Intraoperative determination of the risky angles and safe distances for preventing deep femoral artery injury during proximal femoral nailing for hip fractures in Asian people.

Objective: During proximal femoral nailing, deep femoral artery injury, a rare condition, is often missed and found late, leading to intractable complications such as false aneurysm, hematoma, and anemia. We aimed to determine the novel indicators of the high-risk vertical range and axial angle for deep femoral artery injury that can be easily confirmed intraoperatively using fluoroscopy for hip fracture.

Methods: In a single hospital, the lower extremity computed tomography angiographies of 88 patients (50 men and 38 women) were analyzed. A reference plane was defined as the femoral neck and shaft on the same straight line in the lateral view. Reference points were the lower end of the lesser trochanter and distal femur at 140 mm from the tip of the greater trochanter. To determine the high-risk angle for deep femoral artery injury based on the reference plane, the angle from the reference plane to the deep femoral artery (bone-arterial angle) and the shortest distance between the surfaces of the femur and the deep femoral artery (bone-artery distance) were measured at the lesser trochanter and the greater trochanter. We analyzed the bone-arterial angle and bone-artery distance values, their differences among the sexes, and their correlation with body height and body weight.

Results: Overall, in the lesser trochanter, the mean bone-arterial angle and bone-artery distance were 19.2° ± 8.0° and 22.9 ± 4.7 mm, respectively. In the greater trochanter, the mean bone-arterial angle and bone-artery distance were -33.9° ± 17.0° and 11.3 ± 4.1 mm, respectively. The mean bone-artery distance of the lesser trochanter was significantly longer in men than in women (24.1 ± 4.5 mm and 21.4 ± 4.5 mm, respectively, P < 0.01), and for the lesser trochanter, positive correlations were found between body height and both bone- arterial angle and bone-artery distance (r=0.373, P < 0.001; and r=0.456, P < 0.0001, respectively), with body weight and bone-artery distance positively correlated (r=0.367, P < 0.001). At the greater trochanter, there were negative correlations between body height and bone-arterial angle (r=-0.5671, P < 0.0001), body weight, and bone-arterial angle (r=-0.338, P < 0.01).

Conclusion: The knowledge of our reference plane and high-risk angles and distances allows surgeons to minimize the risk of deep femoral artery injury. These are easily confirmed intraoperatively using fluoroscopy, allowing surgeons to avoid maneuvering in the deep femoral artery range.

Level of evidence: Level IV, Diagnostic Study.