Which option best describes the timing for fixator removal after lengthening in external fixation?

• A. Immediately
• B. After 2-4 times the lengthening duration
• C. After 1 year
• D. After radiographs show complete union

Answer: (D)

The timing for removing an external fixator after lengthening hinges on the consolidation of the lengthened segment. The fixator is kept in place until the new bone (the regenerate) has matured enough to bear loads on its own. Radiographs are the key tool here: you want to see the regenerate showing complete union, with bridging bone across the lengthened area and signs of corticalization, indicating solid bony continuity. Clinically, the limb should feel stable and there should be minimal pain or movement at the regenerate site when tested.

Removing the hardware only after radiographs demonstrate complete union minimizes the risk of refracture or deformity, because the bone has achieved sufficient strength. Waiting only by a fixed time or a protracted period (like a year) does not account for individual healing variability. Early removal—before union—is unsafe, while waiting longer than needed delays rehabilitation without added benefit.