This retrospective study has been made on 23 patients with open fractures of the tibia, type III or IV in Byrd's classification. Ten of these patients showed an aggravation of the soft tissue lesions after the initial treatment. At the beginning of our study, 22 patients had already achieved union and 1 had been amputated. All the patients have had a covering by one or several flaps. The analysis of the results concerns different types of fracture: the time interval between the accident and the first covering by flap, the type of the flap, the length of the hospitalization, the complications; the recovery of the function. First covering by flap has been made in the acute phase in 6 cases, in the sub-acute phase in 12 cases and in the chronic phase in 5 cases. The results of the patients covered in the acute phase were better, than those of the patients covered by flap in the sub-acute or the chronic phase. Early covering of the open fractures of the tibia is recommended. A classification of the open fractures, derived from the classification of Byrd is suggested. We included a type "O" for the fractures with potential aggravation. Different types of flap of the leg have been described. Our behaviour in high energy fractures of the tibia is determined by the necessity to look for a potential fracture aggravation and by the intention of an early covering of the open fracture.