Structure-Function relationships of equine menisci.

Iris Ribitsch,Johannes Peter Schramel,Monika Egerbacher,Claus Vogl,Christian Peham,Florien Jenner,Julia Dürr,Heike Walles,Nicole Ade,Stephan Handschuh,Jose Manuel Garcia Aznar

doi:10.1371/journal.pone.0194052

Abstract

Meniscal pathologies are among the most common injuries of the femorotibial joint in both human and equine patients. Pathological forces and ensuing injuries of the cranial horn of the equine medial meniscus are considered analogous to those observed in the human posterior medial horn. Biomechanical properties of human menisci are site- and depth- specific. However, the influence of equine meniscus topography and composition on its biomechanical properties is yet unknown. A better understanding of equine meniscus composition and biomechanics could advance not only veterinary therapies for meniscus degeneration or injuries, but also further substantiate the horse as suitable translational animal model for (human) meniscus tissue engineering. Therefore, the aim of this study was to investigate the composition and structure of the equine knee meniscus in a site- and age-specific manner and their relationship with potential site-specific biomechanical properties. The meniscus architecture was investigated histologically. Biomechanical testing included evaluation of the shore hardness (SH), stiffness and energy loss of the menisci. The SH was found to be subjected to both age and site-specific changes, with an overall higher SH of the tibial meniscus surface and increase in SH with age. Stiffness and energy loss showed neither site nor age related significant differences. The macroscopic and histologic similarities between equine and human menisci described in this study, support continued research in this field.

Highlights

In accordance with the role menisci play in knee joint function, meniscal injuries are common in athletes and the general population [1]
While comparable meniscal pathology can substantiate the validity of a species as translational animal model [2], the anatomical, physiological and biomechanical properties need to approximate the conditions in humans
In the current paper we focused on the two major matrix components (Col I fibres and GAGs) and the question whether differences in their arrangement, network formation and distribution at regions A, B and C, between medial and lateral menisci and between the three age groups may account for differences in biomechanical properties

Summary

Introduction

In accordance with the role menisci play in knee joint function, meniscal injuries are common in athletes and the general population [1]. The need to improve treatment for meniscal injuries and to identify appropriate translational animal models for meniscus tissue engineering and regenerative repair is of critical importance. The horse (Equus caballus), as one of the few species suffering from naturally occurring meniscus injuries and dysfunction, lends itself for this role as it would serve as an animal model and as a beneficiary of improvements in the treatment. While comparable meniscal pathology can substantiate the validity of a species as translational animal model [2], the anatomical, physiological and biomechanical properties need to approximate the conditions in humans. The anatomy of equine menisci is well known [3, 4],, the histologic composition and biomechanical properties of the equine meniscus still need to be characterized, prior to using the horse as a translational model to study meniscus disorders

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