Sasa Milenkovic1, Milan Mitkovic2. 1. University of Nis, Faculty of Medicine, Clinic for Orthopaedic Surgery and Traumatology, University Clinical Centre Nis, Bul. dr Zorana Djindjica 48, 18000, Nis, Serbia. sasaortoped@gmail.com. 2. University of Nis, Faculty of Medicine, Clinic for Orthopaedic Surgery and Traumatology, University Clinical Centre Nis, Bul. dr Zorana Djindjica 48, 18000, Nis, Serbia.