Femoral neck version affects medial femorotibial loading.

T A Papaioannou,Georgios Digas,E A Magnissalis,Ch Bikos,V Karamoulas

doi:10.1155/2013/328246

T A Papaioannou, Georgios Digas + Show 3 more

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https://doi.org/10.1155/2013/328246

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Journal: ISRN orthopedics	Publication Date: Feb 21, 2013
Citations: 20	License type: CC BY 3.0

Affiliation: General Hospital of Attica

Abstract

The aim of this study was to provide a preliminary evaluation of the possible effect that femoral version may have on the bearing equilibrium conditions developed on the medial tibiofemoral compartment. A digital 3D solid model of the left physiological adult femur was used to create morphological variations of different neck-shaft angles (varus 115, normal 125, and valgus 135 degrees) and version angles (−10, 0, and +10 degrees). By means of finite element modeling and analysis techniques (FEM-FEA), a virtual experiment was executed with the femoral models aligned in a neutral upright position, distally supported on a fully congruent tibial tray and proximally loaded with a vertical only hip joint load of 2800 N. Equivalent stresses and their distribution on the medial compartment were computed and comparatively evaluated. Within our context, the neck-shaft angle proved to be of rather indifferent influence. Reduction of femoral version, however, appeared as the most influencing parameter regarding the tendency of the medial compartment to establish its bearing equilibrium towards posteromedial directions, as a consequence of the corresponding anteroposterior changes of the hip centre over the horizontal tibiofemoral plane. We found a correlation between femoral anteversion and medial tibiofemoral compartment contact pressure. Our findings will be further elucidated by more sophisticated FEM-FEA and by clinical studies that are currently planned.

Highlights

Osteoarthritis at large and especially in the knee joint is believed to be the result of local factors acting within the context of a systemic susceptibility [1, 2].These local factors govern how load is distributed across the articular cartilage
The aim of this study was to provide a preliminary evaluation of the possible effect that femoral version may have on the bearing equilibrium conditions developed on the medial tibiofemoral compartment
We found a correlation between femoral anteversion and medial tibiofemoral compartment contact pressure

Summary

Introduction

Osteoarthritis at large and especially in the knee joint is believed to be the result of local factors acting within the context of a systemic susceptibility [1, 2].These local factors govern how load is distributed across the articular cartilage. It is the distribution of load that confers upon weight bearing joints the ability to bear loads that are several times greater than body weight over a lifetime [3] Because alteration in these local factors may lead to the development of excessive stresses on the joint and cause damage to the articular cartilage, they are receiving increasing attention in studies of the natural history of OA and especially the malalignment and laxity. In a recent cadaveric study by Bretin et al [7], the tibiofemoral joint centre of force measured by intra-articular pressure sensor moved medially with external femoral malrotation caused by medial displacement of the mechanical axis This rotational malalignment would result in abnormal loading of the articular cartilage of the knee [8]

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