Repair of Microdamage in Osteonal Cortical Bone Adjacent to Bone Screw

Abstract

Up to date, little is known about the repair mode of microdamage in osteonal cortical bone resulting from bone screw implantation. In this study, self-tapping titanium cortical bone screws were inserted into the tibial diaphyses of 24 adult male rabbits. The animals were sacrificed at 1 day, 2 weeks, 1 month and 2 months after surgery. Histomorphometric measurement and confocal microscopy were performed on basic fuchsin stained bone sections to examine the morphological characteristics of microdamage, bone resorption activity and spatial relationship between microdamage and bone resorption. Diffuse and linear cracks were coexisted in peri-screw bone. Intracortical bone resorption was significantly increased 2 weeks after screw installation and reach to the maximum at 1 month. There was no significant difference in bone resorption between 1-month and 2-months groups. Microdamage was significantly decreased within 1 month after surgery. Bone resorption was predisposed to occur in the region of <100 µm from the bone-screw interface, where had extensive diffuse damage mixed with linear cracks. Different patterns of resorption cavities appeared in peri-screw bone. These data suggest that 1) the complex microdamage composed of diffuse damage and linear cracks is a strong stimulator for initiating targeted bone remodeling; 2) bone resorption activities taking place on the surfaces of differently oriented Haversian and Volkmann canals work in a team for the repair of extensive microdamage; 3) targeted bone remodeling is a short-term reaction to microdamage and thereby it may not be able to remove all microdamage resulting from bone screw insertion.

Positive effect of strontium‐oxide layer on the osseointegration of moderately rough titanium surface in non‐osteoporotic rabbits

“…Wang et al. () confirmed that the activity of bone resorption in peri‐screw bone only increased within 1 month after surgery. The cancellous bone around the implants that are absent of loading may have gone through the disuse bone resorption at 6 weeks after implantation.…”

Bone remodeling and mechanobiology around implants: Insights from small animal imaging

“…Elevated resorption rates have been observed in the implanted caudal vertebrae, with the tendency to be less localized around the implant and being sustained for a longer time interval than formation rates . A possible explanation for high bone resorption is the need to remove microdamage produced by implantation …”

Self‐healing materials: what can nature teach us?

“…The capacity to repair local damage also allows the material to respond efficiently to stress concentrations. For example, regions of bone close to a metal screw inserted as part of an orthopaedic operation develop increased numbers of microcracks, which are subsequently remodelled …”