scholarly journals Differences between native and prosthetic knees in trochlear groove tracking based on a morphometric measurement of three-dimensional reconstruction models in Chinese people

2020 ◽  
Author(s):  
Shi Chang Chen ◽  
Hua Xu ◽  
Shaohua Gong
Keyword(s):  
Cross Section ◽  
Three Dimensional ◽  
Lateral Position ◽  
Trochlear Groove ◽  
Dimensional Reconstruction ◽  
Total Knee ◽  
Three Dimensional Models ◽  
Prosthetic Knees ◽  
Tissue Tension ◽  
Patellofemoral Kinematics

Abstract Background Prosthetic trochlear design is important to ideal postoperative patellofemoral kinematics and knee function. But there has been little research on the differences of trochlear groove trackings between the native and prosthetic knees. We aimed to investigate the differences between native and prosthetic knees through the entire trochlear length by three-dimensional computerized quantification.Methods Virtual total knee arthroplasty was performed, using three-dimensional models of 42 healthy knees that were matched to the femoral components of five different prosthesis systems. Coaxial planes were created along the trochlear groove in 3° increments, and the deepest points of the trochlear groove were marked in each plane. Taking the lower extremity mechanical axis as reference line, the differences in the mediolateral location of the groove tracking were analyzed between the native and prosthetic knees.Results From the proximal to the distal end, the native tracking started from 0° cross section and extended laterally and then medially with its turning point located in 69° cross section, while the prosthetic knees showed medial orientation throughout the trochlear length. Compared with the proximal portion of the native tracking, the prosthetic trackings extended along a paradoxical orientation and started from a more proximal and lateral position, with maximal discrepancy to, 3.2 mm in the 0° cross section. Distally, the prosthetic trackings were located significantly medial, with maximal discrepancy, to 2.4 mm in the 69° cross section.Conclusion The prosthetic trochlear design varies among different types, and does not conform to that of the native knee in terms of shape, orientation, and location, which may cause soft tissue tension imbalance and abnormal patellofemoral biomechanics during knee flexion. This study may be helpful for prosthetic trochlear design that accords with native anatomy so as to optimize patellofemoral biomechanics and decrease the risk of patellofemoral complications.

scholarly journals Differences in trochlear groove based on morphometric measurements of three-dimensional reconstruction models between native knees and five different femoral component designs in Chinese subjects

2020 ◽  
Author(s):  
shi chang chen ◽  
Hua Xu ◽  
Shaohua Gong
Keyword(s):  
Femoral Component ◽  
Cross Section ◽  
Cross Sections ◽  
Three Dimensional ◽  
Lateral Position ◽  
Trochlear Groove ◽  
Dimensional Reconstruction ◽  
Total Knee ◽  
Three Dimensional Models ◽  
Prosthetic Knees

Abstract Background: The p rosthetic trochlear design is important in postoperative patellofemoral kinematics and knee function. However, little research has been conducted on the differences in trochlear groove between native and prosthetic knees. We aimed to investigate the differences between Chinese native knees and prosthetic knees of five different femoral component designs using three-dimensional computerized quantification Of the entire trochlear length. Methods: Virtual total knee arthroplasty was performed using three-dimensional models of 42 healthy Chinese knees matched to the femoral components of five different prosthe tic systems by mechanical alignment . T he deepest points of the trochlear groove were marked in multiple cross sections for both the native and prosthetic knees . Taking the lower extremity mechanical axis as reference line, the differences in the mediolateral location of the trochlear groove were analyzed between the native and prosthetic knees. Results: From the proximal to the distal end, the native trochlear groove started from 0° cross section and extended laterally and then medially , with its turning point located at 69° cross section . T he prosthetic trochlear groove showed a similar medial orientation and extended more proximally, but varied in mediolateral location and the length extending to the intercondylar notch . Compared with the proximal portion of the native trochlear groove , the prosthetic knee s extended along a paradoxical orientation and started from a more proximal and lateral position to 3.2 mm in the 0° cross section , with maximal discrepancy. Distally, the prosthetic trochlear groove s were located significantly medial to 2.4 mm in the 69° cross section , with maximal discrepancy. Conclusion: The prosthetic trochlear design varie d among the different types and did not conform to the native knee in terms of shape, orientation, and location, which may cause soft tissue tension imbalance and abnormal patellofemoral biomechanics during knee flexion. This study may provide useful information for creating prosthetic trochlear design s that conform with the native knee anatomy to optimize patellofemoral biomechanics and reduce the risk of patellofemoral complications.

