scholarly journals Sagittal Plane Knee Motion in the ACL-Deficient Knee During Body Weight Shift Exercises on Different Support Surfaces

2006 ◽  
Vol 36 (12) ◽  
pp. 954-962 ◽  
Author(s):  
Joanna Kvist
Keyword(s):  
Body Weight ◽  
Sagittal Plane ◽  
Knee Motion ◽  
Weight Shift ◽  
Support Surfaces ◽  
Acl Deficient ◽  
Deficient Knee

Stresses and Strains in the Medial Meniscus of an ACL Deficient Knee under Anterior Loading: A Finite Element Analysis with Image-Based Experimental Validation

2005 ◽  
Vol 128 (1) ◽  
pp. 135-141 ◽  
Author(s):  
Jiang Yao ◽  
Jason Snibbe ◽  
Michael Maloney ◽  
Amy L. Lerner
Keyword(s):  
Finite Element ◽  
Ex Vivo ◽  
Element Model ◽  
Shear Stresses ◽  
Element Analysis ◽  
Knee Motion ◽  
Tissue Properties ◽  
Meniscal Tissue ◽  
Acl Deficient ◽  
Deficient Knee

The menisci are believed to play a stabilizing role in the ACL-deficient knee, and are known to be at risk for degradation in the chronically unstable knee. Much of our understanding of this behavior is based on ex vivo experiments or clinical studies in which we must infer the function of the menisci from external measures of knee motion. More recently, studies using magnetic resonance (MR) imaging have provided more clear visualization of the motion and deformation of the menisci within the tibio-femoral articulation. In this study, we used such images to generate a finite element model of the medial compartment of an ACL-deficient knee to reproduce the meniscal position under anterior loads of 45, 76, and 107N. Comparisons of the model predictions to boundaries digitized from images acquired in the loaded states demonstrated general agreement, with errors localized to the anterior and posterior regions of the meniscus, areas in which large shear stresses were present. Our model results suggest that further attention is needed to characterize material properties of the peripheral and horn attachments. Although overall translation of the meniscus was predicted well, the changes in curvature and distortion of the meniscus in the posterior region were not captured by the model, suggesting the need for refinement of meniscal tissue properties.

scholarly journals Effect of meniscal root tear on pivot shift test after anterior cruciate ligament-deficient

2020 ◽  
Vol 8 (9_suppl7) ◽  
pp. 2325967120S0052
Author(s):  
Ming Zhou
Keyword(s):  
Pivot Shift ◽  
Cruciate Ligament ◽  
Lateral Meniscus ◽  
Pivot Shift Test ◽  
High Grade ◽  
Posterior Root ◽  
Meniscal Root Tear ◽  
Tibial Translation ◽  
Acl Deficient ◽  
Deficient Knee

Introduction: A review of the literature demonstrates that injury of the lateral meniscus, anterolateral capsule, and iliotibial(IT ) band or small lateral tibial plateau aggravate the instability of knee and contributes to a high-grade pivot shift in the ACL-deficient knee. Hypotheses: The hypothesis was that disruption of posterior root of the lateral meniscus will further destabilize the ACL-deficient knee and simulated a high-grade pivot shift but posterior root of medial meniscal not. Methods: 6 fresh-frozen cadaveric knees was performed the next test in a custom activity simulator.1.Determine the effect of PRLMT on the stability of ACL-deficient knee.In the pivot shift test, ITB force (50, 75, 100, 125, 150, and 175 N), internal rotation moments (1, 2, and 3 N.m),and valgus moments (5 and 7 N.m). tibial translation of front drawer test were performed by applying a 90-N anterior

Anticipatory weight shift between arms when reaching from a crouched posture

2021 ◽  
Author(s):  
Rosemary Gallagher ◽  
Stephaine Perez ◽  
Derek DeLuca ◽  
Isaac L. Kurtzer
Keyword(s):  
Body Weight ◽  
Muscle Activity ◽  
Force Plate ◽  
Vertical Axis ◽  
The Body ◽  
Reaching Movements ◽  
Reactive Control ◽  
Step Initiation ◽  
Weight Shift ◽  
The Many

Reaching movements performed from a crouched body posture require a shift of body weight from both arms to one arm. This situation has remained unexamined despite the analogous load requirements during step initiation and the many studies of reaching from a seated or standing posture. To determine whether the body weight shift involves anticipatory or exclusively reactive control we obtained force plate records, hand kinematics, and arm muscle activity from 11 healthy right-handed participants. They performed reaching movements with their left and right arm in two speed contexts - 'comfortable' and 'as fast as possible' - and two postural contexts - a less stable knees-together posture and more stable knees-apart posture. Weight-shifts involved anticipatory postural actions (APA) by the reaching and stance arms that were opposing in the vertical axis and aligned in the side-to-side axis similar to APAs by the legs for step initiation. Weight-shift APAs were correlated in time and magnitude, present in both speed contexts, more vigorous with the knees placed together, and similar when reaching with the dominant or non-dominant arm. The initial weight-shift was preceded by bursts of muscle activity in the shoulder and elbow extensors (posterior deltoid and triceps lateral) of the reach arm and shoulder flexor (pectoralis major) of the stance arm which indicates their causal role; leg muscles may have indirectly contributed but were not recorded. The strong functional similarity of weight-shift APAs during crouched reaching to human stepping and cats reaching suggests that they are a core feature of posture-movement coordination.

