12th IFToMM World Congress, Besançon (France), June18-21, 2007 Comparative Study of Fixation Devices for Intertrochanteric Fractures C. Sticlaru * A. Davidescu † “Politehnica” University of Timioara “Politehnica” University of Timioara Timioara, România Timioara, România Abstract — The paper presents a comparison of some fixation devices for intertrochanteric fractures. The devices studied are: the fixed plate, the sliding screw-plate device, the intramedullary hip nail and Ender wire. The devices are designed in ProEngineer (ProE). The 3D models were analyzed in Ansys. Different materials are investigated and aspects concerning the stress and strain state, the loading of the contact area between bone fragment and bone – device. Keywords: intertrochanteric fracture, fixation devices, finite element method I. Introduction Hip fractures, particularly in older persons, result in problems that extend far beyond the orthopedic injury, with repercussions in the areas of medicine, rehabilitation, psychiatry, social work, and health care economics. A hip fracture is generally a fracture of the proximal femur. Such injuries are divided into three categories, according to the anatomical area in which they occur (Fig. 1). Femoral-neck fractures are located in the area distal to the femoral head but proximal to the greater and lesser trochanters and are considered intracapsular fractures, because they are located within the capsule of the hip joint. This anatomical characteristic has important implications for healing. Fractures in this area, particularly those involving marked displacement, can disrupt the blood supply to the femoral head and are therefore associated with an increased incidence of healing complications (nonunion and osteonecrosis of the femoral head). Intertrochanteric fractures, which occur in the well- vascularized metaphyseal region between the greater and lesser trochanters, are extracapsular fractures that do not interfere with the blood supply to the proximal femur. These fractures are thus not associated with the healing complications characteristic of femoral-neck fractures. The most common complications of intertrochanteric fractures are mal union and shortening as a result of the deforming forces and compromised bone quality in this area of the proximal femur. Subtrochanteric fractures are those that occur just below the lesser trochanter. Femoral-neck and intertrochanteric fractures account for over 90 percent of hip fractures, _________________________ *E-mail : carmen.sticlaru@mec.upt.ro ‡ E-mail : arjana.davidescu@mec.upt.ro occurring in approximately equal proportions and subtrochanteric fractures account for the remaining 5 to 10 percent [1]. The estimated incidence of hip fractures in the United States is 80 per 100,000 populations [1]. The incidence increases with age, doubling for each decade after 50 years, and is two to three times higher in women than in men. The incidence is two to three times higher in white women than in nonwhite women. Other risk factors for hip fracture include a maternal history of hip fracture, excessive consumption of alcohol and caffeine, physical inactivity, low body weight, tall stature, previous hip fracture, use of certain psychotropic medications, residence in an institution, visual impairment, and dementia [1]. Osteoporosis is an important contributing factor, because it decreases the skeleton’s resistance to injury, and approximately 90 percent of hip fractures in the elderly result from a simple fall. The characteristics of a fall (the direction, site of impact, and protective response) and the habitus are recognized as important factors influencing the risk of hip fracture from a fall.