Finite Element Method Oriented Failure Analysis of Medical Implants: Artificial Knee

2013 ◽  
Author(s):  
Sudesh Sivarasu ◽  
Sam Prasanna James ◽  
T. Lazar Mathew
Keyword(s):  
Finite Element ◽  
Slight Modification ◽  
Orthopedic Implants ◽  
Maximum Load ◽  
The Body ◽  
Rotating Platform ◽  
Linear Deformation ◽  
Component Design ◽  
Flexion Extension ◽  
Total Knee

The application of Finite Element Modelling in Medical Applications has been evolving as the field of high importance especially in the development of medical devices. The Total Knee Arthroplasty [TKA] has been in existence for over 6 decades till now. The generic artificial knee implants used in the TKA have the restriction in its range of motion with around 90 degrees. A new design allowing flexion extension range of over 120 degrees was designed with a view to facilitate partial squatting and the same is used for the analysis purpose. The new design of the artificial knee has a flexion extension range of 130 degrees. The higher flexion of the knee is obtained by use of the rotating platform knee design principle and also by adopting a multi-radii approach for the femoral component design. The loading conditions of 10 times the body weight are considered for structural analyses of the novel knee. A maximum load of 700Kg were subjected on the knee implants. The finite element analyses of the designs were carried out based on standard biomaterial used in orthopedic implants. In this paper we have discussed the results of analyses of an artificial knee with Ti alloy. The results of the analyses were used in identifying areas of extreme stresses within the design and the spot prone for higher deformation. Based on these results slight modification on the designs was carried out. The results are also verified whether the body is within the linear deformation levels. As the results obtained were very satisfactory the models have been recommended for prototyping.

STRUCTURAL RESPONSES OF A NOVEL HIGH FLEXION KNEE (SS316–UHMWPE) USED IN TOTAL KNEE ARTHROPLASTY USING FINITE ELEMENT ANALYSIS

2009 ◽  
Vol 04 (03) ◽  
pp. 289-298 ◽  
Author(s):  
SUDESH SIVARASU ◽  
LAZAR MATHEW
Keyword(s):  
Finite Element ◽  
Total Knee Arthroplasty ◽  
Knee Arthroplasty ◽  
Maximum Yield ◽  
Slight Modification ◽  
The Body ◽  
Element Analysis ◽  
Linear Deformation ◽  
Flexion Extension ◽  
Total Knee

The application of finite element modeling in medical applications has been evolving as the field of high importance especially in the development of medical. The generic artificial knee implants used in the total knee arthroplasty have the restriction in its range of motion with around 90 degrees. A new design allowing flexion extension range of over 120 degrees has been designed with a view to facilitate partial squatting and the same is used for the analysis purpose. The loading conditions of 10 times the body weight are considered. Finite element analyses of this design have been carried out based on standard biomaterial used in orthopaedic implants. In this paper we discuss the results of analyses of an artificial knee with stainless steel alloy. The results of the analyses were used in identifying areas of extreme stresses within the design and the spot prone for higher deformation. Based on these results slight modification on the designs was carried out. The results are also verified whether the body is within the linear deformation levels. As the results obtained were very satisfactory the models have been recommended for prototyping. It is verified from the results that the new models respond positive till a load of 300 kg and then they enter into the maximum yield stress levels. However, in reality, the loading on an artificial knee is less than 300 kg. So the results are inferred positive and the models were sent for prototyping.

scholarly journals Finite-Element-Based Design Optimisation of a Novel High Flexion Knee Used in Total Knee Arthroplasty

2008 ◽  
Vol 5 (2) ◽  
pp. 77-87 ◽  
Author(s):  
Sudesh Sivarasu ◽  
Lazar Mathew
Keyword(s):  
Finite Element ◽  
Total Knee Arthroplasty ◽  
Knee Arthroplasty ◽  
Slight Modification ◽  
The Body ◽  
Finite Element Analyses ◽  
Linear Deformation ◽  
Extreme Stress ◽  
Flexion Extension ◽  
Total Knee

