Fig. 4.

Representative SEM BSE images stitched together using MRICE to create an overhead cross-sectional view demonstrating HO and non-HO bone responses. Gray = bone and Black = soft tissue/pore space. (A) Sheep #7 showed HO-structured ectopic bone (EB) stemming from the posterior side along with osteonal remodeling (O) near the midcortex. Note the smooth periosteal response (PR) observed on the lateral side where the bone was roughened prior to the AID blast. A region of endosteal (E) remodeling was also observed within the canal adjacent to the drill hole on the lateral side. The anterior and medial regions showed no signs of significant bone response due to the AID blast as the native plexiform (PF) bone structure was still present. (B) Sheep #1 demonstrated similar results as Sheep #7. Image shows the HO ectopic bone (EB) and new bone growth stemming from the drill hole (DH) defect, which may have been influenced by the inoculated biofilm from the Si bead (Si). Endosteal (E) thickening appeared to be caused by biofilm resorbing the periosteum. Biofilms also appeared to form sequestrum bone (SB) on the lateral side. (C) Sheep #5—one out of the three sheep that did not contain the HO structure bone response. New bone growth is observed outside the normal boundary of the cortical bone on the posterior side at the linea aspera (LA) region along with a smooth periosteal response (PR) on the lateral side due to the bone roughening/periosteal disruption. (D) Sheep #3 demonstrated similar results as Sheep #5, with new bone (NB) growth at the linea aspera interface in addition to new bone growth filling in previously resorbed cortex due to the inoculated biofilm. Note the smooth periosteal response (PR) observed on the lateral side as well as the loose bone fragments (BF) around the Si beads (Si).