scholarly journals Restoration of normal knee kinematics with respect to tibial insert design in mobile bearing lateral unicompartmental arthroplasty using computational simulation

2020 ◽  
Vol 9 (7) ◽  
pp. 421-428
Author(s):  
Yong-Gon Koh ◽  
Jin-Ah Lee ◽  
Hyun-Seok Chung ◽  
Hyo-Jeong Kim ◽  
Kyoung-Tak Kang
Keyword(s):  
Internal Rotation ◽  
Computational Simulation ◽  
Knee Kinematics ◽  
Mobile Bearing ◽  
High Rate ◽  
Inferior Surface ◽  
Normal Knee ◽  
Tibial Insert ◽  
Femoral Rollback

Aims Mobile-bearing unicompartmental knee arthroplasty (UKA) with a flat tibial plateau has not performed well in the lateral compartment, leading to a high rate of dislocation. For this reason, the Domed Lateral UKA with a biconcave bearing was developed. However, medial and lateral tibial plateaus have asymmetric anatomical geometries, with a slightly dished medial and a convex lateral plateau. Therefore, the aim of this study was to evaluate the extent at which the normal knee kinematics were restored with different tibial insert designs using computational simulation. Methods We developed three different tibial inserts having flat, conforming, and anatomy-mimetic superior surfaces, whereas the inferior surface in all was designed to be concave to prevent dislocation. Kinematics from four male subjects and one female subject were compared under deep knee bend activity. Results The conforming design showed significantly different kinematics in femoral rollback and internal rotation compared to that of the intact knee. The flat design showed significantly different kinematics in femoral rotation during high flexion. The anatomy-mimetic design preserved normal knee kinematics in femoral rollback and internal rotation. Conclusion The anatomy-mimetic design in lateral mobile UKA demonstrated restoration of normal knee kinematics. Such design may allow achievement of the long sought normal knee characteristics post-lateral mobile UKA. However, further in vivo and clinical studies are required to determine whether this design can truly achieve a more normal feeling of the knee and improved patient satisfaction. Cite this article: Bone Joint Res 2020;9(7):421–428.

scholarly journals Reduction in tibiofemoral conformity in lateral unicompartmental knee arthroplasty is more representative of normal knee kinematics

2019 ◽  
Vol 8 (12) ◽  
pp. 593-600 ◽  
Author(s):  
Yong-Gon Koh ◽  
Jin-Ah Lee ◽  
Hwa-Yong Lee ◽  
Hyo-Jeong Kim ◽  
Hyun-Seok Chung ◽  
...  
Keyword(s):  
Internal Rotation ◽  
Femoral Component ◽  
Knee Arthroplasty ◽  
Unicompartmental Knee Arthroplasty ◽  
Tibial Plateau ◽  
Knee Kinematics ◽  
Lateral Tibial Plateau ◽  
Unicompartmental Knee ◽  
Tibial Insert ◽  
Femoral Rollback

Aims Commonly performed unicompartmental knee arthroplasty (UKA) is not designed for the lateral compartment. Additionally, the anatomical medial and lateral tibial plateaus have asymmetrical geometries, with a slightly dished medial plateau and a convex lateral plateau. Therefore, this study aims to investigate the native knee kinematics with respect to the tibial insert design corresponding to the lateral femoral component. Methods Subject-specific finite element models were developed with tibiofemoral (TF) and patellofemoral joints for one female and four male subjects. Three different TF conformity designs were applied. Flat, convex, and conforming tibial insert designs were applied to the identical femoral component. A deep knee bend was considered as the loading condition, and the kinematic preservation in the native knee was investigated. Results The convex design, the femoral rollback, and internal rotation were similar to those of the native knee. However, the conforming design showed a significantly decreased femoral rollback and internal rotation compared with that of the native knee (p < 0.05). The flat design showed a significant difference in the femoral rollback; however, there was no difference in the tibial internal rotation compared with that of the native knee. Conclusion The geometry of the surface of the lateral tibial plateau determined the ability to restore the rotational kinematics of the native knee. Surgeons and implant designers should consider the geometry of the anatomical lateral tibial plateau as an important factor in the restoration of native knee kinematics after lateral UKA. Cite this article: Bone Joint Res 2019;8:593–600.

