The development of a universal fixator for application in low- and middle income countries

Abstract

In the worlds poorest regions there exists an urgent need for surgical care. Open fractures, one of the Bellwether procedures, are treated in only 42% of the health facilities in low- and middle income countries. Worldwide, external fixation is one of the most important treatment methods for open fractures, providing immobilization to the fracture while retaining soft tissue integrity. In LMICs however, is the treatment of open fractures with an external fixator not self-evident. Due to a lack of equipment and incomplete donations, a clear need is indicated for application of a standardized low-cost external fixator system for LMICs. The goal of this thesis is to develop a universal fixator clamp for application in low - and middle income countries, providing fixation to both lower- as upper extremity open fractures. In collaboration with Global Surgery Amsterdam and the Amsterdam University Medical Centre, the design of a predecessor external fixator clamp is improved. The design of this clamp consists of three sloths: 4mm, 5mm, and 8mm. As a consequence, this reduces the number of components needed to perform external fixation. Included factors in this iterative design process are the identification of needs, serving as input for the prototype development of the universal clamp. Based on the defined needs the product requirements are defined, giving prioritization to cost-effectiveness. These requirements served as input for the next phase of the design process. The conceptualization of the refined universal clamp is guided by three subproblems: stability enhancement, weight reduction, and increasing functionality. A material analysis demonstrates aluminium 6061 is the most suitable for this application. Next, the theoretical mechanical behavior of the developed clamp concept is analyzed using two use cases. The final clamp concept is manufactured and compared in six mechanical tests with a state-of-the-art external fixator clamp, the Hoffmann 3, to evaluate the performance. Slippage and rotational tests are performed at three different tightening torques for all three diameters. The universal clamp performs significantly less on all six mechanical tests and as a consequence provides less stability to open fractures in comparison with the Hoffmann 3 clamp. Therefore, further development of the universal fixator is necessary to be successfully adopted as a Lifebox-idea to improve open and neglected fracture treatment in LMICs.