Fracture stabilization with type II external fixator vs. type I external fixator with IM pin

2004 ◽  
Vol 17 (02) ◽  
pp. 91-96 ◽  
Author(s):  
Y. Shani ◽  
R. Shahar
Keyword(s):  
External Fixator ◽  
Three Dimensional ◽  
External Fixators ◽  
Type I ◽  
Equivalent Stiffness ◽  
Stiffness Modulus ◽  
Fracture Stabilization ◽  
Solid Models ◽  
Local Shear ◽  
Biomechanical Features

SummaryBilateral external fixator frames are frequently preferred over unilateral frames due to their superior rigidity. The objective of this study was to compare the biomechanical features of bilateral external fixators with those of unilateral external fixators that are combined with an intra-medullary pin. Three-dimensional, solid models were created of several unilateral and bilateral external fixator frames. The callus in the fracture gap was also modeled. Biomechanical analyses of all constructs were performed by the finite element method. This modeling approach allows the determination of stresses, displacements, and strains in the components of the various constructs, and thus the calculation of their relative stiffness. In addition, local shear strain values in the fracture gap, currently thought to be one of the deciding factors in the process of bone healing, can also be determined. The concept of equivalent stiffness modulus, which represents a weighed average stiffness of a construct to various loads, was defined. Using this concept, it was shown that when the intramedullary pin is well seated in the epiphyseal bone, the various unilateral frames have an equivalent stiffness modulus that is similar or even greater than that of bilateral frames with a similar arrangement of transcortical pins.

Three-Dimensional Modeling and Finite Element Analysis of an Ankle External Fixator

2020 ◽  
Vol 899 ◽  
pp. 94-102
Author(s):  
Nur Faiqa Ismail ◽  
Muhammmad Aiman Firdaus Bin Adnan ◽  
Solehuddin Shuib ◽  
Nik Ahmad Hambali Nik Abd Rashid
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
External Fixator ◽  
Three Dimensional ◽  
Von Mises Stress ◽  
External Fixators ◽  
Element Analysis ◽  
Stress And Deformation ◽  
The Stability ◽  
Von Mises

External fixator has played an important role in repairing fractured ankle bone. This surgery is done due to the several factors which are the bone is not normal position or has broken into several pieces. The external fixator will help the broken bone to grow and remodel back to the original appearance. However, there are some issues regarding to the stability of this fixation. Improper design and material are the major factor that decreased the stability since it is related to the deformation of the external fixator to hold the bone fracture area. This study aims to design a stable structure for constructing delta frame ankle external fixator to increase the stability of the fixation. There are two designs of external fixator with two types of material used in this present study. Both external fixators with different materials are analyzed in terms of von Mises stress and deformation by using a conventional Finite Element Analysis software; ANSYS Workbench V15. The result obtained shows the Model 1 with stainless steel has less stress and deformation distributions compared to the Model 2. Hence, by using Model 1 as the external fixator, the stability of the fixation can be increased.

Treatment of comminuted tibial shaft fractures in four dogs with the use of interlocking nail connected with type I external fixator

2012 ◽  
Vol 15 (4) ◽  
pp. 661-666
Author(s):  
A. Piórek ◽  
Z. Adamiak ◽  
M. Jaskólska ◽  
Y. Zhalniarovich
Keyword(s):  
External Fixator ◽  
Healing Process ◽  
Clinical Treatment ◽  
Bone Union ◽  
Type I ◽  
Tibial Shaft ◽  
Interlocking Nail ◽  
Fracture Stabilization ◽  
Shaft Fractures ◽  
Tibial Shaft Fractures

AbstractThe treatment of comminuted tibial shaft fractures in canine patients is burdened by significant risk which involves bone healing complications, such as delayed bone union. Complications may result from iatrogenic damage to blood vessels during fracture stabilization. To minimize this risk, treatment methods increasingly often rely on the concept of biological osteosynthesis. One of such methods involves the treatment of fractures with the use of new hybrid fixator consisted of an interlocking nail connected with type I external fixator. Connection of the nail with external fixator has been recently developed to maximize treatment efficiency. This manner of stabilization increases bone-fixator construct strength on forces acting in the place of fracture. It also enables fracture fixation with minimal damage of the blood supply of bone fragments. This article describes surgical procedure of stabilization of comminuted tibial bone fractures in four dogs by the use of interlocking nail connected with external fixator type I, discusses and evaluates the results of clinical treatment with the involvement of the said fixator. To control bone consolidation process the radiograms were taken in 6 and 8 week of healing.In all cases, the reviewed methods of clinical treatment were successful in producing bone union after eight week of healing. During the whole period of observations no complication was observed. In all cases the intramedullary nail were left in the medullary canal after the healing process was finished. The fixator supported quick restoration of limb function after treatment.