Knee kinematics after cruciate retaining highly congruent mobile bearing total knee arthroplasty: An in vivo dynamic RSA study

The Knee ◽  
2020 ◽  
Vol 27 (2) ◽  
pp. 341-347 ◽  
Author(s):  
Umberto Cardinale ◽  
Laura Bragonzoni ◽  
Marco Bontempi ◽  
Domenico Alesi ◽  
Tommaso Roberti di Sarsina ◽  
...  
Keyword(s):  
Total Knee Arthroplasty ◽  
Knee Arthroplasty ◽  
Knee Kinematics ◽  
Mobile Bearing ◽  
Cruciate Retaining ◽  
Total Knee

scholarly journals Patient-specific resurfacing implant knee surgery in subjects with early osteoarthritis results in medial pivot and lateral femoral rollback during flexion: a retrospective pilot study

2021 ◽  
Author(s):  
Philippe Moewis ◽  
René Kaiser ◽  
Adam Trepczynski ◽  
Christoph von Tycowicz ◽  
Leonie Krahl ◽  
...  
Keyword(s):  
Knee Arthroplasty ◽  
External Rotation ◽  
Knee Kinematics ◽  
Axial Rotation ◽  
Patient Specific ◽  
Post Surgery ◽  
Flexion Extension ◽  
Medial Pivot ◽  
Femoral Rollback

Abstract Purpose Metallic resurfacing implants have been developed for the treatment of early, small, condylar and trochlear osteoarthritis (OA) lesions. They represent an option for patients who do not fulfill the criteria for unicompartmental knee arthroplasty (UKA) or total knee arthroplasty (TKA) or are too old for biological treatment. Although clinical evidence has been collected for different resurfacing types, the in vivo post-operative knee kinematics remain unknown. The present study aims to analyze the knee kinematics in subjects with patient-specific episealer implants. This study hypothesized that patient-specific resurfacing implants would lead to knee kinematics close to healthy knees, resulting in medial pivot and a high degree of femoral rollback during flexion. Methods Retrospective study design. Fluoroscopic analysis during unloaded flexion–extension and loaded lunge was conducted at > 12 months post-surgery in ten episealer knees, and compared to ten healthy knees. Pre- and post-operative clinical data of the episealer knees were collected using a visual analog scale (VAS), the EQ 5d Health, and the Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaires. Results A consistent medial pivot was observed in both episealer and healthy knees. Non-significant differences were found in the unloaded (p = 0.15) and loaded (p = 0.51) activities. Although lateral rollback was observed in both groups, it was significantly higher for the episealer knees in both the unloaded (p = 0.02) and loaded (p = 0.01) activities. Coupled axial rotation was significantly higher in the unloaded (p = 0.001) but not in the loaded (p = 0.06) activity in the episealer knees. Improved scores were observed at 1-year post-surgery in the episealer subjects for the VAS (p = 0.001), KOOS (p = 0.001) and EQ Health (p = 0.004). Conclusion At 12 month follow-up, a clear physiological knee kinematics pattern of medial pivot, lateral femoral rollback and coupled axial external femoral rotation during flexion was observed in patients treated with an episealer resurfacing procedure. However, higher femoral rollback and axial external rotation in comparison to healthy knees was observed, suggesting possible post-operative muscle weakness and consequent insufficient stabilization at high flexion.

scholarly journals Dynamic activity dependence of in vivo normal knee kinematics

2008 ◽  
Vol 26 (4) ◽  
pp. 428-434 ◽  
Author(s):  
Taka-aki Moro-oka ◽  
Satoshi Hamai ◽  
Hiromasa Miura ◽  
Takeshi Shimoto ◽  
Hidehiko Higaki ◽  
...  
Keyword(s):  
Knee Kinematics ◽  
Dynamic Activity ◽  
Normal Knee ◽  
Activity Dependence

scholarly journals In Vivo Normal Knee Kinematics: Is Ethnicity or Gender an Influencing Factor?

