Objective:To investigate the effect of single butterfly fracture fragment on healing of femoral shaft fracture treated with intramedullary nail.Methods:From February 2010 to February 2016

72 patients with closed femoral comminuted fracture admitted to Lianyungang Hospital of Xuzhou Medical University

including 46 males and 26 females

with an average age of 38（17-64 years old）

40 cases on the right side

and 32 cases on the left side.All patients were treated with femoral interlocking intramedullary nail.According to femoral shaft diameter

the displacement degree of butterfly fracture was divided into four degrees:Ⅰ degree（displacement was less than 1/3 of shaft diameter）:41 cases;Ⅱ degree（displacement was greater than 1/3 of the diameter and less than 2/3）:17 cases;Ⅲ degree（displacement was greater than 2/3 of the diameter）:9 cases; Ⅳ degree（fracture fragment turnover）:5 cases.According to RUSF score

fracture healing rate and average time of fracture healing

the effect of displacement degree of fracture fragment on fracture healing was evaluated.Results:All the indexes of the 4 groups were statistically significant.The fracture healing was best in the group of I degree displacement

with the fracture healing rate of 87.8% and the average healing time of 4.8 months.The patients with Ⅲ degree displacement and Ⅳ degree displacement had the worst healing

and the healing rate was 22.2% and20.0%

respectively

and the average healing time was 12.6 months and 18 months.The patients with Ⅱ degree displacement had the healing rate of 64.7% and the average healing time of 8.9 months.Conclusion:The butterfly fracture with Ⅰ degree displacement need no intervention

the fracture with Ⅳ degree displacement should be restored and as close to the bone defect as possible to avoid nonunion

and Ⅱ degree and Ⅲ degree displaced fragments should be given closed reduction to within Ⅰ degree displacement as far as possible to minimize the incidence of nonunion.