Biomechanical investigation of dynamic hip screw and wire fixation on an unstable intertrochanteric fracture

Abstract

Background Although use of a dynamic hip screw (DHS) for stable intertrochanteric hip fracture fixation has been successfully applied in fracture healing for more than 20 years, DHS fixation on unstable intertrochanteric fractures still has a high failure rate, especially in patients with osteoporosis. Although the wire fixation is usually incorporated with orthopedic device to treat fracture, the wiring techniques are developed through experiences. Thus, this study is objective to investigate the biomechanical property of different wire fixation methods incorporated with DHS system to provide the lesser trochanter fragment stable fixation on osteoporotic TypeA2.1 fracture for enhancing stability after bone reduction. Results Sawbone testing results demonstrated higher maximum load, stiffness, and energy in a DHS with wire fixation compared with DHS fixation only. In static biomechanical testing of a cadaver femur, we compared the stiffness of five fixation models and then tested a fatigue failure model in cycle loading with DHS fixation only. Wiring fixation can enhance stability and the cut-out failure model in the fatigue test was identical to the clinical failure model. Conclusions Lesser trochanteric fragment fixation is a crucial concern in the stability of an A2.1 unstable fracture, and the combination of a wiring technique with a DHS seems beneficial for achieving better stability. The addition of an antirotational greater trochanter is likely to enhance stability through wiring of the greater trochanter.

The impact of the union of lesser trochanter fragments after intramedullary fixation of trochanteric femoral fractures: an X-ray based study

“…In this study, the incidence of postoperative complications in the nonunion group was significantly higher than in the union group, especially for mechanical complications. The importance of the LT-fragment in the stability of proximal femur fractures has been adequately confirmed by biomechanical studies [ 11 , 13 ]. The union of the LT-fragment, which represents the integrity of the medial cortex, might be strongly associated with the stability of intertrochanteric fractures.…”

“…Intertrochanteric fractures commonly occur in older adults, and more than 50% of the cases are associated with a complete fracture of the LT [ 23 ]. Several studies demonstrated that the LT, as a major part of posteromedial construction, plays a significant role in the stability of unstable osteoporotic intertrochanteric fractures [ 10 – 13 ]. Moreover, a biomechanical study showed that the stability decreased gradually with the increasing size of the LT-fragment [ 10 ].…”

Biomechanical study of extramedullary and intramedullary fixation in the treatment of unstable intertrochanteric reversed-tilt fractures of the femur

“…Due to high disability and lethality rate, the treatment of such fracture needs early surgery. The purpose of the operation is: (I) to reduce the pain; (II) to enable the patient to recover as soon as possible; (III) to reduce the complications caused by long-term bed (15). Although a variety of implantable internal materials have been developed, none is available for all types of fracture.…”

Selection of internal fixation method for femoral intertrochanteric fractures using a finite element method

“…Therefore, destruction of the posterior medial side means that the fracture can easily collapse due to axial load, which may cause hip varus. Some studies have shown that reconstruction of the posterior medial cortex can promote fracture healing and reduce postoperative complications[ 7 ]. Gotfried[ 8 ] first proposed the “lateral wall” concept through retrospective research and pointed out that the lateral wall should be paid attention to in surgery.…”