We appraised whether deformity of the inferior limbs, routinely treated with external fixation (EF), can be corrected when synthesis with locked intramedullary nails is associated with the synthesis and what the indications are.

In all, 24 patients with a deformity of the inferior limbs treated between 1997 and 2003 were included in the study and divided into two groups: (1) patients with external fixation, average 23 years, deformity axial 20° (9–28°); and (2) patients with osteotomy and interlocked nailing. average 35 years, deformity axial 16° (10–25°). The indications for treatment with interlocked nail were set according to the following criteria: (a) possibility to correct the deformity with only restoration of the anatomical axis without necessity of lengthening; (b) previous use of EF; (c) EF refused by the patient, and (d) physeal closure.

In both groups complete correction of the deformity was achieved. In the group of patients treated with EF the time of consolidation was on average 5.5 months (range 4–8 months). In this group the time of consolidation proportionally increased to time required to effect a bone lengthening.

In the group of patients treated with osteotomy and nailing the times of consolidation were different with respect to age, to the side and the type of osteotomy and to the type of deformity. The time of consolidation was 7 months (range 3–12 months). The most rapid consolidation corresponds to the congenital deformities treated with oblique osteotomy.

Correction of deformities by osteotomy and interlocked nail introduces the advantage of not limiting joints and immediate correction of the angular and rotatory deformity. The indication for this technique is that there is no residual hypometry. In this case the treatment of choice is corticotomy and external fixation.