In malunion cases, restoration of anatomy is a key factor in obtaining a good functional outcome, but this can be technically very challenging.Three-dimensional printed bone models can further improve understanding of the malunion pattern.The use of three-dimensional (3D) computer planning, and the assembly of patient-specific instruments and implants, especially in complex deformities of the upper limb, allow accurate correction while reducing operation time, blood loss volume and radiation exposure during surgery.One of the major disadvantages of the 3D technique is the additional cost because it requires specific computer software, a dedicated clinical engineer, and a 3D printer.Further technical developments and clinical investigations are necessary to better define the added value and cost/benefit relationship of 3D in the treatment of complex fractures, non-unions, and malunions. Cite this article: 2019;4 DOI: 10.1302/2058-5241.4.180074.