[Severe angular deformity of the humerus: unilateral external fixation for correction and bone lengthening].

We report the case of a 10-year-old child who presented a severely deformed upper limb due to post-traumatic partial proximal epiphysiodesis of the humerus. The goal of treatment was to correct the severe angular deformity, prevent recurrence, and lengthen the humerus 6 cm. We used the De Bastiani callotasis method with osteotomy of the humeral shaft and unilateral external fixation (Orthofix LRS). The bony deformations were corrected progressively. Angular correction induced a geometric lengthening sufficient to match the length of the healthy limb. Lengthening index was 22.7 days/cm. The functional and esthetic results were remarkable. Complementary epiphysiodesis of the proximal physis successfully prevented recurrent deformation.