Effect of Increasing Fracture Site Stiffness on Bone–Pin Interface Stress in the Equine Distal Limb Transfixation Cast: A Finite Element Analysis

2019 ◽  
Author(s):  
T.B. Lescun ◽  
S.B. Adams ◽  
R. Main ◽  
E. Nauman ◽  
G.J. Breur
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fracture Site ◽  
Interface Stress ◽  
Distal Limb ◽  
Element Analysis

The Effect of Increasing Fracture Site Stiffness on Bone–Pin Interface Stress and Foot Contact Pressure within the Equine Distal Limb Transfixation Cast: A Finite Element Analysis

2020 ◽  
Vol 33 (05) ◽  
pp. 348-355
Author(s):  
Timothy B. Lescun ◽  
Stephen B. Adams ◽  
Eric A. Nauman ◽  
Gert J. Breur
Keyword(s):  
Finite Element ◽  
Fracture Healing ◽  
Contact Pressure ◽  
Ex Vivo ◽  
Fracture Site ◽  
Interface Stress ◽  
Distal Limb ◽  
Element Analysis ◽  
Composite Tissue ◽  
Tissue Block

Abstract Objective The aim of this study was to determine how increasing stiffness of fracture site tissues distal to the pins in an equine distal limb transfixation cast influences stress at the bone–pin interface, within the bones distal to the transcortical pins, and contact pressure between the foot and the cast. Study Design A transfixation cast finite element model was used to compare the bone–pin interface stress, pin stress, bone stress distal to the pins and contact pressure between the foot and the cast, using six stiffness values for a composite tissue block representing progressive stages of fracture healing. Results Increasing stiffness of the composite tissue block resulted in a decrease in the maximum stresses at the bone–pin interface, an increase in stresses distal to the transcortical pins and a decrease in the maximum pin stresses. As the composite tissue block stiffness was increased, contact pressure between the bottom of the composite tissue block and the cast increased and the stress patterns surrounding the pin holes became less focal. Conclusion The findings of this study illustrate that with good foot to cast contact within a transfixation cast, increases in tissue stiffness due to progressive fracture healing are expected to reduce bone-pin interface stresses, and increase fracture site loading and stress. Increasing the contact pressure between the foot and the cast could reduce transfixation casting complications such as pin loosening, pin hole fracture and poor fracture healing, if these results transfer to ex vivo and in vivo settings.

Effect of Intramedullary Nailing Patterns On Interfragmentary Strain in a Mouse Femur Fracture: a Parametric Finite Element Analysis

2021 ◽  
Author(s):  
Gregory Lowen ◽  
Katherine Garrett ◽  
Moore-Lotridge Stephanie ◽  
Sasidhar Uppuganti ◽  
Scott A. Guelcher ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fracture Healing ◽  
Bone Repair ◽  
Bone Fractures ◽  
Fracture Site ◽  
Fracture Repair ◽  
Long Bone ◽  
Design Parameters ◽  
Element Analysis

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.

scholarly journals The Effect on the Fracture Healing following Femoral Neck Shortening after Osteoporotic Femoral Neck Fracture Treated with Internal Fixation: Finite Element Analysis

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Xiao Yu ◽  
Peng-ze Rong ◽  
Qing-jiang Pang ◽  
Xian-jun Chen ◽  
Lin Shi ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Concentration ◽  
Femoral Neck ◽  
Femoral Neck Fracture ◽  
Maximum Stress ◽  
Fracture Site ◽  
Cannulated Screws ◽  
Element Analysis ◽  
Neck Fracture

Objective. To evaluate the stress status of fracture site caused by femoral neck shortening and to analyze the stress of fracture site and the implants from the finite element point of view. Methods. CT scan data of hip of a normal adult female were collected. Three-dimensional reconstruction MICs and related module function simulation was used to establish the postoperative shortening model of femoral neck fracture with Pauwels   angle > 50 ° , which was treated with cannulated screws. The models were divided into four groups: normal femoral neck, shortening in 2.5 mm, shortening in 7.5 mm, and shortening in 12.5 mm. The finite element analysis software msc.nastran2012 was used, and the data of maximum stress and stress nephogram of fracture site and implants were carried out. Results. From normal femoral neck to shortening in 12.5 mm of the femoral neck, the maximum tensile stress increased gradually in the fracture site above the cannulated screws while compressive stress decreased gradually in the fracture site below the cannulated screws, and the maximum stress of the cannulated screws increased gradually with obvious stress concentration at the screw holes in the fracture site, and the peak value of stress concentration was about 179 MPa. Conclusion. The biomechanical environment of the fracture site changed by femoral neck shortening. With the increasing of femoral neck shortening, the stress of the fracture site and implants would be uneven; then, the stability of fracture site would become worse, and the possibility of implant sliding or even breakage would be increased.

Fixation of humeral intercondylar fractures using a lateral plate in 14 dogs supported by finite element analysis of repair

2007 ◽  
Vol 20 (04) ◽  
pp. 285-290 ◽  
Author(s):  
D. P. Comiskey ◽  
B. Mac Donald ◽  
C. B. Garvan ◽  
W. T. Mc Cartney
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Plate Fixation ◽  
Distal Humerus ◽  
Fracture Site ◽  
Fixation Method ◽  
Fe Modelling ◽  
Lateral Plate ◽  
Element Analysis ◽  
Micro Motion

SummaryFourteen Spaniels that presented with an intercondylar fracture of the distal humerus were managed using a lateral plate and an additional pin in twelve cases. Fixation of the fracture was achieved using a plate applied laterally which incorporated the transcondylar lag screw in the most distal hole. Of the 14 cases, two had poor results, one of which was a bilateral case, whilst the remaining 12 cases had good or very good results with only occasional stiffness or lameness. Finite element (FE) modelling of a distal humerus was generated, and loading of fracture repairs using a lateral plate and caudal plate was completed in a comparative study to determine which fixation method resisted micro-motion most effectively. Finite element analysis revealed that the lateral plate fixation provided significantly more resistance to micro movement at the fracture site that the caudal plate fixation, with 40% more micro-motion in the latter.

Finite Element Analysis of Positioning of Pin in Lapidus Procedure

2004 ◽  
Author(s):  
Haritha Royyuru ◽  
Yitung Chen ◽  
Hsuan-Tsung Hsieh ◽  
Anthony V. Borgia
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Site Effect ◽  
Fracture Site ◽  
Prototype Model ◽  
Fixation Device ◽  
Element Analysis ◽  
Modeling And Analysis ◽  
First Metatarsal ◽  
Device Simple

A finite element analysis was carried out to determine the optimum pin placement with the application of mini fixator in Lapidus procedure. Various parameters were considered for analysis like pin diameter, distance from fracture site, number of pins, distance of the rail from the fracture site, effect of width and length of the rail on gap closing, angle of fracture and pin angle. FEMLAB 2.3 is used for both modeling and analysis. A 2D model is constructed with the bone joint consisting of first metatarsal and cuneiform along with the fixation device. The dimensions of the model are taken similar to a prototype model of the foot and mini fixation device. Simple Static analysis is done as a beginning case which will be later developed to dynamic case.

Finite element analysis of a novel pin-sleeve system for external fixation of distal limb fractures in horses

2011 ◽  
Vol 190 (2) ◽  
pp. 260-267 ◽  
Author(s):  
Stefano Brianza ◽  
Vittoria Brighenti ◽  
Jennifer L. Lansdowne ◽  
Karsten Schwieger ◽  
Ludovic Bouré
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
External Fixation ◽  
Distal Limb ◽  
Element Analysis ◽  
Limb Fractures
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