The authors would like to thank Liliana Draghetti (Donazione Putti, Biblioteche Scientifiche, Rizzoli Orthopaedic Institute), Keith Smith (Task Force, Rizzoli Orthopaedic Institute), Davide Puppini and Linda Accorsi for their help.
All the images reproduced in the present paper are property of “Donazione Putti, Biblioteche Scientifiche” (Rizzoli Orthopaedic Institute, Bologna, Italy) who kindly gave their consent for the use of the images in the present manuscript.
The present paper was supported by the following funds granted to Rizzoli Orthopaedic Institute: “5‰ (5 per mille), anno 2010”.