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

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.

Download Full-text

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

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967120s00523 ◽

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

Download Full-text

Non-operative Care of the Patient with an ACL-Deficient Knee

Current Reviews in Musculoskeletal Medicine ◽

10.1007/s12178-017-9431-6 ◽

2017 ◽

Vol 10 (3) ◽

pp. 322-327 ◽

Cited By ~ 17

Author(s):

Mark V. Paterno

Keyword(s):

Operative Care ◽

Acl Deficient ◽

Deficient Knee

Download Full-text

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

The American Journal of Sports Medicine ◽

10.1177/0363546518802225 ◽

2018 ◽

Vol 47 (1) ◽

pp. 96-103 ◽

Cited By ~ 8

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.

Download Full-text