mandatory. 3. The appropriate form of osteotomy and subsequent fixation must be carefully chosen and applied to each individual deformity. Familiarity with the osteotomy techniques and alternative forms of fixation affords flexibility in managing complex deformities. 4. The presence of malunion suggests the presence of fracture disease in the soft tissues. They must be delicately handled and carefully inspected for the presence of scarring, adhesions, and contractures. Careful protection of delicate structures should be complemented by judicious tenolysis and arthrolysis at the time of osteotomy. 5. Appropriate, functional postoperative rehabilitation is mandatory. Without adequate therapy the best surgery will produce suboptimal results. Adherence to these principles can avoid further complications and problems and provide a successful ultimate outcome.