The application of finite-element modelling in medical applications has been evolving as a field of high importance in recent times. Total knee arthroplasty (TKA) has been in existence for over 6 decades. The generic artificial knee implants used in the TKA have a restricted range of motion of around 90 degrees. A new design allowing a flexion extension range of over 120 degrees was designed and is used for analysis. Loading conditions of 10 times the body weight are considered. The finite-element analyses of the designs were carried out based on standard biomaterials used in orthopaedic implants. The results of the analyses were used in identifying areas of extreme stress within the design and the spots prone to higher deformation. On the basis of these results slight modification of the designs was carried out. The results are also verified whether the body is within the linear deformation levels. The results obtained were very satisfactory and based on these results the models have been recommended for prototyping.

KINEMATIC ANALYSIS AND 3D FINITE ELEMENT ANALYSIS OF A MOBILE-BEARING ARTIFICIAL HIGH FLEXION KNEE

2009 ◽  
Vol 21 (04) ◽  
pp. 279-285 ◽  
Author(s):  
Sudesh Sivarasu ◽  
Lazar Mathew
Keyword(s):  
Finite Element ◽  
Knee Replacement ◽  
Orthopedic Implants ◽  
The Body ◽  
Implant Design ◽  
Activity Levels ◽  
Element Analysis ◽  
High Flexion ◽  
Flexion Extension ◽  
Total Knee

Total knee arthroplasty (TKA) has been the end-time surgical procedure for pain relief and movement restoration in cases of severe arthritis. The knee implant design plays a vital role in deciding the activity levels of a patient after total knee replacement (TKR). In about 90% of younger patients undergoing the knee replacement surgeries, the restriction is not from the subject but from the implant design. This paper discusses parameters affecting the activity levels after TKR. It also briefs the design aspects of a novel knee design that allows the normal high flexion activity even after TKR. The application of finite element modeling in medical applications has been evolving as the field of high importance especially in the development of medical devices. The TKA has been in existence for over six decades till now. The generic artificial knee implants used in the TKA have the restriction in its range of motion of about 90°. A new design allowing flexion extension range of over 120° was designed with a view to facilitate partial squatting and the same is used for the analysis purpose. The loading conditions of 10 times the body weight are considered. The finite element analyses of the designs were carried out based on standard biomaterial used in orthopedic implants. In this paper, we have discussed the results of analyses of an artificial knee with titanium (Ti) alloy. The results of the analyses were used in identifying areas of extreme stresses within the design and the spot prone for higher deformation. Based on these results, slight modification on the designs was carried out. The results are also verified whether the body is within the linear deformation levels. As the results obtained were very satisfactory, the models have been recommended for prototyping.

Development of a New Artificial Knee Joint for an Asian and Middle Eastern Population

2013 ◽  
Author(s):  
Harcharan Singh Ranu
Keyword(s):  
Finite Element ◽  
Body Weight ◽  
Maximum Load ◽  
The Body ◽  
The Other ◽  
Elastic Behavior ◽  
Loading Conditions ◽  
Load Bearing Capacity ◽  
Linear Elastic ◽  
Materials Used