2010 ◽  
Vol 469 (1) ◽  
pp. 95-106 ◽  
Author(s):  
Filip Leszko ◽  
Kristen R. Hovinga ◽  
Amy L. Lerner ◽  
Richard D. Komistek ◽  
Mohamed R. Mahfouz
Keyword(s):  
Influencing Factor ◽  
Knee Kinematics ◽  
Normal Knee

scholarly journals Loss of Knee Flexion and Femoral Rollback of the Medial-Pivot and Posterior-Stabilized Total Knee Arthroplasty During Early-Stance of Walking in Chinese Patients

2021 ◽  
Vol 9 ◽  
Author(s):  
Jiaqi Tan ◽  
Diyang Zou ◽  
Xianlong Zhang ◽  
Nan Zheng ◽  
Yuqi Pan ◽  
...  
Keyword(s):  
Total Knee Arthroplasty ◽  
Patient Satisfaction ◽  
Knee Flexion ◽  
Knee Kinematics ◽  
Chinese Patients ◽  
Posterior Stabilized ◽  
Medial Pivot ◽  
Total Knee ◽  
Femoral Rollback

Background The medial-pivot (MP) prosthesis was developed to produce more physiological postoperative knee kinematics and better patient satisfaction than traditional prostheses, but outcomes are inconsistent in different studies of Caucasian patients. This study aimed to investigate the postoperative patient satisfaction and in vivo knee kinematics of the MP and posterior-stabilized (PS) prosthesis during gait activity in Chinese patients.Methods A retrospective analysis of 12 patients was received for this study in each MP group and PS group. Patient-reported satisfaction level and Forgotten Joint Score (FJS) were evaluated with questionnaires. A dual fluoroscopic imaging system was used to investigate in vivo knee kinematics of MP and PS total knee arthroplasty (TKA) during treadmill walking at a speed of 0.4 m/s.Results Comparable promising patient satisfaction and overall FJS (MP 60.7 ± 15.35 vs. PS 51.3 ± 17.62, p = 0.174) were found between the MP and PS groups. Peak flexion appeared at around 70% of gait cycle with values of 52.4 ± 7.4° for MP and 50.1 ± 3.6° for PS groups (no difference). Both groups maintained a stable position at the stance phase and began to translated anteriorly at toe-off with an amount of 4.5 ± 2.3 mm in the MP and 6.6 ± 2.7 mm in the PS (p = 0.08) group until late swing. The range of this external rotation motion was 5.9 ± 4.8 and 6.2 ± 4.1° (p = 0.79) for the MP and PS, respectively.Conclusion A similar knee kinematics pattern characterized by a loss of early-stance knee flexion and femoral rollback during walking was observed in the MP and PS TKAs. Our study confirmed similar effectiveness of MP TKA compared to PS TKA in Chinese patients, while the change of knee kinematics of both implants during slow walking should be noted.

Higher Axial Tibiofemoral Rotation and Functional Outcomes with Mobile-Bearing Compared with Fixed-Bearing Total Knee Arthroplasty at 1- but Not at 2-Year Follow-Up—A Randomized Clinical Trial

2019 ◽  
Vol 33 (05) ◽  
pp. 474-480
Author(s):  
Joicemar Tarouco Amaro ◽  
João Victor Novaretti ◽  
Diego Costa Astur ◽  
Elton Luiz Batista Cavalcante ◽  
Adilson Góes Rodrigues Junior ◽  
...  
Keyword(s):  
Clinical Outcomes ◽  
Functional Outcomes ◽  
Knee Kinematics ◽  
Mobile Bearing ◽  
Fixed Bearing ◽  
Tibiofemoral Rotation ◽  
Total Knee ◽  
In Vivo Knee Kinematics

