A Model for the Function and Failure of the Meniscus

Abstract

The meniscus has been modelled as a toroid of constant wedge-shaped cross-section resting on a compliant base and loaded in compression from above. This simple model allows the cross-sectional shape and the mechanical properties of the fibrocartilage to be varied systematically in order to determine the essential features of the response of the meniscus to compressive load. A finite element representation of this model shows that a circumferential tensile strain is developed, irrespective of the cross-sectional shape or the elastic moduli of the fibrocartilage, to balance the applied load. A horizontal boundary between regions of positive and negative shear strains and a region of radial tensile strain are also developed. These regions coincide with the locations of horizontal and longitudinal tears which are the most commonly observed lesions of the meniscus. The model shows that the posterior segment of the medial meniscus is most vulnerable to injury.