scholarly journals Development and Preliminary Trajectory Verification of the Electromotor-Driven Parallel External Fixator for Deformity Correction

2020 ◽  
Vol 10 (24) ◽  
pp. 9074
Author(s):  
Guotong Li ◽  
Jianfeng Li ◽  
Mingjie Dong ◽  
Shiping Zuo
Keyword(s):  
External Fixator ◽  
Inverse Kinematics ◽  
Medical Training ◽  
Three Dimensional ◽  
Deformity Correction ◽  
External Fixators ◽  
Artificial Bone ◽  
Adjustment Error ◽  
Adjustment Strategies ◽  
Searching Method

External fixators are widely used in deformity correction based on distraction osteogenesis. Traditionally, the rods are manually operated by patients several times a day, which will ensure the patient’s compliance, accumulative adjustment error, and trajectory deviation. To reduce the patients’ compliance and the complexity of adjustment, an electromotor-driven parallel external fixator is developed to gradually correct the deformity, which allows the fixator to be automatically adjusted and can correct any three-dimensional deformity with continuous stability. Two adjustment strategies are proposed through different trajectory control methods based on the inverse kinematics solution, and the trajectory and bone shape are generated to investigate the characteristics of the new bone more intuitively. The range of motion is performed utilizing the numerical searching method to assess the fixator’s correction capability. Finally, the trajectory verification experiment is carried out using the artificial bone model to perform the two adjustment strategies. The results show that the developed external fixator has high correction accuracy with 0.0172 mm, and can accurately and safely realize the preset correction trajectory. The developed fixator system can also be used as a teaching tool for medical training for clinicians to learn deformity correction technology.

scholarly journals Study on the relationship between the timing of conversion from external fixation to internal fixation and infection in the treatment of open fractures of extremities

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Zelin Ye ◽  
Shanwen Zhao ◽  
Canjun Zeng ◽  
Ziheng Luo ◽  
Song Yuan ◽  
...  
Keyword(s):  
Internal Fixation ◽  
External Fixation ◽  
External Fixator ◽  
Soft Tissues ◽  
Open Fractures ◽  
External Fixators ◽  
Type I ◽  
Infection Rates ◽  
Local Conditions ◽  
The Relationship

Abstract Objective To investigate the relationship between the infection rate and the timing of replacement of temporary external fixators with internal fixation, and the timing of immediate or delayed internal fixation after removal of temporary external fixation in the staging treatment modality of open fractures of extremities. Methods A retrospective analysis was performed on 122 cases of open fractures of extremities. External fixators were applied at the early stage and replaced with internal fixation when the condition of soft tissues improved and inflammatory indexes dropped to the normal range or showed a steady downward trend. Depending on the carrying time of external fixators after wound closure or healing, the patients were divided into three groups; the carrying time of groups A, B, and C was ≤ 14 days, 15–28 days, and > 28 days, respectively. Depending on the immediate or delayed internal fixation after removal of external fixator, patients were divided into group a (immediate internal fixation after removal of external fixator) and group b (delayed internal fixation after removal of external fixator, 5–7 days later). Results The infection rates of groups A, B, and C were 6.5%, 5.9%, and 23.3%, respectively. The differences among the three groups were statistically significant (P < 0.05). The infection rates of different Gustilo–Anderson fractures were as follows: no cases of infection out of 10 cases with type I fracture (0%); two cases of infection out of 35 cases with type II fracture (5.7%); three cases of infection out of 36 cases with IIIa fracture (8.3%); five cases of infection out of 28 cases with IIIB fracture (17.9%); and five cases of infection out of 13 cases with IIIC fracture (38.5%). The differences among the five groups were statistically significant. Conclusions The occurrence of infection of open fractures of extremities is associated with the fracture severity (Gustilo classification). For open fractures of Gustilo types I and II, the final internal fixation should be placed as soon as possible when the recovery of general and local conditions is good and the infection is controlled.

Clinical Value of Computer-Assisted Taylor Three-dimensional External Fixation in the Treatment of Tibiofibular Fracture (Preprint)

2020 ◽  
Author(s):  
Hongfeng Sheng ◽  
Weixing Xu ◽  
Bin Xu ◽  
Hongpu Song ◽  
Di Lu ◽  
...  
Keyword(s):  
Retrospective Study ◽  
Internal Fixation ◽  
External Fixation ◽  
External Fixator ◽  
Theoretical Basis ◽  
New Technology ◽  
Three Dimensional ◽  
Computer Assisted ◽  
Clinical Value

