Positional difference in deep femoral artery during intramedullary nailing for proximal femoral fractures: a within-subject comparative study

BACKGROUND: We aimed to evaluate the positional changes in the deep femoral artery (DFA) during intramedullary nail surgery. We hypothesized that the femur and DFA may be closer due to the medial compression of the thigh on a traction table during the surgery. METHODS: This within-subject comparative study included 20 patients with femoral trochanteric fracture (five males, 15 females; mean age: 83 ± 10.2) who underwent intramedullary nailing. Procedures were performed by five orthopedic surgeons. We performed computed tomography (CT) scans on the healthy thigh in the neutral and surgical limb positions. In the surgical limb position, we performed CT scans 2 weeks postoperatively in the lateral recumbent position with a simulated groin post-compression. Axial images 135 mm distal to the greater trochanter were reconstructed to evaluate the position of the DFA relative to the femur and the transverse locking screw axis. The distance from the medial femur edge to the DFA, medial soft tissue thickness, and the angle between the screw and the DFA were measured. Statistical analyses were performed to compare these parameters between the two positions. RESULTS: The femur-DFA distance significantly decreased from 19.4 ± 3.5 mm in the neutral position to 12.5 ± 3.6 mm in the surgical position (P < 0.001). Medial soft tissue thickness also significantly reduced from 44.7 ± 15.0 mm to 31.0 ± 12.1 mm (P < 0.001). The two positions had no significant difference in the DFA angle (neutral: -23.1 ± 11.1°, surgical: -20.0 ± 10.6°; P = 0.17). The DFA was consistently positioned posterior to the screw insertion axis. CONCLUSIONS: The surgical position during intramedullary nail insertion significantly reduces the femur-DFA distance and compresses soft tissues, which may increase the risk of DFA injury. Therefore, maintaining the hip joint in a neutral position during transverse locking screw insertion should be considered. Extra caution is warranted for taller patients and males owing to anatomical factors. Future studies should validate these findings and optimize surgical techniques.