Abstract
Osteoarthrosis (OA) stands alongside cancer and heart disease as one of the major causes of suffering and disability amongst the elderly. Changes related to OA occur in all elements of the joint, and there are indications that sub-chondral cancellous bone plays a primary role in the cartilage degeneration in OA. Most previous investigations have been focused on moderate and late OA, whereas little is known about the changes in cancellous bone microstructure in human early OA. This study quantified cancellous bone microstructure in early-stage OA using three-dimensional (3D) methods.
Subchondral cancellous bone specimens, produced from 10 human post-mortem early-stage osteoarthrotic (OA) proximal tibiae and 10 normal age- and gender-matched proximal tibiae, were allocated to 4 groups: medial OA, lateral control, normal medial control, and normal lateral control. OA initiates mostly at the medial condyle, and histological analysis was done to confirm this change. The cylindrical specimens were micro-computed tomography (micro-CT) scanned. From accurate 3D data sets, structural parameters were determined by means of true, unbiased and assumption-free 3D methods. The data were assessed statistically, and a p< 0.05 was considered significant.
Our data supported the hypothesis that significant microstructural changes – other than density changes – occur in early-stage OA cancellous bone. OA cancellous bone is markedly plate-like, less anisotropic, less interconnected, but lower in mechanical properties which suggests a disorganisation in the microstructure as OA initiation. Structure model type best explains the mechanical properties for the OA and the normal controls. However, the determination coefficients (R2) for the OA group are largely reduced. These results indicate significant property and quality deterioration in early-stage OA subchondral cancellous bone.
