Mathematical Modelling of Destabilization Stress Factors of Stable-Elastic Fixation of Distal Trans- and Suprasyndesmotic Fibular Fractures

Abstract

Introduction. Specification of possible stress factors destabilizing the fibula stable osteosynthesis by the intramedullary nail with distal blocking and elastic fixation of distal syndesmosis by the thread with endobuttons by mathematical modelling of distal unstable ankle injuries. Material and Methods. We studied the thread tension during the combined stable-elastic fixation of unstable injuries of the ankle joint in cross-syndesmosis fractures of the fibula (B, C Danis–Weber classification), which includes a one-time stable minimally invasive fixation with the intramedullary nail and elastic fixation by the thread with endobuttons. We used a titanium alloy for the intramedullary nail and polyester for the thread. The deformed state was studied using the methods of mechanics. Results. A model of a fractured fibula blocked with the intramedullary nail and fixed with the elastic thread was developed. A formulation to specify the rational tension forces of the elastic thread depending on the parameters of the fibula and intramedullary blocking nail and on the location of the bone injury was obtained. The effect of foot rotation on the thread tension was investigated. The results of theoretical research should be implemented in medical practice. Conclusions. A mathematical model of the damaged fibula blocked by the intramedullary nail and fixed with the elastic thread was developed. Dependences for calculation of tension of the fixing thread were obtained. A slight increase in thread tension during foot rotation was found.

Determining the Tightrope Tightening Force for Effective Fixation of the Tibiofibular Syndesmosis during Osteomeatal Synthesis of Fibula Injuries

“…] is satisfied, will correspond to the permissible value of the tightrope tightening force [P] = P. The permissible deflection value is selected from the condition of preserving the geometrically correct shape of the bone after rupture consolidation (healing) [69][70][71]. If the permissible deflection value is exceeded, a crack or the edges of a broken bone may open, as well as damage to the crack edges when they come into contact, displacement of bone fragments, etc.…”

“…By gradually increasing the value of the tightrope tightening force, we control that the maximum bone deflection does not exceed the permissible value [w]. The value of the tightrope tightening force P, under which the condition w(x) = wmax = [w] is satisfied, will correspond to the permissible value of the tightrope tightening force [P] = P. The permissible deflection value is selected from the condition of preserving the geometrically correct shape of the bone after rupture consolidation (healing) [69][70][71]. If the permissible deflection value is exceeded, a crack or the edges of a broken bone may open, as well as damage to the crack edges when they come into contact, displacement of bone fragments, etc.…”

Analytical Model of Structural Damping in Friction Module of Shell Shock Absorber Connected to Spring

“…Te problems of contact mechanics are of great interest to researchers as a result of their practical application in the feld of mechanical engineering [43,44], the construction industry [45,46], biomechanics, etc. [47,48]. In general, when solving contact problems, researchers pay considerable attention to the analysis of the strength, rigidity, and stability of the contacting elements [49,50].…”

Analytical Modeling of the Interaction of a Four Implant-Supported Overdenture with Bone Tissue

“…A number of modern studies are devoted to contact problems for shell rod systems, taking into account the energy dissipation during mutual slippage in contact pairs [ 25 , 26 , 27 ]. Analytical [ 28 , 29 , 30 ], analytic-numerical [ 31 , 32 , 33 ], and experimental [ 34 , 35 ] approaches to the study of stresses in composite, substantially inhomogeneous structures also deserve attention.…”