scholarly journals Differences in trochlear groove based on morphometric measurements of three-dimensional reconstruction models between native knees and five different femoral component designs in Chinese subjects

2020 ◽  
Author(s):  
Shi Chang Chen ◽  
Hua Xu ◽  
Shaohua Gong
Keyword(s):  
Femoral Component ◽  
Cross Section ◽  
Cross Sections ◽  
Three Dimensional ◽  
Lateral Position ◽  
Trochlear Groove ◽  
Dimensional Reconstruction ◽  
Total Knee ◽  
Three Dimensional Models ◽  
Prosthetic Knees

Abstract Background: The prosthetic trochlear design is important in postoperative patellofemoral kinematics and knee function. However, little research has been conducted on the differences in trochlear groove between native and prosthetic knees. We aimed to investigate the differences between Chinese native knees and prosthetic knees of five different femoral component designs using three-dimensional computerized quantification of the entire trochlear length.Methods: Virtual total knee arthroplasty was performed using three-dimensional models of 42 healthy Chinese knees matched to the femoral components of five different prosthetic systems by mechanical alignment. The deepest points of the trochlear groove were marked in multiple cross sections for both the native and prosthetic knees. Taking the lower extremity mechanical axis as reference line, the differences in the mediolateral location of the trochlear groove were analyzed between the native and prosthetic knees.Results: From the proximal to the distal end, the native trochlear groove started from 0° cross section and extended laterally and then medially, with its turning point located at 69° cross section. The prosthetic trochlear groove showed a similar medial orientation and extended more proximally, but varied in mediolateral location and the length extending to the intercondylar notch. Compared with the proximal portion of the native trochlear groove, the prosthetic knees extended along a paradoxical orientation and started from a more proximal and lateral position to 3.2 mm in the 0° cross section, with maximal discrepancy. Distally, the prosthetic trochlear grooves were located significantly medial to 2.4 mm in the 69° cross section, with maximal discrepancy.Conclusion: The prosthetic trochlear design varied among the different types and did not conform to the native knee in terms of shape, orientation, and location, which may cause soft tissue tension imbalance and abnormal patellofemoral biomechanics during knee flexion. This study may provide useful information for creating prosthetic trochlear designs that conform with the native knee anatomy to optimize patellofemoral biomechanics and reduce the risk of patellofemoral complications.

scholarly journals Evaluation of the Effect of the Sulcus Angle and Lateral to Medial Facet Ratio of the Patellar Groove on Patella Tracking in Aging Subjects with Stable Knee Joint

2018 ◽  
Vol 2018 ◽  
pp. 1-5
Author(s):  
Jianghui Qin ◽  
Dongyang Chen ◽  
Zhihong Xu ◽  
Dongquan Shi ◽  
Jin Dai ◽  
...  
Keyword(s):  
Lower Limb ◽  
Lateral Displacement ◽  
Three Dimensional ◽  
Trochlear Groove ◽  
Patellar Tilt ◽  
Sulcus Angle ◽  
Lateral Tilt ◽  
Computed Tomography Images ◽  
Three Dimensional Models ◽  
Patella Tracking

Purpose.To determine whether the sulcus angle and the lateral to medial facet ratio correlate with patella lateral displacement and tilt in patients without patella instability.Methods.Computed tomography images of the lower limb of 64 patients without known arthropathy were collected. Three-dimensional models of the lower limb with a unified coordinate system were rebuilt by using Mimics software. The sulcus angle, lateral to medial facet ratio, lateral trochlear inclination of the patellar groove, tibial tuberosity-trochlear groove (TT-TG) distance, bisect offset index, and lateral tilt of the patella were measured. Pearson’s correlation test was used to determine the relationship between the aforementioned parameters.Results.Data from 51 patients were analyzed. The sulcus angle was negatively correlated with lateral tilt inclination (p<0.001,r=0.8406) and positively correlated with the bisect offset index (p=0.003,r=0.634) and patellar tilt (p=0.03,r=0.551); the lateral to medial facet ratio was positively correlated with TT-TG distance (p=0.003,r=0.643) and bisect offset index (p=0.026,r=0.559).Conclusion.The sulcus angle and lateral to medial facet ratio of the patellar groove can influence patella tracking in patients with stable knee joints.

