Purpose of the study: A retrospective series of 40 patients who underwent simultaneous intramedullary nailings for bilateral femoral shaft fractures was analyzed. The aim of our study was to verify that simultaneous nailing without reaming does not increased risk of fat embolism and to assess clinical and radiological outcome.

Material and method: This series included 27 men and 13 women, mean age 27.8 years, who underwent first intention intramedullary nailing between 1986 and February 1999. Thirty-two patients had multiple fractures. Mean ISS was 23 (range 9 to 59). Among the 80 femoral shaft fractures, 15 were open fractures, 3 were associated with sciatic paralysis, and 4 were complicated by an interruption of the femoral vessels. The AO classification was: type A = 44; type B = 25; type C = 11. Mean delay to simultaneous centromedullary nailing was 3.8 days: surgery was performed on the day of arrival for 25 patients. General anesthesia was used in all cases with respiratory assistance (FIO2 = 50 to 100 p. 100). Mean nail diameter was 11.6 (range 10–14). Gurd criteria and PaO2 were followed to assess pulmonary function. Clinical and radiological outcome was assessed using the modified Thorensen criteria.

Results: Preoperatively, PaO2 was < 87 mmHg in 8 patients. Four of these patients showed a discrete drop off and three improved well above the normal level. Only one patient experienced an important decrease but did not develop respiratory distress. Among the 32 patients with a normal level preoperatively, PaO2 remained in the normal range in 18, fell to a limit level but below 87 mmHg in 4, and showed a substantial drop off of 46 to 172 mmHg in 10. Two of these 10 patients developed respiratory distress due to fat embolism which was fatal in one case. One other patient died in the immediate postoperative period of an undetermined cause. All of the other patients recovered normal gas levels within a few hours or days. There were four cases of phlebitis, including one with pulmonary embolism, one case of respiratory distress by pulmonary superinfection, and one case of septicemia. Both femoral fracture sites became infected in one patient. Malunion occurred in two cases. Two vascular repairs of the femoropopliteal axis were unsuccessful, leading to above knee amputations. Thirty-four patients have been examined after a minimal 12 months follow-up (mean 30 months). Outcome was excellent for 48 femurs, good for 10 and fair for 10.

Discussion: This continuous series of simultaneous bilateral femoral shaft intramedullary nailings appears to be the only such report to date. The clinical and radiological outcomes were comparable with those achieved in one-side femoral fractures. The risk of fat embolism is inevitable after long bone fractures. Many factors favoring the risk are recognized, the most important being delay to fixation. Reaming creates excessive pressure in the medullary canal and could thus contribute to the risk. The presence of an associated chest trauma is not a formal contraindication if effective hematosis is preserved as evidenced by the blood gases.

Conclusion: Simultaneous nailing of bilateral femoral shaft fractures can be performed if blood gases remain acceptable and minimal reaming is used.