title: Heterogeneity of tibial plateau cartilage in response to a physiological compressive strain rate.
abstract: Knowledge of the extent to which tibial plateau cartilage displays non-uniform mechanical topography under physiologically relevant loading conditions is critical to evaluating the role of biomechanics in knee osteoarthritis. Cartilage explants from 21 tibial plateau sites of eight non-osteoarthritic female cadaveric knees (age: 41-54; BMI: 14-20) were tested in unconfined compression at 100% strain/s. The elastic tangent modulus at 10% strain (E(10%) ) was calculated for each site and averaged over four geographic regions: not covered by meniscus (I); covered by meniscus-anterior (II); covered by meniscus-exterior (III); and covered by meniscus-posterior (IV). A repeated-measures mixed model analysis of variance was used to test for effects of plateau, region, and their interaction on E(10%) . Effect sizes were calculated for each region pair. E(10%) was significantly different (p<0.05) for all regional comparisons, except I-II and III-IV. The regional pattern of variation was consistent across individuals. Moderate to strong effect sizes were evident for regional comparisons other than I-II on the lateral side and III-IV on both sides. Healthy tibial cartilage exhibits significant mechanical heterogeneity that manifests in a common regional pattern across individuals. These findings provide a foundation for evaluating the biomechanical mechanisms of knee osteoarthritis.
authors.affiliation: School of Kinesiology, University of Michigan, Ann Arbor, Michigan 48109, USA. jmden@umich.edu
authors.forename: Jessica M
authors.initials: JM
authors.lastname: Deneweth
authors.forename: Kelly E
authors.initials: KE
authors.lastname: Newman
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Sylvia
authors.forename: Scott G
authors.initials: SG
authors.lastname: McLean
authors.forename: Ellen M
authors.initials: EM
authors.lastname: Arruda
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena / Q000502:physiology; D015992:Body Mass Index; D002102:Cadaver; D002356:Cartilage / Q000502:physiology*; D019245:Compressive Strength / Q000502:physiology*; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000503:physiopathology*; D013314:Stress, Mechanical; D013977:Tibia / Q000502:physiology*; D016474:Weight-Bearing / Q000502:physiology