Abstract— At first, the doctors mentioned their own medical experience with treatment of complex pelvic injury in patients with polytrauma and give reasons for necessity of early stabilization of pelvic fractures by means of external fixation, especially with continuous hemorrhage into lesser pelvis region and the retroperitoneum. Afterwards they used damage control surgery methods including selective embolization. However, this article is focused also on the design of external fixators applied in traumatology and orthopaedics (i.e skills of engineers). These fixators can be used in the treatment of open and unstable (i.e. complicated) fractures of pelvis and its acetabulum. Two versions (i.e. old and new) are compared. Numerical modelling (i.e. Finite Element Method), together with CAD modelling, experiments, material engineering, and nanotechnology are presented as a support for developing of a new design of external fixators. Keywords—traumatology, pelvis, complex injuries, polytrauma, acetabulum, fractures, design, biomechanics, numerical modeling I. INTRODUCTION NCREASING number of high-energy injuries brings increase in number of complex injuries of the pelvis, where apart from fractures of the pelvic girdle also arteries, nerves, soft tissues and pelvic intraperitoneal and retroperitoneal organs are injured. The most severe complication of these injuries consists in extensive hemorrhage, mainly from injured skeleton, a presacral Assoc. Prof. M.Sc. Karel FRYDRÝŠEK, Ph.D., ING-PAED IGIP, Department of Mechanics of Materials, Faculty of Mechanical Engineering, VŠB – Technical University of Ostrava, 17. listopadu 15/2172, 708 33 Ostrava, Czech Republic (phone: +420 597323495, e- mail: karel.frydrysek@vsb.cz). Assoc. prof., M.D. Leopold PLEVA, Ph.D., Trauma Centre, University Hospital in Ostrava, 17. listopadu 1790, 708 52, Ostrava, Czech Republic (e-mail: leopold.pleva@fno.cz). M.Sc. Jaroslav JOŘENEK; Department of Mechanics of Materials; Faculty of Mechanical Engineering, VŠB - Technical University of Ostrava, 17. listopadu 15/2172, 708 33 Ostrava, Czech Republic (e- mail: jaroslav.jorenek.st@vsb.cz). M.D. Vladimír JEČMÍNEK, Ph.D., Trauma Centre, University Hospital in Ostrava, 17. listopadu 1790, 708 52, Ostrava, Czech Republic (e-mail: vladimir.jecminek@fno.cz). M.Sc. Richard KLUČKA, Department of Mechanics of Materials, Faculty of Mechanical Engineering, VŠB – Technical University of Ostrava, 17. listopadu 15/2172, 708 33 Ostrava, Czech Republic (e- mail: richard.klucka@seznam.cz). M.Sc. Milan SIVERA, Department of Mechanics of Materials, Faculty of Mechanical Engineering, VŠB – Technical University of Ostrava, 17. listopadu 15/2172, 708 33 Ostrava, Czech Republic (e- mail: sivera.milan@email.cz). and paravesical vascular plexes that can directly threaten life of the injured child by hemorrhagic traumatic shock. Diagnostic methods, apart from RTG pelvic, are ultrasonography, computer tomography and computed angiotomography, see [1]. The basis for the treatment of instable pelvic fractures consists of pelvic skeleton stabilization, which in the urgent stage is ensured by application of a pelvic clamp with subsequent application of external fixator, see [1] − [4], [7] − [12] and Fig. 1. Fig. 1 Complex pelvis fracture treated with external fixator (Trauma Centre, University Hospital in Ostrava, Ostrava, Czech Republic) In case of continuous hemorrhage, we perform urgent AG with surgical treatment of injured arteries or their selective embolization, see [5]. In extensive devastating injuries we do not hesitate to perform tamponade of the pelvis with possible bilateral ligature of a. iliaca interna, see [6]. II. EXTERNAL FIXATORS However, this article reports about the designing of external fixators applied in traumatology and orthopaedics. This work was performed by VŠB – Technical University of Ostrava together with University Hospital in Ostrava and company MEDIN a.s. (Czech Republic), see web page [9] and [10] (i.e. work of the project External Fixation, see Fig. 2 and 3). New External Fixators for Treatment of Pelvis and Acetabulum Fractures K. Frydrýšek, L. Pleva, J. Jořenek, V. Ječmínek, R. Klučka, M. Sivera I INTERNATIONAL JOURNAL OF BIOLOGY AND BIOMEDICAL ENGINEERING Issue 2, Volume 7, 2013 36