Fourteen of Dunn's operations for slipped upper femoral epiphysis were analysed in their indications and their results in comparison with others series. The open operation of the femoral head is a good method for the chronic highest displacements. The notion of an acute displacement leads us to ask for a previous bone scintigraphy in order to make sure of the integrity of the vascularisation. Thus, there was no complication of necrosis in this surgery, but unfortunately, there were two chondrolysis and one mechanical accident.