A-D Radiographic examination and diagnosis of a fracture in the regenerate during treatment. Boy (No 5 in Table 2) with femoral lengthening due to achondroplastic short stature, 5 years old: A) at the day of the removal of the fixator. B) day 0, after removal of the frame, one TEN was inserted due to prophylactic stabilization. C) x-ray at day 50 after removal shows a new callus formation within the regenerate, it must have been a fracture type 1b weeks ago, estimated caused by manipulation during insertion of the TEN, no other reason was applicable. D) 4 months (day 133) after removal of the fixator, before removal of the TEN with bony healing without loose of length or development of further malformation. E) late follow up, 1 year after removal of the TEN.