The Determination of Optimal Entry Point for Proximal Femoral Nail Antirotation-II by Fluoroscopic Simulation: A Cadaveric Study

ABSTRACT

PURPOSE: This study seeks to determine the anatomically optimal entry point of proximal femoral nail antirotation-II (PFNA-II®) according to geographic features of Korean cadaveric femoral trochanters for successful reduction of osteoporotic proximal femoral fractures. MATERIALS AND METHODS: Forty-three adult cadaveric femurs without previous fractures or surgeries were included. Anteroposterior (AP) and lateral images of all femurs and PFNA-II® were taken with an image intensifier. Using the image synthesis process via the image editing program (Adobe Photoshop CS6), the optimal entry point was verified and compared with the tip of the greater trochanter (GT) and the cervicotro-chanteric junction on AP images, as well as the width of the trochanter and the neck on lateral images. RESULTS: The optimal entry point of PFNA-II® was an average distance of 9.1 mm (range, 7–15 mm) medially from the tip of GT on AP images. The center of the nail was located at an average of 30% (range, 21%–44%) area from the posterior margin of the middle neck, which is an average area of 38% (range, 26%–48%) from the posterior cortex of the trochanter on lateral images. Furthermore, the ideal entry point was at the extended line of the cervico-trochanteric junction. CONCLUSION: The optimal entry point, which was found to be medial to the tip of the GT and posterior to the center of the middle femoral neck and the trochanter, was at on the extended line of the cervicotrochanteric junction.