scholarly journals Effects of Anterior Cruciate Ligament Deficiency on Tibiofemoral Cartilage Thickness and Strains in Response to Hopping

2018 ◽  
Vol 47 (1) ◽  
pp. 96-103 ◽  
Author(s):  
E. Grant Sutter ◽  
Betty Liu ◽  
Gangadhar M. Utturkar ◽  
Margaret R. Widmyer ◽  
Charles E. Spritzer ◽  
...  
Keyword(s):  
Cruciate Ligament ◽  
Acl Injury ◽  
Cartilage Thickness ◽  
Intercondylar Notch ◽  
Dynamic Activity ◽  
Acl Deficiency ◽  
Anterior Cruciate ◽  
Acl Deficient ◽  
Deficient Knee

Background: Changes in knee kinematics after anterior cruciate ligament (ACL) injury may alter loading of the cartilage and thus affect its homeostasis, potentially leading to the development of posttraumatic osteoarthritis. However, there are limited in vivo data to characterize local changes in cartilage thickness and strain in response to dynamic activity among patients with ACL deficiency. Purpose/Hypothesis: The purpose was to compare in vivo tibiofemoral cartilage thickness and cartilage strain resulting from dynamic activity between ACL-deficient and intact contralateral knees. It was hypothesized that ACL-deficient knees would show localized reductions in cartilage thickness and elevated cartilage strains. Study Design: Controlled laboratory study. Methods: Magnetic resonance images were obtained before and after single-legged hopping on injured and uninjured knees among 8 patients with unilateral ACL rupture. Three-dimensional models of the bones and articular surfaces were created from the pre- and postactivity scans. The pre- and postactivity models were registered to each other, and cartilage strain (defined as the normalized difference in cartilage thickness pre- and postactivity) was calculated in regions across the tibial plateau, femoral condyles, and femoral cartilage adjacent to the medial intercondylar notch. These measurements were compared between ACL-deficient and intact knees. Differences in cartilage thickness and strain between knees were tested with multiple analysis of variance models with alpha set at P < .05. Results: Compressive strain in the intercondylar notch was elevated in the ACL-deficient knee relative to the uninjured knee. Furthermore, cartilage in the intercondylar notch and adjacent medial tibia was significantly thinner before activity in the ACL-deficient knee versus the intact knee. In these 2 regions, thinning was significantly influenced by time since injury, with patients with more chronic ACL deficiency (>1 year since injury) experiencing greater thinning. Conclusion: Among patients with ACL deficiency, the medial femoral condyle adjacent to the intercondylar notch in the ACL-deficient knee exhibited elevated cartilage strain and loss of cartilage thickness, particularly with longer time from injury. It is hypothesized that these changes may be related to posttraumatic osteoarthritis development. Clinical Relevance: This study suggests that altered mechanical loading is related to localized cartilage thinning after ACL injury.

Implications of the Pivot Shift in the ACL-Deficient Knee

2005 ◽  
Vol &NA; (436) ◽  
pp. 229-236 ◽  
Author(s):  
Zachary Leitze ◽  
Ron E Losee ◽  
Peter Jokl ◽  
Thomas R Johnson ◽  
John A Feagin
Keyword(s):  
Pivot Shift ◽  
Acl Deficient ◽  
Deficient Knee

MCL mechanics in the ACL-deficient knee. An experimental and finite element based study

2006 ◽  
Vol 39 ◽  
pp. S408
Author(s):  
T.J. Lujan ◽  
B.J. Ellis ◽  
B.M. Thompson ◽  
J.A. Weiss
Keyword(s):  
Finite Element ◽  
Acl Deficient ◽  
Deficient Knee

scholarly journals Patient self-demonstration of the anterior drawer test in an ACL deficient knee

2015 ◽  
Vol 2015 (jan23 2) ◽  
pp. bcr2014207516-bcr2014207516
Author(s):  
P. Ellanti ◽  
K. J. Mulhall
Keyword(s):  
Anterior Drawer ◽  
Anterior Drawer Test ◽  
Acl Deficient ◽  
Deficient Knee

The ACL-deficient knee and the prevalence of meniscus and cartilage lesions: a systematic review and meta-analysis (CRD42017076897)

2019 ◽  
Vol 139 (6) ◽  
pp. 819-841 ◽  
Author(s):  
Julian Mehl ◽  
Alexander Otto ◽  
Joshua B. Baldino ◽  
Andrea Achtnich ◽  
Ralph Akoto ◽  
...  
Keyword(s):  
Systematic Review ◽  
Meta Analysis ◽  
Cartilage Lesions ◽  
Acl Deficient ◽  
Deficient Knee ◽  
And Cartilage
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