Hospital Arnau de Vilanova 1 article published in JoVE Medicine Three-Dimensional Preoperative Virtual Planning in Derotational Proximal Femoral Osteotomy Caterina Chiappe1, Alejandro Roselló-Añón1, Vicente Sanchis-Alfonso1 1Department of Orthopaedics, Hospital Arnau de Vilanova This work presents a detailed surgical planning protocol using 3D technology with free open-source software. This protocol can be used to correctly quantify femoral anteversion and simulate derotational proximal femoral osteotomy for the treatment of anterior knee pain.