Derotation osteotomy is the only available treatment for medial femoral torsion in paediatric patients. To eliminate the need for postoperative immobilisation and to allow immediate weight bearing, we suggest a new technique that guides femoral growth. The goal is to convert part of the axial growth into rotation by placing a system composed of two screws and a cable around the distal femoral physis. We used this percutaneous technique to treat 20 knees in 11 children. The preliminary outcomes indicate good efficacy with about 1.2° of derotation per month and a total mean derotation of 25° over 22 months. Postoperative stiffness was the main complication but resolved with physical therapy. This technique may therefore constitute an alternative to derotation osteotomy.