Backout of the helical blade of proximal femoral nail antirotation and accompanying fracture nonunion.

This article describes a case of backout of the helical blade, a rare complication of proximal femoral nail antirotation. A 31-year-old man had sustained a trochanteric fracture of his right femur. Fracture fixation using proximal femoral nail antirotation and autologous bone grafting 7 months later were performed at another hospital. However, bony union was not obtained, and the patient's pain and limp persisted. Therefore, he presented to the current authors. A radiograph taken at presentation revealed backout of the helical blade and fracture nonunion. A radiograph taken 1 month later showed a more advanced backout of the helical blade. The authors performed exchange nailing supplemented with transplantation of peripheral blood CD34-positive cells and autologous bone grafting. The proximal femoral nail antirotation was revised to a long gamma 3 nail, and a U-lag screw was used to obtain better stability. The postoperative course was uneventful. The patient regained ambulation without pain or support at 12 weeks postoperatively. Radiographic bony union was completed 9 months postoperatively. At 1-year follow-up, he could run and stand on the previously injured leg and had returned to work. Backout of the helical blade should be considered as a possible complication of proximal femoral nail antirotation. Incomplete fixation of the helical blade is the possible reason for backout. The use of a helical blade in young patients may cause difficulty in insertion and result in incomplete fixation.