UNSTRUCTURED The retrospective study of Taylor's three-dimensional external fixator for the treatment of tibiofibular fractures provides a theoretical basis for the application of this technology. The paper collected 28 patients with tibiofibular fractures from the Department of Orthopaedics in our hospital from March 2015 to June 2018. After the treatment, the follow-up evaluation of Taylor's three-dimensional external fixator for the treatment of tibiofibular fractures and concurrency the incidence of the disease, as well as the efficacy and occurrence of the internal fixation of the treatment of tibial fractures in our hospital. The results showed that Taylor's three-dimensional external fixator was superior to orthopaedics in the treatment of tibiofibular fractures in terms of efficacy and complications. To this end, the thesis research can be concluded as follows: Taylor three-dimensional external fixation in the treatment of tibiofibular fractures is more effective, and the incidence of occurrence is low, is a new technology for the treatment of tibiofibular fractures, it is worthy of clinical promotion.

scholarly journals Application of a Proposed Multi-Positional Circumferential Arm Liposuction Method and Quantification of its Clinical Efficacy Evaluation

2021 ◽  
Author(s):  
Yunpeng Gu ◽  
Ning Kang ◽  
Qianwen Lv ◽  
Yue Qi ◽  
Zhenjun Liu ◽  
...  
Keyword(s):  
Clinical Efficacy ◽  
Quantitative Research ◽  
Three Dimensional ◽  
Reduction Rate ◽  
Full Description ◽  
Type I ◽  
Efficacy Evaluation ◽  
Level Of Evidence ◽  
Simple Measurement ◽  
Based Medicine

Abstract Background Upper arm liposuction mainly focuses on the posterolateral region, which may lead to a lack of harmony between the aspirated and unaspirated areas. In addition, the treatment effect of arm liposuction is often evaluated only by preoperative and postoperative photograph comparison and simple measurement; quantitative research on this topic is still lacking. Methods The multi-positional circumferential arm liposuction (MCAL) technique was proposed and applied to a total of 34 females in our hospital from 2017 to 2019. Three-dimensional data of 12 patients before the operation and after 2–3 months were collected and processed by 3D imaging, and the volume reduction rate was evaluated quantitatively. Results The MCAL method was successfully applied in the clinic, and its surgical effect was quantitatively studied. The mean follow-up time of 12 patients was (75.2 ±13.1) days, and the postoperative volume was significantly reduced. The postoperative volume of patients with type I, type II and type III decreased by (10.79 ±2.55)%, (17.25 ±3.02)% and (22.76 ±3.51)%, respectively. Conclusion Our new MCAL technique was successful, maximizing the esthetic results in upper limb contour refinements in the superficial fascial layer. The clinical efficacy of this proposed MCAL method was evaluated by CT and 3D digital technology, which provided further accuracy in demonstrating its effect on the shape of the arm. Level of evidence IV This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors https://www.springer.com.

A new model for packing of type-I collagen molecules in the native fibril

1981 ◽  
Vol 1 (10) ◽  
pp. 801-810 ◽  
Author(s):  
Karl A. Piez ◽  
Benes L. Trus
Keyword(s):  
Type I Collagen ◽  
Hexagonal Lattice ◽  
Three Dimensional ◽  
Equatorial Region ◽  
Type I ◽  
X Ray Diffraction ◽  
X Ray ◽  
Left Handed ◽  
Crystal Model ◽  
Collagen Molecules

A specific fibril model is presented consisting of bundles of five-stranded microfibrils, which are usually disordered (except axially) but under lateral compression become ordered. The features are as follows (where D = 234 residues or 67 nm): (1) D-staggered collagen molecules 4.5 D long in the helical microfibril have a left-handed supercoil with a pitch of 400–700 residues, but microfibrils need not have helical symmetry. (2) Straight-tilted 0.5-D overlap regions on a near-hexagonal lattice contribute the discrete x-ray diffraction reflections arising from lateral order, while the gap regions remain disordered. (3) The overlap regions are equivalent, but are crystallographically distinguished by systematic displacements from the near-hexagonal lattice. (4) The unit cell is the same as in a recently proposed three-dimensional crystal model, and calculated intensities in the equatorial region of the x-ray diffraction pattern agree with observed values.

A Finite Element Model of the Human Knee Joint for the Study of Tibio-Femoral Contact

2002 ◽  
Vol 124 (3) ◽  
pp. 273-280 ◽  
Author(s):  
Tammy L. Haut Donahue ◽  
M. L. Hull ◽  
Mark M. Rashid ◽  
Christopher R. Jacobs
Keyword(s):  
Finite Element ◽  
Articular Cartilage ◽  
Three Dimensional ◽  
Element Model ◽  
Maximum Pressure ◽  
Contact Behavior ◽  
Element Size ◽  
Solid Models ◽  
Flexion Extension ◽  
Three Dimensional Coordinate