Research on Buckling Mechanism of U Type Steel Support’s Pinnas Based on ANSYS

2012 ◽  
Vol 466-467 ◽  
pp. 1271-1274
Author(s):  
Jian Zhuang Liu ◽  
Jia Li ◽  
Li Gan ◽  
Fang Fang Du
Keyword(s):  
Stress Distribution ◽  
Cross Section ◽  
Coal Mine ◽  
Optimization Design ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Type Steel ◽  
Buckling Failure ◽  
Simulation Results ◽  
Three Dimensional Models

The prevenient mechanical research on U type steel support focuses on two dimensional analysis in the installing plan. Interested in the buckling failure of U type steel support’s pinnas in one coal mine of Huainan Group, the authors build three dimensional models to stimulating 25U and 29U support. The appealing simulation results verify ANSYS’s 3-D computational capabilities about complicated section support. The main objective of their investigation has been to obtain some knowledge of the mechanism, stress distribution, and load magnitude in the support’s deforming. Further, the deviating longitudinal load play an accelerating deformation role on its distorting, which should be paied more attention to cross-section optimization, design of support parameters, and installing way of steel lacing.

Three-dimensional reconstruction of a mammalian Z-band from skeletal muscle

1992 ◽  
Vol 50 (1) ◽  
pp. 542-543
Author(s):  
J. P. Schroeter ◽  
M. A. Goldstein ◽  
J. P. Bretaudiere ◽  
R. L. Sass
Keyword(s):  
Skeletal Muscle ◽  
Cross Sections ◽  
Three Dimensional ◽  
Square Lattice ◽  
Back Projection ◽  
Axial Filament ◽  
Dimensional Reconstruction ◽  
Rat Soleus Muscle ◽  
Tilt Series ◽  
Three Dimensional Models

We have completed 3-d reconstructions of several regions of the Z-band in relaxed rat soleus muscle using the method of weighted back projection on a tilt series from two different longitudinal sections. Various displays of the reconstructions were interpreted after corrections for section shrinkage and comparisons to three dimensional models. Examination of cross-sections of the reconstructed Z-bands reveal that the lattice is in the small square form. We have previously shown that this form of the Z-band lattice is predominate in relaxed skeletal muscle. The reconstructions reveal that cross-connecting Z-filaments are arranged in opposing pairs along the axial filament. Successive pairs of filaments are rotated by ninety degrees about the axial filament, thus generating the four-fold appearance seen in the projected small square lattice.

A Model for Bending, Torsional, and Axial Vibrations of Micro- and Macro-Drills Including Actual Drill Geometry—Part I: Model Development and Numerical Solution

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Sinan Filiz ◽  
O. Burak Ozdoganlar
Keyword(s):  
Cross Section ◽  
Model Development ◽  
Three Dimensional ◽  
Circular Cross Section ◽  
Three Dimensional Model ◽  
Axial Thrust ◽  
One Dimensional ◽  
Three Dimensional Models ◽  
The Individual ◽  
Actual Geometry

Part I of this work presents a combined one-dimensional/three-dimensional approach for obtaining a unified model for the dynamics of micro- and macro-drills. To increase the numerical efficiency of the model, portions of the drill with circular cross-section (shank, extension, and tapered sections) are modeled using one-dimensional beam models without compromising model accuracy. A three-dimensional model is used for an accurate representation of the fluted section, considering the actual geometry with the pretwisted shape and axially varying (nonaxisymmetric) cross-section. The actual cross-section of the drills is incorporated to the model through a polynomial mapping while the pretwist effect is captured by defining a rotating reference frame. The boundary-value problem for both one- and three-dimensional models are derived using a variational approach, based on the extended Hamilton’s principle, and are subsequently solved by applying the spectral-Tchebychev technique. A component-mode synthesis is used for connecting the individual sections to obtain the dynamic model for the entire drill. Convergence of the model is studied by varying the number of polynomials for each section. The experimental validation of the model is included in Part II for both macro- and micro-drills. Also included in Part II is an analysis of drill dynamics for varying drill-geometry parameters and axial (thrust) force.

scholarly journals Morpho-Functional Analysis of Knee Implant Design for Total Knee Arthroplasty on the Example of the Trochlear Groove Orientation

10.29007/ch2k ◽  
2018 ◽  
Author(s):  
Malte Asseln ◽  
Mark Verjans ◽  
Darius Zanke ◽  
Klaus Radermacher
Keyword(s):  
Functional Analysis ◽  
Total Knee Arthroplasty ◽  
Rapid Prototyping ◽  
Knee Arthroplasty ◽  
External Rotation ◽  
Implant Design ◽  
Computer Assisted ◽  
Trochlear Groove ◽  
Total Knee ◽  
Patellofemoral Kinematics

