This study aims to use 3D printing personalized plate to locate the position in which the K-wires would be drilled to save operation time and decrease the number of times that the K-wires are drilled.

Subtalar arthrodesis is a standard procedure for treating joint injuries in terminal stage. In this study, in order to improve efficacy and shorten the operation time, personalized plate is prepared before surgery. During the surgery, the articular cartilage is scraped, then the fusion joint is reset to the functional position; the 2-2mm Kirschner wires are drilled with the assistance of the personalized plate,then the position of the fusion joint as well as the Kirschner wires are confirmed under the C-arm; lastly, cannulated screws are screwed in along the Kirschner wires for effective fixation.

In the past surgeries without personalized plate, surgeons could only rely on their experience to locate the position for drilling and then confirm under the C-arm. This would prolong the operation time and be more traumatic to the patients. Using 3D printing personalized plate can solve this problem.

The preparation procedure for the personalized plate: firstly, ankle model are established according to the patient's CT scan data, then select modular pieces to prepare the personalized plate, sterilize it for future use. Apply conventional surgical treatment to the subtalar surface, reset the fusion joint to the functional position, and drill 2-2mm Kirschner wires with the guidance of the plate. If the locations of the fusion joint and the Kirschner wires are satisfying under the C-arm inspection, drill the hollow screw for final fixation.

Inclusion Criteria:

• Patients who receive subtalar arthrodesis and consider internal fixation with screws

Exclusion Criteria:

• Patients who receive subtalar arthrodesis but do not consider internal fixation with screws