title: Impact of measurement errors on the determination of the linear modulus of human meniscal attachments.
abstract: For the development of meniscal substitutes and related finite element models it is necessary to know the mechanical properties of the meniscus and its attachments. Measurement errors can falsify the determination of material properties. Therefore the impact of metrological and geometrical measurement errors on the determination of the linear modulus of human meniscal attachments was investigated. After total differentiation the error of the force (+0.10%), attachment deformation (-0.16%), and fibre length (+0.11%) measurements almost annulled each other. The error of the cross-sectional area determination ranged from 0.00%, gathered from histological slides, up to 14.22%, obtained from digital calliper measurements. Hence, total measurement error ranged from +0.05% to -14.17%, predominantly affected by the cross-sectional area determination error. Further investigations revealed that the entire cross-section was significantly larger compared to the load-carrying collagen fibre area. This overestimation of the cross-section area led to an underestimation of the linear modulus of up to -36.7%. Additionally, the cross-sections of the collagen-fibre area of the attachments significantly varied up to +90% along their longitudinal axis. The resultant ratio between the collagen fibre area and the histologically determined cross-sectional area ranged between 0.61 for the posterolateral and 0.69 for the posteromedial ligament. The linear modulus of human meniscal attachments can be significantly underestimated due to the use of different methods and locations of cross-sectional area determination. Hence, it is suggested to assess the load carrying collagen fibre area histologically, or, alternatively, to use the correction factors proposed in this study.
authors.affiliation: Institute of Orthopaedic Research and Biomechanics, Centre of Musculoskeletal Research Ulm, University of Ulm, Germany. andreas.seitz@uni-ulm.de
authors.forename: Andreas Martin
authors.initials: AM
authors.lastname: Seitz
authors.forename: Uwe
authors.initials: U
authors.lastname: Wolfram
authors.forename: Carina
authors.initials: C
authors.lastname: Wiedenmann
authors.forename: Anita
authors.initials: A
authors.lastname: Ignatius
authors.forename: Lutz
authors.initials: L
authors.lastname: Dürselen
mesh_terms: D000368:Aged; D019412:Anatomy, Cross-Sectional; D001696:Biomechanical Phenomena; D003094:Collagen / Q000378:metabolism; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008422:Materials Testing / Q000379:methods*; D055595:Mechanical Phenomena; D008592:Menisci, Tibial / Q000033:anatomy & histology / Q000378:metabolism; D012107:Research Design
chemical_list: D003094:Collagen