title: In vivo articular cartilage deformation: noninvasive quantification of intratissue strain during joint contact in the human knee.
abstract: The in vivo measurement of articular cartilage deformation is essential to understand how mechanical forces distribute throughout the healthy tissue and change over time in the pathologic joint. Displacements or strain may serve as a functional imaging biomarker for healthy, diseased, and repaired tissues, but unfortunately intratissue cartilage deformation in vivo is largely unknown. Here, we directly quantified for the first time deformation patterns through the thickness of tibiofemoral articular cartilage in healthy human volunteers. Magnetic resonance imaging acquisitions were synchronized with physiologically relevant compressive loading and used to visualize and measure regional displacement and strain of tibiofemoral articular cartilage in a sagittal plane. We found that compression (of 1/2 body weight) applied at the foot produced a sliding, rigid-body displacement at the tibiofemoral cartilage interface, that loading generated subject- and gender-specific and regionally complex patterns of intratissue strains, and that dominant cartilage strains (approaching 12%) were in shear. Maximum principle and shear strain measures in the tibia were correlated with body mass index. Our MRI-based approach may accelerate the development of regenerative therapies for diseased or damaged cartilage, which is currently limited by the lack of reliable in vivo methods for noninvasive assessment of functional changes following treatment.
authors.affiliation: Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, 47907.
authors.forename: Deva D
authors.initials: DD
authors.lastname: Chan
authors.affiliation: Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, 47907.
authors.forename: Luyao
authors.initials: L
authors.lastname: Cai
authors.affiliation: School of Mechanical Engineering, Purdue University, West Lafayette, IN, 47907.
authors.forename: Kent D
authors.initials: KD
authors.lastname: Butz
authors.affiliation: Departments of Orthopaedic Surgery and Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN, 46202.
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Trippel
authors.affiliation: Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, 47907.|School of Mechanical Engineering, Purdue University, West Lafayette, IN, 47907.
authors.forename: Eric A
authors.initials: EA
authors.lastname: Nauman
authors.affiliation: Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, 47907.|Department of Mechanical Engineering, University of Colorado, Boulder, CO, 80309.
authors.forename: Corey P
authors.initials: CP
authors.lastname: Neu
mesh_terms: D000328:Adult; D002358:Cartilage, Articular / Q000473:pathology*; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000473:pathology* / Q000503:physiopathology; D008279:Magnetic Resonance Imaging; D008297:Male; D055595:Mechanical Phenomena; D013314:Stress, Mechanical; D055815:Young Adult