Investigation of the risk of common femoral artery injury with anterior subcutaneous internal fixation in patients with fragility fractures of the pelvis.

INTRODUCTION: The incidence of the fragility fractures of the pelvis (FFPs) has been increasing in recent years. Operative treatment is effective in patients who are unable to ambulate due to pain. Anterior subcutaneous internal fixation (ASIF) is a minimally invasive and stable fixation used to treat the FFPs, with few reported vascular complications. However, we experienced a case in which the rod directly pressed the common femoral artery (CFA).

OBJECTIVES: The purpose of this study was to examine the relationship between the rod position as defined by ASIF and the CFA in the FFPs patients, and between BMI and the rod-to-CFA distance.

MATERIALS AND METHODS: Pelvic measurements were performed in 47 patients with FFPs using trauma CT. We identified the anterior inferior iliac spine (AIIS) on both sides in axial CT images. Next, we performed a simulation study using the CT images, in which the virtual fixation rod was bent according to the shape of the patients' abdomen in the supine position. The shortest rod-to-CFA distance when the virtual rod was positioned directly above the AIIS in the CT image was measured. The correlation between body mass index (BMI) and the rod-to-CFA distance was measured.

RESULTS: The average shortest rod-to-CFA distance was 18.4 ± 11.1 mm, and the simulated rod compressed the CFA in three of the 47 cases (6.4%). A statistically significant positive correlation between BMI and the rod-to-CFA distance was found (r = 0.47, p = 0.001).

CONCLUSIONS: The course of the CFA should be confirmed before ASIF surgery, and if there is danger of compression of the CFA such as in patients with low BMI, the rod-to-AIIS distance should be adjusted to the optimal distance. However, considering the disadvantages, such as decreased stability of the fixation, when adjusting the rod-to-AIIS distance, and skin irritation and abrasion by the rod, ASIF is not recommended in cases in which the rod is close to the CFA.