Forces at the Anterior Meniscus Attachments Strongly Increase Under Dynamic Knee Joint Loading

2021 ◽  
Vol 49 (4) ◽  
pp. 994-1004
Author(s):  
Andreas Martin Seitz ◽  
Florian Schall ◽  
Steffen Paul Hacker ◽  
Stefan van Drongelen ◽  
Sebastian Wolf ◽  
...  
Keyword(s):  
Knee Flexion ◽  
Muscle Force ◽  
Meniscal Tear ◽  
In Vitro Tests ◽  
Jump Landing ◽  
Medial Meniscectomy ◽  
Attachment Structures ◽  
Flexion Extension ◽  
Longitudinal Tear

Background: The anatomic appearance and biomechanical and clinical importance of the anterior meniscus roots are well described. However, little is known about the loads that act on these attachment structures under physiological joint loads and movements. Hypotheses: As compared with uniaxial loading conditions under static knee flexion angles or at very low flexion-extension speeds, more realistic continuous movement simulations in combination with physiological muscle force simulations lead to significantly higher anterior meniscus attachment forces. This increase is even more pronounced in combination with a longitudinal meniscal tear or after total medial meniscectomy. Study Design: Controlled laboratory study. Methods: A validated Oxford Rig–like knee simulator was used to perform a slow squat, a fast squat, and jump landing maneuvers on 9 cadaveric human knee joints, with and without muscle force simulation. The strains in the anterior medial and lateral meniscal periphery and the respective attachments were determined in 3 states: intact meniscus, medial longitudinal tear, and total medial meniscectomy. To determine the attachment forces, a subsequent in situ tensile test was performed. Results: Muscle force simulation resulted in a significant strain increase at the anterior meniscus attachments of up to 308% ( P < .038) and the anterior meniscal periphery of up to 276%. This corresponded to significantly increased forces ( P < .038) acting in the anteromedial attachment with a maximum force of 140 N, as determined during the jump landing simulation. Meniscus attachment strains and forces were significantly influenced ( P = .008) by the longitudinal tear and meniscectomy during the drop jump simulation. Conclusion: Medial and lateral anterior meniscus attachment strains and forces were significantly increased with physiological muscle force simulation, corroborating our hypothesis. Therefore, in vitro tests applying uniaxial loads combined with static knee flexion angles or very low flexion-extension speeds appear to underestimate meniscus attachment forces. Clinical Relevance: The data of the present study might help to optimize the anchoring of meniscal allografts and artificial meniscal substitutes to the tibial plateau. Furthermore, this is the first in vitro study to indicate reasonable minimum stability requirements regarding the reattachment of torn anterior meniscus roots.

scholarly journals Patellofemoral kinematics during knee flexion-extension: An in vitro study

2006 ◽  
Vol 24 (12) ◽  
pp. 2201-2211 ◽  
Author(s):  
Andrew A. Amis ◽  
Wongwit Senavongse ◽  
Anthony M. J. Bull
Keyword(s):  
Knee Flexion ◽  
In Vitro Study ◽  
Vitro Study ◽  
Flexion Extension ◽  
Patellofemoral Kinematics

In Vitro Kinematic Analysis of Single Axis Radius Posterior-Substituting Total Knee Arthroplasty

2020 ◽  
Author(s):  
Paul Arauz ◽  
Yun Peng ◽  
Tiffany Castillo ◽  
Christian Klemt ◽  
Young-Min Kwon
Keyword(s):  
Knee Flexion ◽  
Knee Kinematics ◽  
Lateral Collateral Ligament ◽  
Collateral Ligament ◽  
Flexion Extension ◽  
Healthy Knee ◽  
Joint Biomechanics ◽  
Total Knee ◽  
Intact Knee

AbstractThis is an experimental study. As current posterior-substituting (PS) total knee arthroplasties have been reported to incompletely restore intrinsic joint biomechanics of the healthy knee, the recently designed single axis radius PS knee system was introduced to increase posterior femoral translation and promote ligament isometry. As there is a paucity of data available regarding its ability to replicate healthy knee biomechanics, this study aimed to assess joint and articular contact kinematics as well as ligament isometry of the contemporary single axis radius PS knee system. Implant kinematics were measured from 11 cadaveric knees using an in vitro robotic testing system. In addition, medial collateral ligament (MCL) and lateral collateral ligament (LCL) forces were quantified under simulated functional loads during knee flexion for the contemporary PS knee system. Posterior femoral translation between the intact knee and the single axis radius PS knee system differed significantly (p < 0.05) at 60, 90, and 120 degrees of flexion. The LCL force at 60 degrees (9.06 ± 2.81 N) was significantly lower (p < 0.05) than those at 30, 90, and 120 degrees of flexion, while MCL forces did not differ significantly throughout the range of tested flexion angles. The results from this study suggest that although the contemporary single axis radius PS knee system has the potential to mimic the intact knee kinematics under muscle loading during flexion extension due to its design features, single axis radius PS knee system did not fully replicate posterior femoral translation and ligament isometry of the healthy knee during knee flexion.

scholarly journals Numerical Modelling of the Behaviour of the Cervical Spine under the Effect of a Flexion / Extension

2019 ◽  
Vol 01 (02) ◽  
pp. 144-153 ◽  
Author(s):  
Nadir Damba ◽  
Abdellatif OUDRANE ◽  
Benaoumeur AOUR ◽  
Mohammed Salah BENNOUNA ◽  
Nabil BELKAHELLA ◽  
...  
Keyword(s):  
Cervical Spine ◽  
Classical Mechanics ◽  
Three Dimensional ◽  
Individual Variability ◽  
In Vitro Tests ◽  
Three Dimensional Model ◽  
Major Interest ◽  
Flexion Extension