AbstractThe objective of this study was to determine in vivo knee kinematics and clinical outcomes of patients who underwent fixed- and mobile-bearing total knee arthroplasty (TKA) at 1- and 2-year follow-up. This prospective double-blinded randomized controlled trial was performed from November 2011 to December 2012. A total of 64 patients were randomized to fixed- and mobile-bearing TKA groups (32 patients in each group). All patients were evaluated with the following: three-dimensional in vivo knee kinematics analysis during gait, stepping up and stepping down stair steps, and getting up from and sitting on a chair; and knee range of motion and patient-reported outcome measures (Knee Outcome Survey Activities of Daily Living Scale [KOS-ADLS] and pain visual analog scale [VAS]) at 1- and 2-year follow-up. Descriptive statistics (means, standard deviations, and percentages) were calculated for all variables. The Kolmogorov–Smirnov test was used to test if variables were normally distributed. A Student's t-test was used to compare continuous variables between patients in the two groups. The chi-square test was used to compare the groups with respect to categorical variables. The α level for statistical significance was set at p < 0.05. The mean axial tibiofemoral rotation in patients who underwent mobile-bearing TKA was significantly higher during gait (13.3 vs. 10.7), stepping up (12.8 vs. 10) stair steps, and getting up (16.1 vs. 12.1) from a chair compared with fixed-bearing TKA patients at 1-year follow-up (p < 0.05). KOS-ADLS function score was significantly higher in the mobile-bearing compared with the fixed-bearing TKA group (32 vs. 27.7) at 1-year follow-up (p < 0.05). No significant difference in kinematics and clinical outcomes between fixed- and mobile-bearing TKA groups was observed at 2-year follow-up (p > 0.05). Based on the results of this study, mobile-bearing TKA allowed a higher degree of rotation when walking, stepping up stair steps, and standing up from a chair, and had higher functional outcomes compared with fixed-bearing TKA at 1-year follow-up. However, no difference in in vivo kinematics or in clinical outcomes was observed between fixed- and mobile-bearing prostheses at 2-year follow-up.

scholarly journals Effects of a 1-mm Difference in Bearing Thickness on Intraoperative Bearing Movement and Kinematics in Oxford Unicompartmental Knee Arthroplasty 

2021 ◽  
Author(s):  
Kohei Kawaguchi ◽  
Hiroshi Inui ◽  
Shuji Taketomi ◽  
Ryota Yamagami ◽  
Kenichi Kono ◽  
...  
Keyword(s):  
Internal Rotation ◽  
Knee Arthroplasty ◽  
Unicompartmental Knee Arthroplasty ◽  
Knee Kinematics ◽  
Mobile Bearing ◽  
The Other ◽  
Tibial Internal Rotation ◽  
Unicompartmental Knee ◽  
Valgus Correction Angle ◽  
Oxford Unicompartmental Knee Arthroplasty

Abstract Background: The choice of mobile bearing (MB) thickness is essential for obtaining successful results after mobile-bearing Oxford unicompartmental knee arthroplasty (UKA). This study aimed to investigate the effects of a 1-mm difference in bearing thickness on intraoperative MB movement and intraoperative knee kinematics in Oxford UKAs.Methods: We prospectively investigated the intraoperative MB movement and knee kinematics of 25 patients who underwent Oxford UKAs when surgeons didn’t know which bearing thickness to choose with 1-mm difference. A trial tibial component that was scaled every 2 mm was used to measure the intraoperative MB movement, and the tibial internal rotation relative to the femur and the knee varus angle was simultaneously evaluated using the navigation system as the knee kinematics. We separately evaluated sets of two MB thicknesses with 1-mm differences, and we compared the intraoperative parameters at maximum extension; 30º, 45º, 60º, and 90º flexion; and maximum flexion between the thicker MB (thick group) and the thinner MB (thin group).Results: The MB in the thin group was located significantly posteriorly at 90º flexion compared with that in the thick group; however, there were no differences at the other flexion angles. There was significantly less tibial internal rotation in the thin group at 90º flexion than that in the thick group; however, there were no differences at the other flexion angles. The knee varus angles in the thick group were significantly smaller than those in the thin group by approximately one degree at all angles other than at 30º and 45º flexion. Conclusion: The thicker MB could bring the less posterior MB movement and the more tibial internal rotation at 90º flexion, additionally the valgus correction angle in the thicker MB should be paid attention. These results could help surgeons to decide the thickness of MBs when they wonder the thickness of MB.

