_Applied_  
_sciences_  
_Article_  
Engineering and Manufacturing of a Dynamizable Fracture Fixation Device System  
**[PERSON] 1,2\({}^{\copyright}\)**, [PERSON] 3,*\({}^{\copyright}\)**, [PERSON] 1,2\({}^{\copyright}\)**, [PERSON] 1,2\({}^{\copyright}\)**,  
**[PERSON] 4\({}^{\copyright}\)**, [PERSON] 5 and [PERSON] 1,2  
1 Department of Mechanical and Aerospace Engineering (DIMEAS), Politecnico di Torino, 10129 Turin, Italy; [PERSON](G.D.); [EMAIL_ADDRESS] (M.T.); [PERSON] (G.P.); [EMAIL_ADDRESS] (A.L.A.)  
2 Polito\({}^{\copyright}\)Med Lab, Politecnico di Torino, 10129 Turin, Italy  
3 Department of Electrical, Electronics and Computer Engineering (DIEEI), University of Catania, 95124 Catania, Italy  
4 Department of Engineering, University of Perugia, 06125 Perugia, Italy; [EMAIL_ADDRESS]  
5 Intrauma S.p.A., 10098 Rivoli, Italy; [EMAIL_ADDRESS]  
* Correspondence: [EMAIL_ADDRESS]  
Received: 9 July 2020; Accepted: 24 September 2020; Published: 29 September 2020  
**Featured Application: The article illustrates the workflow towards a new dynamizable plate design, prototyping and certification; performance data concerning this plate have been reported and can be used as a reference.**  
**Abstract: The present work illustrates the dynamization of an orthopaedic plate for internal fracture fixation which is thought to shorten healing times and enhance the quality of the new formed bone. The dynamization is performed wirelessly thanks to a magnetic coupling. The paper shows the peculiarities of the design and manufacturing of this system: it involves two components, sliding with respect to each other with an uncertain coefficient of friction, and with a specific compounded geometry; there are stringent limits on component size, and on the required activation energy. Finally, the device belongs to medical devices and, as such, it must comply with the respective regulation (EU 2017/745, ASTM F382). The design of the dynamizable fracture fixation plate has required verifying the dynamic of the unlocking mechanism through the development of a parametric multibody model which has allowed us to fix the main design variables. As a second step, the fatigue strength of the device and the static strength of the whole bone-plate system was evaluated by finite element analysis. Both analyses have contributed to defining the final optimized geometry and the constitutive materials of the plate; finally, the respective working process was set up and its performance was tested experimentally on a reference fractured femur. As a result of these tests, the flexural stiffness of the bone-plate system resulted equal to 370 N/mm, while a maximum bending moment equal to 75.3 kN\(\cdot\)mm can be withstood without plate failure. On the whole, the performance of this dynamic plate was proved to be equal or superior to those measured for static plates already on the market, with excellent clinical results. At the same time, pre-clinical tests will be an interesting step of the future research, for which more prototypes are now being produced.**  
**Keywords: fracture synthesis; internal fixation; stress analysis; dynamizable plate; mechanical tests; medical device manufacturing**