Design of an artificial knee was developed using computer 3-D modeling, the high flexion knee was obtained by using a multi-radii design pattern, The increase of final 20 degrees in flexion was obtained by increasing the condylar radii of curvature. The model of the high flexion knee was developed and one of the models was subjected to finite element modeling and analysis. The compositions of components in the artificial knee were, femoral component and the tibial component were metal, whereas the patellar component and the meniscal insert were made using polyethylene. The metal component used for the analysis in this study was Ti6Al4V and the polyethylene used was UHMWPE. Overall biomaterials chosen were: meniscus (UHMWPE, mass = 0.0183701 kg, volume = 1.97518e-005 m3), tibial component (Ti6Al4V, mass = 0.0584655 kg, volume = 1.32013e-005 m3), femoral component (Ti6Al4V, mass = 0.153122 kg, volume = 3.45742e-005 m3), total artificial assembly (mass = 0.229958 kg, volume = 6.75e-005m3). However, in this design the load had been taken to 10 times the body weight. The weight over single knee is only half the maximum load as the load is shared between the two knee joints. Following were the loading conditions, taking average body weight to be 70Kgs and taking extreme loading conditions of up to 10 times the body weight, i.e. 700Kgs on each of the leg performed the Finite Element Analysis (FEA) over the newly designed knee. The loading was done at an increment of 100 Kgs. The loading conditions and the meshing details for the analysis of the assembly were Jacobian check: 4 points, element size: 0.40735 cm, tolerance: 0.20367 cm, quality: high, number of elements: 80909, number of nodes: 126898. A maximum load of 600 Kgs is optimum for this model. The other components observed linear elastic behavior for the applied loads. Based on these results it was determined that the load bearing capacity of the model were well within the failure levels of the materials used for the analysis. A maximum load of 600 Kgs is optimum for this model. The other components observed linear elastic behavior for the applied loads. Based on these results it was determined that the load bearing capacity of the model were well within the failure levels of the materials used for the analysis. Conclusion drawn from this is that for the first time an innovative new design of an artificial knee joint to suite a segment of some religious population has been developed. This allows them to pray, bend in different positions and squat without too much difficulty.

A Finite Element Model of a Rotating Platform Total Knee Employing a Nonlinear, Dual-Surface-Contact Formulation

2000 ◽  
Author(s):  
Jason K. Otto ◽  
Thomas D. Brown ◽  
John J. Callaghan
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Mobile Bearing ◽  
Element Model ◽  
Polyethylene Insert ◽  
Rotating Platform ◽  
Mobile Interface ◽  
Surface Contact ◽  
Total Knee

Abstract Mobile bearing total knees avoid the conformity/constraint tradeoff of fixed bearing total knees. However, a recent in vivo fluoroscopic study of the most popular mobile bearing total knee in the U.S. showed that bearing motion failed to occur in half of the patients observed. A nonlinear, multiple-surface contact finite element model of a rotating platform total knee was therefore developed to investigate the interaction at the “mobile” interface (contact between the tibial tray and the polyethylene insert) under physiologically relevant loads (1–4 BW) and rotations (10° endorotation). The data showed that there was a linear relationship between axial load and the torque resisting endorotation. Peak contact stresses were located on the medial and lateral peripheral edges of the polyethylene insert. All relative rotation occurred at the “mobile” interface. The same trends were seen in a complementary experimental study of the same components, suggesting that the finite element model is valid under these loading conditions.

Gait Cycle Finite Element Comparison of Rotating-Platform Total Knee Designs

2003 ◽  
Vol 410 ◽  
pp. 181-188 ◽  
Author(s):  
Jason K. Otto ◽  
John J. Callaghan ◽  
Thomas D. Brown
Keyword(s):  
Finite Element ◽  
Gait Cycle ◽  
Rotating Platform ◽  
Total Knee

Comparison of Knee Kinematics and Kinetics during Stair Descent in Single- and Multi-Radius Total Knee Arthroplasty

2019 ◽  
Vol 33 (10) ◽  
pp. 1020-1028 ◽  
Author(s):  
Bonnie Sumner ◽  
John McCamley ◽  
David J. Jacofsky ◽  
Marc C. Jacofsky
Keyword(s):  
Total Knee Arthroplasty ◽  
Knee Arthroplasty ◽  
Knee Kinematics ◽  
The Body ◽  
Stair Descent ◽  
Flexion Extension ◽  
Postoperative Time ◽  
Total Knee ◽  
Infrared Cameras ◽  
Kinematics And Kinetics

