Figure 7: Organization and composition of human osteonecrosis subchondral bone has hallmarks of defective perilacunar remodeling.

Trabeculae from the sclerotic regions of human osteonecrotic femoral heads (B,E,H,K,N) show histologic and radiographic hallmarks of defective perilacunar remodeling relative to trabeculae that are distant from the lesion (A,D,G,J,M). These include reduced MMP-13 expression as assessed by immunohistochemistry for MMP-13 or negative control (A–C) (scale bar = 20 μm), defects in collagen organization as assessed using picrosirius red staining (D–F) (scale bar = 50 μm), and reduced canalicular length as assessed by silver nitrate staining (G–I). For graph, bars represent mean ± SEM of n ≥ 3 regions from either normal human cadaveric or human osteonecrotic bone samples, *p-value ≤ 0.05 compared to control. As in GC-treated mouse bone, SRμT shows hypermineralization (L) (red arrows highlight hypermineralized, sclerotic, collagen layers) and reduced lacunar size (O) in the bone from human osteonecrosis lesions (K,N) relative to trabeculae that are more distant (J,M). Vertical dotted lines signify peak lacunar volume values.