The authors present a comparative review of cases concerning the results obtained in the treatment of idiopathic flat foot: the methods compared were Castaman exosinotarsal arthrorisis and Giannini endosinotarsal arthrorisis. Between 1990 and 1198 a total of 80 patients, of which 40 with calcaneo-stop, and 40 with Giannini screws, were submitted to surgery at the Orthopaedic and Traumatology Department of the University of Rome "La Sapienza". The clinical, radiographic and functional results were classified as good, fair and poor. The authors agree on the effectiveness of both methods based on the results obtained and the facility of implantation techniques, however emphasizing the minor injury of the anatomical structures of the subtalar joint when the calcaneo-stop method with Castaman conical screws was used.