Location of Femoral Vessels Around the Acetabulum in Crowe Type 4 Dysplastic Hips.

Background: There are anatomical differences in the femur and acetabulum on the dysplastic hips. Yet, although there are detailed researches on bony structure differences, studies regarding anatomical differences for the vascular structure are insufficient. The study aimed to determine the relationship between the femoral artery and vein with acetabulum in computed tomography evaluation of Crowe type 4 hips and to compare with normal hip femoral vein and artery anatomic position.

Methods: Forty patients with one side hip Crowe type 4 deformity and opposite side normal hip were found suitable for the study. Pelvis CT was previously applied to all patients for the planning of total hip arthroplasty surgery. Normal hip acetabulum and the true acetabulum of the dysplastic hip were marked with the Ranawat's triangle and were then divided into quarters with four axial slices of the acetabulum; as dome, proximal one-fourth, center, and distal three-fourths. The shortest distance from the femoral vessels to the pelvis was measured at these 4 axial slices at the dysplastic side and compared with the healthy side.

Results: The distance of the vein to the acetabulum is closer to the dysplastic side. At distal three-fourths of Ranawat's triangle axial images, both femoral artery and femoral vein are closer to acetabulum at the dysplastic side.

Conclusion: The analysis of preoperative images in cases of Crowe type 4 hip shows that the femoral vessels are closer to the anterior wall of the dysplastic true acetabulum at the level of the center of the hip (vein, mean: 2.7 mm closer) and below the center of the hip (vein, mean: 3 mm; and artery, mean: 3.3 mm closer) when compared with the normal acetabulum. Anatomic relationships knowledge can be used intraoperatively to avoid iatrogenic vascular injury during Crowe type 4 dysplastic hip arthroplasty surgery.