Abstract—Sideway falls are potential accident to elderly population and very risky for hip fractures. The tragedy may become worst for patients with hip arthroplasties. Sudden impact loading that occurs during fall may lead to femoral fractures and joint failures. Different techniques of falling give different consequences and reflect the long term stability. In this study, risk of bone fractures was predicted during sideway falls using finite element analysis with damage formation criterion. Inhomogeneous model of femur was developed from CT-based data for computational analysis. Femur models with resurfacing hip arthroplasty (RHA) and total hip arthroplasty (THA) were constructed to estimate the fracture possibility in hip arthroplasties. Four different configurations of sideway falls were considered namely FC1, FC2, FC3 and FC4 which presenting different hip loading direction and boundary conditions. Hip impact forces were normalized to body weight (BW) and varies from 1BW to 5BW were applied to each configuration. The results showed that the patterns of bone fractures were different between intact, RHA and THA femurs. Numbers of element failures were highest in RHA femur while lowest in THA femur for almost all configurations. Fractures locations were predicted at trochanteric region due to boundary condition during fall. Indication of fractures inside the canal shaft of THA femur due to bending effects may contribute to prosthesis loosening and instability.

Index Terms—Hip resurfacing, total hip arthroplasty, sideway falls, bone fractures, damage formation.

A. H. Abdullah is with the Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga 816-8580 Japan, on study leave from Faculty of Mechanical Engineering, Universiti Teknologi MARA, Selangor, Malaysia (e-mail: abdul.halim.abdullah.822@s.kyushu-u.ac.jp).
M. Todo is with Research Institute for Applied Mechanics, Kyushu University, Kasuga 816-8580 Japan (e-mail: todo@riam.kyushu-u.ac.jp).
Y. Nakashima and Y. Iwamoto are with the Department of Orthopaedic Surgery, Kyushu University, Fukuoka 812-8582 Japan.

Cite: Abdul Halim Abdullah, Mitsugu Todo, Yasuharu Nakashima, and Yukihide Iwamoto, "Risk of Femoral Bone Fractures in Hip Arthroplasties during Sideway Falls," International Journal of Applied Physics and Mathematics vol. 4, no. 4, pp. 286-289, 2014.