scholarly journals The effect of head trauma on fracture healing: biomechanical testing and finite element analysis

2010 ◽  
Vol 44 (4) ◽  
pp. 313-321 ◽  
Author(s):  
Firat Ozan
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Graeme R. Paul ◽  
Esther Wehrle ◽  
Duncan C. Tourolle ◽  
Gisela A. Kuhn ◽  
Ralph Müller

AbstractMechanical loading allows both investigation into the mechano-regulation of fracture healing as well as interventions to improve fracture-healing outcomes such as delayed healing or non-unions. However, loading is seldom individualised or even targeted to an effective mechanical stimulus level within the bone tissue. In this study, we use micro-finite element analysis to demonstrate the result of using a constant loading assumption for all mouse femurs in a given group. We then contrast this with the application of an adaptive loading approach, denoted real time Finite Element adaptation, in which micro-computed tomography images provide the basis for micro-FE based simulations and the resulting strains are manipulated and targeted to a reference distribution. Using this approach, we demonstrate that individualised femoral loading leads to a better-specified strain distribution and lower variance in tissue mechanical stimulus across all mice, both longitudinally and cross-sectionally, while making sure that no overloading is occurring leading to refracture of the femur bones.


Author(s):  
Graeme R. Paul ◽  
Esther Wehrle ◽  
Duncan C. Tourolle ◽  
Gisela A. Kuhn ◽  
Ralph Müller

AbstractMechanical loading allows both investigation into the mechano-regulation of fracture healing as well as interventions to improve fracture-healing outcomes such as delayed healing or non-unions. However, loading is seldom individualised or even targeted to an effective mechanical stimulus level within the bone tissue. In this study, we use micro-finite element analysis to demonstrate the result of using a constant loading assumption for all mouse femurs in a given group. We then contrast this with the application of an adaptive loading approach, denoted real time Finite Element (rtFE) adaptation, in which micro-computed tomography images provide the basis for micro-FE based simulations and the resulting strains are manipulated and targeted to a reference distribution. Using this approach, we demonstrate that individualised femoral loading leads to a better-specified strain distribution and lower variance in tissue mechanical stimulus across all mice, both longitudinally and cross-sectionally, while making sure that no overloading is occurring leading to refracture of the femur bones.


Author(s):  
Gregory Lowen ◽  
Katherine Garrett ◽  
Moore-Lotridge Stephanie ◽  
Sasidhar Uppuganti ◽  
Scott A. Guelcher ◽  
...  

Abstract Delayed long bone fracture healing and nonunion continue to be a significant socioeconomic burden. While mechanical stimulation is known to be an important determinant of the bone repair process, understanding how the magnitude, mode, and commencement of interfragmentary strain (IFS) affect fracture healing can guide new therapeutic strategies to prevent delayed healing or non-union. Mouse models provide a means to investigate the molecular and cellular aspects of fracture repair, yet there is only one commercially available, clinically-relevant, locking intramedullary nail (IMN) currently available for studying long bone fractures in rodents. Having access to alternative IMNs would allow a variety of mechanical environments at the fracture site to be evaluated, and the purpose of this proof-of-concept finite element analysis study is to identify which IMN design parameters have the largest impact on IFS in a murine transverse femoral osteotomy model. Using the dimensions of the clinically relevant IMN as a guide, the nail material, distance between interlocking screws, and clearance between the nail and endosteal surface were varied between simulations. Of these parameters, changing the nail material from stainless steel (SS) to polyetheretherketone (PEEK) had the largest impact on IFS. Reducing the distance between the proximal and distal interlocking screws substantially affected IFS only when nail modulus was low. Therefore, IMNs with low modulus (e.g., PEEK) can be used alongside commercially available SS nails to investigate the effect of initial IFS or stability on fracture healing with respect to different biological conditions of repair in rodents.


Author(s):  
István Kádas ◽  
Tamás Tököly ◽  
Tamás Bíró ◽  
Zsuzsa Bíró ◽  
Dániel Kádas

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