Mauricio Kfuri1,2, Philipp Lobenhoffer3. 1. Department of Orthopedics, University of Missouri, Columbia, Missouri. 2. Department of Biomechanis, Medicine and Rehabilitation of Locomotor Apparatus, School of Medicine of Ribeirão Preto, SP, Brazil. 3. Department of Orthopaedics, Gelenkchirurgie Orthopädie Hannover, Hannover, Germany.