Original Article

Radiological assessment of the femoral bowing in Japanese population

¹ Department of Orthopedic Surgery, Graduate School of Medical Science, Kanazawa University, Kanazawa 9208641, Japan
² Department of Orthopedic Surgery, Faculty of Medicine, Sohag University, Sohag 82524, Egypt
³ Department of Orthopedics, Philippine General Hospital, University of the Philippines-Manila, Ermita, Brgy 670 Zone 72, Manila, 1000 Metro Manila, Philippines

^* Corresponding author: ahmedallam200@hotmail.com

Received: 30 July 2015
Accepted: 20 November 2015

Abstract

Introduction: Differences in the magnitude of bowing between races are well-known characteristics of the femur. Asian races have an increased magnitude of femoral bowing but most of the orthopedic implants designed for the femur do not match this exaggerated bowing. We calculated the sagittal and coronal femoral bowing in the Japanese population at different levels of the femur and addressed its surgical significance.

Material and methods: We calculated the sagittal and coronal bowing of 132 Japanese femora using CT scan of the femur. A mathematical calculation of the radius of curvature at proximal, middle, and distal regions of the femur was used to determine the degree of femoral bowing.

Results: Mean sagittal bowing of the femur was 581, 188, and 161 mm for the proximal, middle, and distal thirds of the femur and mean lateral bowing was 528, 5092, and 876 mm, respectively. Mean sagittal and coronal bowing for the whole femur was 175 and 2640 mm, respectively. No correlation was found between age, gender, length of femur, and the degree of bowing.

Conclusion: Our study reveals that femoral bowing in the Japanese population is 175 mm in the sagittal plane and 2640 mm in the coronal plane; these values are greater than the femoral bowing in other ethnic groups studied in the literature.

This may result in varying degrees of mismatch between the western-manufactured femoral intramedullary implants and the Japanese femur. We recommend that orthopedic surgeons to accurately perform preoperative evaluation of the femoral bowing to avoid potential malalignment, rotation, and abnormal stresses between the femur and implant.