title: Systematic mapping of the subchondral bone 3D microarchitecture in the human tibial plateau: Variations with joint alignment.
abstract: Tibial subchondral bone plays an important role in knee osteoarthritis (OA). Microarchitectural characterization of subchondral bone plate (SBP), underlying subchondral trabecular bone (STB) and relationships between these compartments, however, is limited. The aim of this study was to characterize the spatial distribution of SBP thickness, SBP porosity and STB microarchitecture, and relationships among them, in OA tibiae of varying joint alignment. Twenty-five tibial plateaus from end-stage knee-OA patients, with varus (n = 17) or non-varus (n = 8) alignment were micro-CT scanned (17 μm/voxel). SBP and STB microarchitecture was quantified via a systematic mapping in 22 volumes of interest per knee (11 medial, 11 lateral). Significant within-condylar and between-condylar (medial vs. lateral) differences (p < 0.05) were found. In varus, STB bone volume fraction (BV/TV) was consistently high throughout the medial condyle, whereas in non-varus, medially, it was more heterogeneously distributed. Regions of high SBP thickness were co-located with regions of high STB BV/TV underneath. In varus, BV/TV was significantly higher medially than laterally, however, not so in non-varus. Moreover, region-specific significant associations between the SBP thickness and SBP porosity and the underlying STB microarchitecture were detected, which in general were not captured when considering the values averaged for each condyle. As subchondral bone changes reflect responses to local mechanical and biochemical factors within the joint, our results suggest that joint alignment influences both the medial-to-lateral and the within-condyle distribution of force across the tibia, generating corresponding local bony responses (adaptation) of both the subchondral bone plate and underlying subchondral trabecular bone microarchitecture. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1927-1941, 2017.
authors.affiliation: The Medical Device Research Institute, School of Computer Science, Engineering and Mathematics, Flinders University, GPO Box 2100, Adelaide, South Australia 5001, Australia.
authors.forename: Bryant C
authors.initials: BC
authors.lastname: Roberts
authors.affiliation: Alliance for Research in Exercise, Nutrition and Activity, Sansom Institute for Health Research, University of South Australia, Adelaide, South Australia, Australia.|Centre for Orthopaedic and Trauma Research, The University of Adelaide, Adelaide, South Australia, Australia.
authors.forename: Dominic
authors.initials: D
authors.lastname: Thewlis
authors.affiliation: Centre for Orthopaedic and Trauma Research, The University of Adelaide, Adelaide, South Australia, Australia.|Department of Orthopaedics and Trauma, Royal Adelaide Hospital, Adelaide, South Australia, Australia.
authors.forename: Lucian B
authors.initials: LB
authors.lastname: Solomon
authors.affiliation: Department of Orthopaedic Surgery, Repatriation General Hospital, Daws Park, South Australia, Australia.
authors.forename: Graham
authors.initials: G
authors.lastname: Mercer
authors.affiliation: The Medical Device Research Institute, School of Computer Science, Engineering and Mathematics, Flinders University, GPO Box 2100, Adelaide, South Australia 5001, Australia.
authors.forename: Karen J
authors.initials: KJ
authors.lastname: Reynolds
authors.affiliation: The Medical Device Research Institute, School of Computer Science, Engineering and Mathematics, Flinders University, GPO Box 2100, Adelaide, South Australia 5001, Australia.
authors.forename: Egon
authors.initials: E
authors.lastname: Perilli
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000473:pathology; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging* / Q000473:pathology; D016062:Porosity; D013977:Tibia / Q000000981:diagnostic imaging*; D055114:X-Ray Microtomography
keywords: bone microarchitecture; knee osteoarthritis; micro-CT; regional variations; subchondral bone