Purpose <p>to evaluate the effect of a novel controlled dynamization device attached to external circular fixators on bone healing of tibial fractures.</p> Methods <p>this double-blinded randomized clinical trial evaluated 43 patients over 18 years of age with complex tibial pathologies who were treated without (control) or with a 3D-printed controlled dynamization device attached to external fixators. The devices were installed 60 days after fracture fixation surgery and used for 30 days. All patients were clinically and radiographically followed for up to 8 months to evaluate bone healing. At each monthly evaluation, the radiographs were randomized and evaluated by 3 evaluators. The numbers and frequencies of non-consolidated fractures and the time needed for fracture consolidation in each group were compared (<i>p</i> &lt; 0.05).</p> Results <p>the control group presented a significantly higher number of non-consolidated fractures than the group with controlled dynamization (<i>p</i> = 0.027). The mean times for fracture consolidation for the group submitted to controlled dynamization and for the control group were respectively 4.5 and 6 months. The use of the dynamization device resulted in only 5.2% of complications, while the control group showed a complication rate of 16.6%.</p> Conclusion <p>the novel device for controlled dynamization seems effective in treating complex tibial fractures since it significantly shortened the fracture consolidation time by approximately 30 days and reduced the complication rate.</p>