Derotational femoral osteotomy technique with locking nail fixation for adolescent femoral antetorsion: surgical technique and preliminary study.

Rotational femoral osteotomies for excessive femoral antetorsion may be considered only for symptomatic adolescents. Our main objective was to describe our femoral osteotomy technique. Preoperative planning was performed clinically and with the EOS imaging system. Percutaneous osteotomy was performed on distal femoral metaphysis under radioscopic control. Fixation was achieved with an antegrade locking nail. Rotation was checked precisely using a specially designed protractor before distal locking. We carried out a prospective pilot study between 2009 and 2010 on six patients (nine procedures). All the patients included presented a symptomatic femoral antetorsion greater than 20°. Clinical parameters including range of hip mobility and femoral antetorsion were measured every 2 months during the first 6 months, and then every year until skeletal maturation was reached. We obtained orthoroentgenograms using the same technique at each follow-up and torsional analysis by EOS 3D Imaging at 6 months. The average correction of the femoral antetorsion was 19.0 ± 4.0° (range, 13-25°). The average time of union was 3 ± 1.2 months (range, 2-6 months). Patients returned to full weight bearing at an average of 2.6 ± 0.4 months (range, 2-4 months). One patient experienced an early secondary displacement in varus for which a reoperation was required. We believe that this technique can accurately achieve derotational femoral osteotomies. A study is ongoing to evaluate the clinical results of this technique including mechanical and cosmetic advantages.