Numerical simulation is today widely used in several fields of engineering, and research undertaken for more than 20 years concerning the geometric and mechanical modeling of the spine gradually leads to clinical applications of major interest. Indeed, the in vivo and in vitro evaluation tools pose a certain number of limitations: non-standardized procedures and inter-specimen variability for in vitro tests, medical, ethical constraints, and inter-individual variability for in vivo. These limitations are actually obstacles to comparison. It is notably within the framework of implant comparisons that the methods of structural calculation, and more particularly finite element modeling, widely used in classical mechanics, find their usefulness. in this context, this present work consists in developing a three-dimensional model of the cervical spine, in order to subsequently optimize the fitting of disc prostheses

Anti-Diabetic Activity of a Mineraloid Isolate, in vitro and in Genetically Diabetic Mice

2011 ◽  
Vol 81 (1) ◽  
pp. 34-42 ◽  
Author(s):  
Joel Deneau ◽  
Taufeeq Ahmed ◽  
Roger Blotsky ◽  
Krzysztof Bojanowski
Keyword(s):  
Dna Microarrays ◽  
Human Fibroblasts ◽  
Diabetic Animal ◽  
In Vitro Tests ◽  
Diabetic Mice ◽  
Fossil Material ◽  
Expression Of Genes ◽  
Enhanced Expression ◽  
Genetically Diabetic Mice

Type II diabetes is a metabolic disease mediated through multiple molecular pathways. Here, we report anti-diabetic effect of a standardized isolate from a fossil material - a mineraloid leonardite - in in vitro tests and in genetically diabetic mice. The mineraloid isolate stimulated mitochondrial metabolism in human fibroblasts and this stimulation correlated with enhanced expression of genes coding for mitochondrial proteins such as ATP synthases and ribosomal protein precursors, as measured by DNA microarrays. In the diabetic animal model, consumption of the Totala isolate resulted in decreased weight gain, blood glucose, and glycated hemoglobin. To our best knowledge, this is the first description ever of a fossil material having anti-diabetic activity in pre-clinical models.

Cardiovascular and Metabolic Responses to Electrical Stimulation-Induced Leg Exercise in Spinal Cord Injury

1997 ◽  
Vol 36 (04/05) ◽  
pp. 372-375 ◽  
Author(s):  
J. R. Sutton ◽  
A. J. Thomas ◽  
G. M. Davis
Keyword(s):  
Spinal Cord ◽  
Heart Rate ◽  
Spinal Cord Injury ◽  
Cardiac Output ◽  
Electrical Stimulation ◽  
Knee Flexion ◽  
Flexion Extension ◽  
Cord Injury ◽  
Leg Exercise ◽  
Leg Muscle

Abstract:Electrical stimulation-induced leg muscle contractions provide a useful model for examining the role of leg muscle neural afferents during low-intensity exercise in persons with spinal cord-injury and their able-bodied cohorts. Eight persons with paraplegia (SCI) and 8 non-disabled subjects (CONTROL) performed passive knee flexion/extension (PAS), electrical stimulation-induced knee flexion/extension (ES) and voluntary knee flexion/extension (VOL) on an isokinetic dynamometer. In CONTROLS, exercise heart rate was significantly increased during ES (94 ± 6 bpm) and VOL (85 ± 4 bpm) over PAS (69 ± 4 bpm), but no changes were observed in SCI individuals. Stroke volume was significantly augmented in SCI during ES (59 ± 5 ml) compared to PAS (46 ± 4 ml). The results of this study suggest that, in able-bodied humans, Group III and IV leg muscle afferents contribute to increased cardiac output during exercise primarily via augmented heart rate. In contrast, SCI achieve raised cardiac output during ES leg exercise via increased venous return in the absence of any change in heart rate.

Comparison of High Purity Factor IX Concentrates and a Prothrombin Complex Concentrate in a Canine Model of Thrombogenicity

1991 ◽  
Vol 66 (05) ◽  
pp. 609-613 ◽  
Author(s):  
I R MacGregor ◽  
J M Ferguson ◽  
L F McLaughlin ◽  
T Burnouf ◽  
C V Prowse
Keyword(s):  
High Purity ◽  
Time Course ◽  
Prothrombin Complex Concentrate ◽  
Degradation Products ◽  
Canine Model ◽  
Factor Ix ◽  
In Vitro Tests ◽  
Albumin Infusion

SummaryA non-stasis canine model of thrombogenicity has been used to evaluate batches of high purity factor IX concentrates from 4 manufacturers and a conventional prothrombin complex concentrate (PCC). Platelets, activated partial thromboplastin time (APTT), fibrinogen, fibrin(ogen) degradation products and fibrinopeptide A (FPA) were monitored before and after infusion of concentrate. Changes in FPA were found to be the most sensitive and reproducible indicator of thrombogenicity after infusion of batches of the PCC at doses of between 60 and 180 IU/kg, with a dose related delayed increase in FPA occurring. Total FPA generated after 100-120 IU/kg of 3 batches of PCC over the 3 h time course was 9-12 times that generated after albumin infusion. In contrast the amounts of FPA generated after 200 IU/kg of the 4 high purity factor IX products were in all cases similar to albumin infusion. It was noted that some batches of high purity concentrates had short NAPTTs indicating that current in vitro tests for potential thrombogenicity may be misleading in predicting the effects of these concentrates in vivo.

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