Fig. 1

Preoperative planning process. a The location of 3 to 5 Schanz pins (or K-wires) for connecting fracture fragments was determined by digital simulation. b The number, size, and location of the internal fixation were determined by digital simulation, while ensuring that each Schanz pin (or K-wire) formed a rigid complex with the fracture fragments. c PSI part 1, an instrument used to immobilize the calcaneus after reduction and guide the orientation of the screws, was constructed. d PSI part 2, which was used to guide the placement of the 3 to 5 Schanz pins (or K-wires), restored the calcaneus to its prefracture state with Schanz pins (or K-wires) connecting the fragments