For how long does it usually take to heal bone fracture with the external fixator?

Depnds: Fracture stability created by the external fixator can determine healing time. The fixator can be too rigid or to flexible both delaying the time to union. Healing can be between 6 weeks to 30 weeks.

Most likely as any -: Other modality would take, ie, the healing times depends up on the bone fractured, age of the pt, any major medical conditions, smoking (or exposure to it). Any previous injuries, surgeries, etc. Generally 6-8 weeks in adults for the upper extremity and 10-12 weeks in the lower extremity. For kids half these times, generally speaking. Ex fix is used when there is an open fx, which might take long.