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.

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.

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.

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 Bone Cement Solidifiliation Influence the Limb Alignment and Gap Balance during TKA

2015 ◽  
Vol 2015 ◽  
pp. 1-3 ◽  
Author(s):  
Dongquan Shi ◽  
Xingquan Xu ◽  
Anyun Guo ◽  
Jin Dai ◽  
Zhihong Xu ◽  
...  
Keyword(s):  
Total Knee Arthroplasty ◽  
Bone Cement ◽  
Knee Arthroplasty ◽  
Mechanical Axis ◽  
Statistical Significance ◽  
Mechanical Alignment ◽  
Early Loosening ◽  
Flexion Extension ◽  
Before And After ◽  
Total Knee

Introduction. Mechanical alignment deviation after total knee arthroplasty is a major reason for early loosening of the prosthesis. Achieving optimum cement penetration during fixation of the femoral and tibial component is an essential step in performing a successful total knee arthroplasty. Bone cement is used to solidify the bone and prosthesis. Thickness imbalance of bone cement leads to the deviation of mechanical alignment. To estimate the influence of bone cement, a retrospective study was conducted.Materials and Methods. A total of 36 subjects were studied. All the TKA were performed following the standard surgical protocol for navigated surgery by medial approach with general anaesthesia. Prostheses were fixed by bone cement.Results. We compared the mechanical axis, flexion/extension, and gap balance before and after cementation. All the factors were different compared with those before and after cementation. Internal rotation was reached with statistical significance (P=0.03).Conclusion. Bone cement can influence the mechanical axis, flexion/extension, and gap balance. It also can prompt us to make a change when poor knee kinematics were detected before cementation.

Continuous Passive Motion Not Affect the Knee Motion and the Surgical wound Aspect After Total Knee Arthroplasty

2021 ◽  
Author(s):  
Sergi Gil-Gonzalez ◽  
Ricardo Andrés Barja Rodriguez ◽  
Antoni Lopez Pujol ◽  
Hussein Berjaoui ◽  
Jose Enrique Fernandez Bengoa ◽  
...  
Keyword(s):  
Total Knee Arthroplasty ◽  
Range Of Motion ◽  
Knee Arthroplasty ◽  
Continuous Passive Motion ◽  
Surgical Wound ◽  
Knee Motion ◽  
Passive Motion ◽  
Significant Difference ◽  
Flexion Extension ◽  
Total Knee

Abstract Background. This study aimed to assess whether use of continuous passive motion (CPM) can improve range of motion in patients after total knee arthroplasty (TKA). Moreover, the relationship between the use of CPM with the surgical wound aspect (SWA) and pain management after TKA was analysed.Methods. We randomized 210 patients, 102 patients in the CPM group, who received a standard rehabilitation protocol together with CPM application; and 108 patients in the no-CPM group, without CPM. Variables as knee motion (flexion, extension, range of motion) and pain was measured before surgery, on the 1s, 2nd and 3rd postoperative day, and in the 2nd, 6th, 12th and 24th postoperative weeks following TKA. The SWA was determined by the “surgical wound aspect score” (SWAS) in the next 48 hours after surgery. This scale analyses swelling, erythema, haematoma, blood drainage and blisters. Results. There was an improvement in the knee motion over the course of follow-up in both groups, without significant difference in flexion parameter. We found no significant differences in the total score of SWA, except for haematoma, with less severity in the CPM group. Furthermore, we found no differences in the others SWAS parameters and pain. Conclusions. The application of CPM does not provide benefit to our patients undergoing TKA in terms of either improved flexion mobility or decreased pain. No relationship was found between the use of CPM and the global score of SWA following a TKA, except for a decrease in haematoma appearance.

scholarly journals Finite-element analysis of the proximal tibial sclerotic bone and different alignment in total knee arthroplasty

2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Ye-Ran Li ◽  
Yu-Hang Gao ◽  
Chen Yang ◽  
Lu Ding ◽  
Xuebo Zhang ◽  
...  
Keyword(s):  
Finite Element ◽  
Total Knee Arthroplasty ◽  
Knee Arthroplasty ◽  
Tibial Plateau ◽  
Three Dimensional ◽  
Genu Varum ◽  
Sclerotic Bone ◽  
Dimensional Measurements ◽  
Tibial Cut ◽  
Total Knee

Abstract Background Despite potential for improving patient outcomes, studies using three-dimensional measurements to quantify proximal tibial sclerotic bone and its effects on prosthesis stability after total knee arthroplasty (TKA) are lacking. Therefore, this study aimed to determine: (1) the distribution range of tibial sclerotic bone in patients with severe genu varum using three-dimensional measurements, (2) the effect of the proximal tibial sclerotic bone thickness on prosthesis stability according to finite-element modelling of TKA with kinematic alignment (KA), mechanical alignment (MA), and 3° valgus alignment, and (3) the effect of short extension stem augment utilization on prosthesis stability. Methods The sclerotic bone in the medial tibial plateau of 116 patients with severe genu varum was measured and classified according to its position and thickness. Based on these cases, finite-element models were established to simulate 3 different tibial cut alignments with 4 different thicknesses of the sclerotic bone to measure the stress distribution of the tibia and tibial prosthesis, the relative micromotion beneath the stem, and the influence of the short extension stem on stability. Results The distribution range of proximal tibial sclerotic bone was at the anteromedial tibial plateau. The models were divided into four types according to the thickness of the sclerotic bone: 15 mm, 10 mm, 5 mm, and 0 mm. The relative micromotion under maximum stress was smallest after MA with no sclerotic bone (3241 μm) and largest after KA with 15 mm sclerotic bone (4467 μm). Relative micromotion was largest with KA and smallest with MA in sclerotic models with the same thickness. Relative micromotion increased as thickness of the sclerotic bone increased with KA and MA (R = 0.937, P = 0.03 and R = 0.756, P = 0.07, respectively). Relative micromotion decreased with short extension stem augment in the KA model when there was proximal tibial sclerotic bone. Conclusions The influence of proximal tibial sclerotic bone on prosthesis’s stability is significant, especially with KA tibial cut. Tibial component’s short extension stem augment can improve stability.

scholarly journals The Effect of Knee Flexion Angle on Contact Stress of Total Knee Arthroplasty

2018 ◽  
Vol 225 ◽  
pp. 03009 ◽  
Author(s):  
N.M.A. Azam ◽  
Rosdi Daud ◽  
H. Mas Ayu ◽  
J. Ramli ◽  
M.F.B. Hassan ◽  
...  
Keyword(s):  
Finite Element ◽  
Total Knee Arthroplasty ◽  
Contact Stress ◽  
Knee Arthroplasty ◽  
Maximum Stress ◽  
Flexion Angle ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Current Design ◽  
Total Knee

The effect of flexion angle on contact stress of the knee joint still open to the debate since lack of proof shown that flexion angles does effect the contact stress of Total Knee Arthroplasty (TKA). Thus the aim of this study is to investigate the effect of different flexion angle on contact stress of TKA via finite element method. The TKA is simulated using ANSYS Workbench and the applied loads are 2200 N, 3200 N and 2800 N. The Finite element Analysis (FEA) results for maximum stress of current and proposed designed were then compared. For the new proposed design, the maximum stress for 15° is 12.2 MPa, 45° is 23.6 MPa and 60° is 22.5 MPa which is lower than current design. Thus, it can be concluded that the new proposed design better than current design in term of contact stress. While, the different flexion angle do gives an impact on the performance of the TKA.

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