AbstractDespite continuing advances, nearly 20% of patients remain dissatisfied with their total knee arthroplasty (TKA) outcomes. Single-radius (SR) and multiradius (MR) TKA designs are two commonly used knee replacement designs based on competing theories of the flexion/extension axis of the knee. Our aim was to characterize stair descent kinematics and kinetics in SR and MR TKA subjects. We hypothesized that 1 year after TKA, patients who received SR TKA will more closely replicate the knee kinematics and kinetics of healthy age-matched controls during stair descent, than will MR TKA patients. SR subjects (n = 12), MR subjects (n = 12), and age-matched controls (n = 12) descended four stairs affixed to force platforms, while 10 infrared cameras tracked markers attached to the body to collect kinematic and kinetic data. Both patient groups had improvements in stair descent kinetics and kinematics at the 1-year postoperative time point. However, SR TKA subjects were indistinguishable statistically from age-matched controls, while MR TKA subjects retained many differences from controls. Similar to previous reports for level walking, the SR knee design performs closer to healthy controls than MR knees during stair descent. This study demonstrates that patients who receive SR TKA have more improved kinematic normalization during stair descent postoperatively than those who received an MR TKA.

scholarly journals Pre-Planned and Non-Planned Agility in Patients Ongoing Rehabilitation after Knee Surgery: Design, Reliability and Validity of the Newly Developed Testing Protocols

Diagnostics ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 146
Author(s):  
Ivan Peric ◽  
Miodrag Spasic ◽  
Dario Novak ◽  
Sergej Ostojic ◽  
Damir Sekulic
Keyword(s):  
Total Knee Arthroplasty ◽  
Body Mass ◽  
Knee Arthroplasty ◽  
Arthroscopic Surgery ◽  
The Body ◽  
Clinical Population ◽  
Pearson's R ◽  
Total Knee ◽  
Type Of Surgery ◽  
Pearson’S R

Background: Due to its association with the risk of falling and consequent injury, the importance of agility is widely recognized, but no study so far has examined the different facets of agility in an untrained/clinical population. The aim of this study was to evaluate the reliability, validity, and correlates of newly developed tests of non-planned agility (NPA) and pre-planned agility (PPA) in an untrained/clinical sample. Methods: The sample comprised 38 participants older than 40 years (22 females, age: 56.1 ± 17.3 years, height: 170.4 ± 10.8 cm, mass: 82.54 ± 14.79 kg) who were involved in a rehabilitation program following total knee arthroplasty and knee arthroscopy. Variables included age, gender, type of surgery, history of fall, anthropometrics/body composition, and newly developed tests of NPA and PPA. Results: The results showed the high inter-testing- (ICC > 0.95, CV < 9%), and intra-testing-reliability (ICC > 0.96, CV < 9) of the newly developed tests. PPA and NPA were found to be valid in differentiation between age groups (>50 yrs. vs. <50 yrs.), and genders, with better performance in younger participants and males. Only NPA differentiated participants according to type of surgery, with better performance in those who had arthroscopic surgery, than those who had total knee arthroplasty. No differences in NPA and PPA were established between groups based on fall-history. In females, the body mass (Pearson’s r = 0.58 and 0.59, p < 0.001) and body fatness (Pearson’s r = 0.64 and 0.66, p < 0.001) were negatively correlated, while the lean body mass (Pearson’s r = 0.70 and 0.68, p < 0.001) was positively correlated with PPA and NPA. The NPA and PPA were highly correlated (Pearson’s r = 0.98, p < 0.001). Conclusions: We found that the proposed tests are reliable when evaluating agility characteristics in an untrained/clinical population after knee arthroplasty/arthroscopy. Further evaluation of the specific validity of the proposed tests in other specific subsamples is warranted.

scholarly journals The biomechanical effect on the adjacent L4/L5 segment of S1 superior facet arthroplasty: a finite element analysis for the male spine

