Objective: This study aimed to propose treatment protocol and identify patterns of tillaux fractures using three-dimensional (3D) computed tomography (CT) analysis and to describe an effective reduction technique. Methods: Forty-two juvenile patients with tillaux fractures were evaluated with 3D-CT scan for fracture displacement pattern and received surgical treatment. Tillaux fragment was reduced by pushing the superomedial quadrant part of the fragment slightly downward towards the ankle joint from anterolateral to posteromedial through 5-mm skin incisions with mosquito forceps. A 4.0 cannulated screw was subsequently inserted from the anterolateral to the posteromedial side parallel to the ankle joint. We analysed the distance and direction of fracture displacement with 3D-CT before the surgery. Pre-operative and post-operative plain radiographs were evaluated. Results: Pre-operative 3D-CT analysis revealed a common fracture pattern, varus tilt, and external rotation of fragment. We achieved satisfactory reduction with residual fracture gaps less than 2 mm in 42 cases. Two cases had a 13-mm anterior gap that was reduced by mini-open reduction because of periosteal impingement. No significant clinical complications were found. Conclusion: The closed reduction technique developed based on the fracture pattern identified by 3D-CT anatomical analysis is safe and effective in treating tillaux fractures.