In this paper the Authors report the results gained after the treatment of paediatric idiopathic flat foot by means of Pisani's talocalcaneal arthroerisis and arthroerisis with Giannini's endo-orthotic implant. Two groups of patients have been treated according to the two techniques. According to clinical, radiographic and functional tests, the Authors believe that both the techniques can offer good results to correct idiopathic flat foot of childhood and they highlight the lower invasivity and less damage for the structures of sinus tarsi when Pisani's talocalcaneal arthroerisis is applied.