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Zewen Shi ◽  
Lin Shi ◽  
Xianjun Chen ◽  
Jiangtao Liu ◽  
Haihao Wu ◽  
...  
Keyword(s):  
Finite Element ◽  
Range Of Motion ◽  
Facet Joint ◽  
Adjacent Segment ◽  
Finite Element Models ◽  
Level Of Evidence ◽  
Element Analysis ◽  
Flexion Extension ◽  
Biomechanical Effect ◽  
Lumbar Range Of Motion

Abstract Background The superior facet arthroplasty is important for intervertebral foramen microscopy. To our knowledge, there is no study about the postoperative biomechanics of adjacent L4/L5 segments after different methods of S1 superior facet arthroplasty. To evaluate the effect of S1 superior facet arthroplasty on lumbar range of motion and disc stress of adjacent segment (L4/L5) under the intervertebral foraminoplasty. Methods Eight finite element models (FEMs) of lumbosacral vertebrae (L4/S) had been established and validated. The S1 superior facet arthroplasty was simulated with different methods. Then, the models were imported into Nastran software after optimization; 500 N preload was imposed on the L4 superior endplate, and 10 N⋅m was given to simulate flexion, extension, lateral flexion and rotation. The range of motion (ROM) and intervertebral disc stress of the L4-L5 spine were recorded. Results The ROM and disc stress of L4/L5 increased with the increasing of the proportions of S1 superior facet arthroplasty. Compared with the normal model, the ROM of L4/L5 significantly increased in most directions of motion when S1 superior facet formed greater than 3/5 from the ventral to the dorsal or 2/5 from the apex to the base. The disc stress of L4/L5 significantly increased in most directions of motion when S1 superior facet formed greater than 3/5 from the ventral to the dorsal or 1/5 from the apex to the base. Conclusion In this study, the ROM and disc stress of L4/L5 were affected by the unilateral S1 superior facet arthroplasty. It is suggested that the forming range from the ventral to the dorsal should be less than 3/5 of the S1 upper facet joint. It is not recommended to form from apex to base. Level of evidence Level IV

scholarly journals Difference in patient-reported outcomes of various patellar component designs in total knee arthroplasty: A randomized clinical study

2021 ◽  
Vol 29 (1) ◽  
pp. 230949902199606
Author(s):  
Takeshi Mochizuki ◽  
Koichiro Yano ◽  
Katsunori Ikari ◽  
Ken Okazaki
Keyword(s):  
Knee Osteoarthritis ◽  
Clinical Effects ◽  
Patellar Component ◽  
American College Of Rheumatology ◽  
Randomized Clinical Study ◽  
Component Design ◽  
Patient Reported ◽  
Total Knee ◽  
The Difference ◽  
And Function

Purpose: This study investigated the clinical effects of different patellar components without being affected by the femoral component design in total knee arthritis (TKA) for patients with knee osteoarthritis (OA). Methods: In total, 48 patients with OA who met the criteria of the American College of Rheumatology for OA were enrolled and randomly assigned in a 1:1 ratio to two groups according to the usage of patellar component design for TKA (medialized dome type [dome group] or medialized anatomic type [anatomic group]). To evaluate the clinical outcomes for TKA, knee range of motion (ROM), pain intensity of 0–100 mm visual analog scale (pain VAS), and the Japanese Knee Osteoarthritis Measure (JKOM) score were obtained at baseline and year 1. Results: The difference in knee ROM, pain VAS, or total JKOM score at year 1 was not significant between the dome and anatomic groups ( p = 0.398, 0.733 and 0.536, respectively). Moreover, similar results were obtained for changes in knee ROM, pain VAS, or total JKOM scores from baseline. In both groups, the pain VAS and total JKOM scores were significantly improved at year 1. Conclusion: Both dome and anatomic groups in TKA are significantly effective for pain and function using the JKOM score. However, their efficacy did not differ, according to the JKOM score. Results of this study are rare information focusing on the patellar component design and provide one of the insights into the TKA clinical management.

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