As a step towards developing a finite element model of the knee that can be used to study how the variables associated with a meniscal replacement affect tibio-femoral contact, the goals of this study were 1) to develop a geometrically accurate three-dimensional solid model of the knee joint with special attention given to the menisci and articular cartilage, 2) to determine to what extent bony deformations affect contact behavior, and 3) to determine whether constraining rotations other than flexion/extension affects the contact behavior of the joint during compressive loading. The model included both the cortical and trabecular bone of the femur and tibia, articular cartilage of the femoral condyles and tibial plateau, both the medial and lateral menisci with their horn attachments, the transverse ligament, the anterior cruciate ligament, and the medial collateral ligament. The solid models for the menisci and articular cartilage were created from surface scans provided by a noncontacting, laser-based, three-dimensional coordinate digitizing system with an root mean squared error (RMSE) of less than 8 microns. Solid models of both the tibia and femur were created from CT images, except for the most proximal surface of the tibia and most distal surface of the femur which were created with the three-dimensional coordinate digitizing system. The constitutive relation of the menisci treated the tissue as transversely isotropic and linearly elastic. Under the application of an 800 N compressive load at 0 degrees of flexion, six contact variables in each compartment (i.e., medial and lateral) were computed including maximum pressure, mean pressure, contact area, total contact force, and coordinates of the center of pressure. Convergence of the finite element solution was studied using three mesh sizes ranging from an average element size of 5 mm by 5 mm to 1 mm by 1 mm. The solution was considered converged for an average element size of 2 mm by 2 mm. Using this mesh size, finite element solutions for rigid versus deformable bones indicated that none of the contact variables changed by more than 2% when the femur and tibia were treated as rigid. However, differences in contact variables as large as 19% occurred when rotations other than flexion/extension were constrained. The largest difference was in the maximum pressure. Among the principal conclusions of the study are that accurate finite element solutions of tibio-femoral contact behavior can be obtained by treating the bones as rigid. However, unrealistic constraints on rotations other than flexion/extension can result in relatively large errors in contact variables.

scholarly journals Protease-dependent versus -independent cancer cell invasion programs: three-dimensional amoeboid movement revisited

2009 ◽  
Vol 185 (1) ◽  
pp. 11-19 ◽  
Author(s):  
Farideh Sabeh ◽  
Ryoko Shimizu-Hirota ◽  
Stephen J. Weiss
Keyword(s):  
Cancer Cells ◽  
Type I Collagen ◽  
Three Dimensional ◽  
Amoeboid Movement ◽  
Type I ◽  
Collagen Network ◽  
Normal Tissues ◽  
Tissue Invasion ◽  
Absolute Requirement ◽  
Cross Links

Tissue invasion during metastasis requires cancer cells to negotiate a stromal environment dominated by cross-linked networks of type I collagen. Although cancer cells are known to use proteinases to sever collagen networks and thus ease their passage through these barriers, migration across extracellular matrices has also been reported to occur by protease-independent mechanisms, whereby cells squeeze through collagen-lined pores by adopting an ameboid phenotype. We investigate these alternate models of motility here and demonstrate that cancer cells have an absolute requirement for the membrane-anchored metalloproteinase MT1-MMP for invasion, and that protease-independent mechanisms of cell migration are only plausible when the collagen network is devoid of the covalent cross-links that characterize normal tissues.

scholarly journals Accumulation of motile elongated micro-organisms in turbulence

2013 ◽  
Vol 739 ◽  
pp. 22-36 ◽  
Author(s):  
Caijuan Zhan ◽  
Gaetano Sardina ◽  
Enkeleida Lushi ◽  
Luca Brandt
Keyword(s):  
Turbulent Flow ◽  
Three Dimensional ◽  
Laminar Flows ◽  
Marine Life ◽  
Prolate Spheroids ◽  
Linear Shear ◽  
Local Shear ◽  
Micro Organisms ◽  
Hydrodynamic Effects ◽  
Preferential Alignment

AbstractWe study the effect of turbulence on marine life by performing numerical simulations of motile micro-organisms, modelled as prolate spheroids, in isotropic homogeneous turbulence. We show that the clustering and patchiness observed in laminar flows, linear shear and vortex flows, are significantly reduced in a three-dimensional turbulent flow mainly because of the complex topology; elongated micro-organisms show some level of clustering in the case of swimmers without any preferential alignment whereas spherical swimmers remain uniformly distributed. Micro-organisms with one preferential swimming direction (e.g. gyrotaxis) still show significant clustering if spherical in shape, whereas prolate swimmers remain more uniformly distributed. Due to their large sensitivity to the local shear, these elongated swimmers react more slowly to the action of vorticity and gravity and therefore do not have time to accumulate in a turbulent flow. These results show how purely hydrodynamic effects can alter the ecology of micro-organisms that can vary their shape and their preferential orientation.

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