scholarly journals STEM-26. SMALL MOLECULE DRUG CBL0137 INHIBITS THE FACT COMPLEX AND SENSITIZES GLIOBLASTOMA CANCER STEM CELLS TO RADIOTHERAPY

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii201-ii202
Author(s):  
Miranda Tallman ◽  
Abigail Zalenski ◽  
Amanda Deighen ◽  
Morgan Schrock ◽  
Sherry Mortach ◽  
...  
Keyword(s):  
Stem Cells ◽  
Cancer Stem Cells ◽  
High Rate ◽  
Orthotopic Model ◽  
In Vivo Models ◽  
Specific Cytotoxicity ◽  
Treatment Paradigm ◽  
Cancer Agent

Abstract Glioblastoma (GBM) is a malignant brain tumor with nearly universal recurrence. GBM cancer stem cells (CSCs), a subpopulation of radio- and chemo-resistant cancer cells capable of self-renewal, contribute to the high rate of recurrence. The anti-cancer agent, CBL0137, inhibits the FACT (facilitates chromatin transcription) complex leading to cancer cell specific cytotoxicity. Here, we show that CBL0137 sensitized GBM CSCs to radiotherapy using both in vitro and in vivo models. Treatment of CBL0137 combined with radiotherapy led to increased DNA damage in GBM patient specimens and failure to resolve the damage led to decreased cell viability. Using clonogenic assays, we confirmed that CBL0137 radiosensitized the CSCs. To validate that combination therapy impacted CSCs, we used an in vivo subcutaneous model and showed a decrease in the frequency of cancer stem cells present in tumors as well as decreased tumor volume. Using an orthotopic model of GBM, we confirmed that treatment with CBL0137 followed by radiotherapy led to significantly increased survival compared to either treatment alone. Radiotherapy remains a critical component of patient care for GBM, even though there exists a resistant subpopulation. Radio-sensitizing agents, including CBL0137, pose an exciting treatment paradigm to increase the efficacy of irradiation, especially by inclusively targeting CSCs.

scholarly journals Effects of Loading and Boundary Conditions on the Performance of Ultrasound Compressional Viscoelastography: A Computational Simulation Study to Guide Experimental Design

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2590
Author(s):  
Che-Yu Lin ◽  
Ke-Vin Chang
Keyword(s):  
Boundary Conditions ◽  
Simulation Study ◽  
Viscoelastic Properties ◽  
Measurement Accuracy ◽  
Computational Simulation ◽  
Vertical Direction ◽  
Fixation Method ◽  
Element Analysis ◽  
Sample Container

Most biomaterials and tissues are viscoelastic; thus, evaluating viscoelastic properties is important for numerous biomedical applications. Compressional viscoelastography is an ultrasound imaging technique used for measuring the viscoelastic properties of biomaterials and tissues. It analyzes the creep behavior of a material under an external mechanical compression. The aim of this study is to use finite element analysis to investigate how loading conditions (the distribution of the applied compressional pressure on the surface of the sample) and boundary conditions (the fixation method used to stabilize the sample) can affect the measurement accuracy of compressional viscoelastography. The results show that loading and boundary conditions in computational simulations of compressional viscoelastography can severely affect the measurement accuracy of the viscoelastic properties of materials. The measurement can only be accurate if the compressional pressure is exerted on the entire top surface of the sample, as well as if the bottom of the sample is fixed only along the vertical direction. These findings imply that, in an experimental validation study, the phantom design should take into account that the surface area of the pressure plate must be equal to or larger than that of the top surface of the sample, and the sample should be placed directly on the testing platform without any fixation (such as a sample container). The findings indicate that when applying compressional viscoelastography to real tissues in vivo, consideration should be given to the representative loading and boundary conditions. The findings of the present simulation study will provide a reference for experimental phantom designs regarding loading and boundary conditions, as well as guidance towards validating the experimental results of compressional viscoelastography.

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