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Do the soft tissues located outside tibiofemoral joint have a role in bearing the compressive loads of the joint? An in-vitro study on sheep stifle joints
, Article Gazzetta Medica Italiana Archivio per le Scienze Mediche ; Volume 172, Issue 7-8 , 2013 , Pages 595-601 ; 03933660 (ISSN) ; Rostami, M ; Parnianpour, M ; Jabalameli, M ; Sharif University of Technology
2013
Abstract
Aim. The compressive loads on the tibiofemoral joint are normally assumed to be borne solely via contact and pressing of the cartilage surfaces of tibia and femur. However, recent findings suggest that non-contact load-bearing mechanisms are active in the joint as well. In this context, a non-contact load-bearing mechanism involving soft tissue connections outside the tibiofemoral joint has been hypothesized as well. This paper addresses the validity of this hypothesis and the possible involvement of several soft tissue connections outside the joint. Methods. Sheep stifle (knee) joints were studied in vitro. The specimens were loaded in fixed displacement. Various soft tissues outside the...
P 134 – Absence of the patella has minimal effects on sagittal plane gait parameters
, Article Gait and Posture ; Volume 65 , 2018 , Pages 462-464 ; 09666362 (ISSN) ; Khandan, A ; Arab Baniasad, M ; Darbandi, H ; Vafaei, A. R ; Sharif University of Technology
Elsevier B.V
2018
Abstract
Patella is the latest addition to the animal's skeleton. It's role in normal walking has not been clearly defined. A 9-year-old girl with congenital absence of the patella was assessed using instrumented gait analysis. The results show a tendency for the limb for external rotation, which is more pronounced during swing. We suggest that the role of the patella is mainly to redirect the force of the quadriceps tendon medially. The classically described role, which is to increase the lever arm of the quadriceps tendon, was not confirmed in this study. © 2018 Elsevier B.V
A rigid body spring model to investigate the lateral shift-Restraining force behavior of the patellar
, Article 29th Annual International Conference of IEEE-EMBS, Engineering in Medicine and Biology Society, EMBC'07, Lyon, 23 August 2007 through 26 August 2007 ; 2007 , Pages 4679-4682 ; 05891019 (ISSN) ; 1424407885 (ISBN); 9781424407880 (ISBN) ; Farahmand, F ; Meghdari, A ; Sharif University of Technology
2007
Abstract
Patellar lateral stability was studied using a 2D transverse plane model with deformable articular surfaces. Quadriceps muscles and patellar tendon were considered as strings with predefined forces and lateral and medial retinaculum as tensile springs. Deformation behavior of articular cartilage was modeled by a set of compression springs perpendicular to articular surfaces, based on rigid body spring model method (RBSM). Patellar lateral stability was investigated using restraining force method (the external force required to cause up to 10 mm lateral displacement on patella). The results were in good agreement with experimental reports for normal joint, vastus lateralis and vastus medialis...
Mechanical characterization of the ligaments in subject-specific models of the patellofemoral joint using in vivo laxity tests
, Article Knee ; Volume 26, Issue 6 , 2019 , Pages 1220-1233 ; 09680160 (ISSN) ; Farahmand, F ; Arjmand, N ; Sharif University of Technology
Elsevier B.V
2019
Abstract
Background: The purpose of this study was to propose a methodology for mechanical characterization of the ligaments in subject-specific models of the patellofemoral joint (PFJ) of living individuals. Method: PFJ laxity tests were performed on a healthy volunteer using a specially designed loading apparatus under biplane fluoroscopy. A three-dimensional (3D) parametric model of the PFJ was developed in the framework of the rigid body spring model using the geometrical data acquired from the subject's computed tomography and magnetic resonance images. The stiffness and pre-strains of the medial and lateral PFJ ligaments were characterized using a two-step optimization procedure which minimized...
The effects of trochlear groove geometry on patellofemoral joint stability - A computer model study
, Article Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine ; Volume 222, Issue 1 , 2008 , Pages 75-88 ; 09544119 (ISSN) ; Farahmand, F ; Meghdari, A ; Sharif University of Technology
2008
Abstract
The effect of the variation in the femoral groove geometry on patellofemoral joint stability was studied using a two dimensional transverse plane model with deformable articular surfaces. The femoral and patellar bony structures were modelled as rigid bodies with their profiles expressed by splines. The articular cartilage was discretized into compression springs, distributed along the femoral and patellar profiles, based on the rigid-body spring model. The medial and lateral retinacula were modelled as linear tensile springs, and the quadriceps muscles and patellar tendon as strings with known tension. The anatomical data were obtained from the transverse plane magnetic resonance images of...
A detailed and validated three dimensional dynamic model of the patellofemoral joint
, Article Journal of Biomechanical Engineering ; Volume 134, Issue 4 , 2012 ; 01480731 (ISSN) ; Farahmand, F ; Jafari, A ; Foumani, M. S ; Sharif University of Technology
2012
Abstract
A detailed 3D anatomical model of the patellofemoral joint was developed to study the tracking, force, contact and stability characteristics of the joint. The quadriceps was considered to include six components represented by 15 force vectors. The patellar tendon was modeled using four bundles of viscoelastic tensile elements. Each of the lateral and medial retinaculum was modeled by a three-bundle nonlinear spring. The femur and patella were considered as rigid bodies with their articular cartilage layers represented by an isotropic viscoelastic material. The geometrical and tracking data needed for model simulation, as well as validation of its results, were obtained from an in vivo...