Total knee arthroplasty (TKA) is widely accepted as a successful surgical intervention to treat osteoarthritis and other degenerative diseases of the knee. However, present statistics on limited survivorship and patient-satisfaction emphasize the need for an optimal endoprosthetic care. Although, the implant design is directly associated with the clinical outcome comprehensive knowledge on the complex relationship between implant design (morphology) and function is still lacking.The goal of this study was to experimentally analyze the relationship between the trochlear groove design of the femoral component (iTotal CR, ConforMIS, Inc., Bedford, MA, USA) and kinematics in an in vitro test setup based on rapid prototyping of polymer-based replica knee implants.The orientation of the trochlear groove was modified in five different variations in a self-developed computational framework. On the basis of the reference design, one was medially tilted (-2°) and four were laterally tilted (+2°, +4°, +6°, +8°). For manufacturing, we used rapid prototyping to produce synthetic replicates made of Acrylnitril-Butadien-Styrol (ABS) and subsequent post-processing with acetone vapor. The morpho-functional analysis of the replicates was performed in our experimental knee simulator. Tibiofemoral and patellofemoral kinematics were recorded with an optical tracking system during a semi-active flexion/extension (~10° to 90°) motion.Looking at the results, the patellofemoral kinematics, especially the medial/lateral translation and internal/external rotation were mainly affected. During low flexion, the patella had a more laterally position relative to the femur with increasing lateral trochlear orientation. The internal/external rotation initially differentiated and converged with flexion. Regarding the tibiofemoral kinematics, only the tibial internal/external rotation showed notable differences between the modified replica implants.We presented a workflow for an experimental morpho-functional analysis of the knee and demonstrated its feasibility on the example of the trochlear groove orientation which might be used in the future for comprehensive implant design parameter optimization, especially in terms of image based computer assisted patient-specific implants.

scholarly journals POINT CLOUD DATASET AND FEM FOR A COMPLEX GEOMETRY: THE SAN LUZI BELL TOWER CASE STUDY

2019 ◽  
Vol XLII-2/W11 ◽  
pp. 1047-1052
Author(s):  
I. Selvaggi ◽  
G. Bitelli ◽  
E. Serantoni ◽  
A. Wieser
Keyword(s):  
Laser Scanning ◽  
Structural Engineering ◽  
Structural Model ◽  
Complex Geometry ◽  
Three Dimensional ◽  
Potential Contribution ◽  
Bell Tower ◽  
Dimensional Reconstruction ◽  
Three Dimensional Models

<p><strong>Abstract.</strong> Detailed three-dimensional reconstruction of heritage objects is crucial for different purposes, such as analysis, preservation and maintenance, among others. Geomatics techniques allow acquiring complex and comprehensive information about geometry and current conditions of the surveyed objects in a short time, which is a great advantage for documentation and historical archives. The reconstruction of three-dimensional models is often performed using either image-based techniques, mainly Close Range Photogrammetry (CRP), including Structure from Motion approaches (SfM), or range-based techniques, such as Terrestrial Laser Scanning (TLS). These approaches have been widely applied in the field of Cultural Heritage to support multidisciplinary studies, from simple documentation to the monitoring of historical buildings, in restoration works or for structural analysis checks.</p><p>The present paper aims at exploring the potential contribution of Geomatics to Structural Engineering, by investigating capabilities and advantages of TLS for a vertical structure. The experiments presented herein were carried out in a notable case study, the San Luzi church, located in Zuoz (Switzerland) in the Upper Engadin. Its bell tower is about 60&amp;thinsp;m high and is equipped with four bells. Strong vibrations caused by the ringing of the bells have been observed in the past, and a structural model was desired to enable numerical evaluations of the response of the tower to various load situations by FEM.</p>

Investigation of Cell-Sensor Hybrid Structures by Focused Ion Beam (FIB) Technology

2006 ◽  
Vol 983 ◽  
Author(s):  
Andreas Heilmann ◽  
Frank Altmann ◽  
Andreas Cismak ◽  
Werner Baumann ◽  
Mirko Lehmann
Keyword(s):  
Cross Section ◽  
Mammalian Cells ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Three Dimensional ◽  
Nerve Cells ◽  
Cross Sectional ◽  
Dimensional Reconstruction ◽  
The Cross ◽  
Silicon Interface

AbstractFor the investigation of the adhesion of mammalian cells on a semiconductor biosensor structure, nerve cells on silicon neurochips were prepared for scanning electron microscopy investigations (SEM) and cross-sectional preparation by focused ion beam technology (FIB). The cross-sectional pattern demonstrates the focal adhesion points of the nerve cells on the chip. Finally, SEM micrographs were taken parallel to the FIB ablation to investigate the cross section of the cells slice by slice in order to demonstrate the spatial distribution of focal contact positions for a possible three-dimensional reconstruction of the cell-silicon interface.

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