Corrosion of magnesium alloy AZ31 screws is dependent on the implantation site

Building towards a standardised approach to biocorrosion studies: a review of factors influencing Mg corrosion in vitro pertinent to in vivo corrosion

“…There was also some degree of tissue encapsulation on the head of the screws, which was in contact with the cranial tibial muscle. A similar result was observed by Willbold et al [122] following implantation of AZ31 screws into the hip bone of mature female sheep. Myrissa et al [132] implanted Mg pins transcortically into the femoral bone of male Sprague-Dawley rats.…”

“…For orthopaedic applications small animal studies are generally conducted in rodents such as rats or rabbits [18,27,120,121]. For larger animal studies sheep [122] and pigs [123] have been used previously, with dogs and goats also established in the field [119]. In cardiovascular applications rats are also used as a small animal model [124][125][126], with pigs generally favoured once large animal trials are required [127].…”

In vitro and in vivo studies on the degradation of high-purity Mg (99.99wt.%) screw with femoral intracondylar fractured rabbit model

“…In previous study, numerous studies have been focusing on the degradation performance of Mg-based screws inserted to intact host bone, i.e. AZ31 screw in rabbit mandible [29] and sheep hip bone [30], MgCa0.8 alloy screws in rabbit tibiae [31], which performed a in vivo stale and gradual corrosion rate. Furthermore, Gu et.al [12] and Kannan et.al [32] revealed corrosion promotion of Mg-based materials (as cast AZ91D, as extruded As the corrosion proceeds, the degeneration of mechanical integrity was expected.…”

“…Histological examination also showed matured bone tissue ingrowth in HP Mg screw. Much evidence proved good osseointegration and bone ingrowth around Mg alloy screws[29,30,38]. Therefore, it was supposed Mg ion, which evolved during thedegradation of the Mg material, significantly affected the osteogenic differentiation of the surrounding tissue.…”

In vitro degradation behavior and cytocompatibility of biodegradable AZ31 alloy with PEO/HT composite coating

“…However, under complex conditions in vivo, the composite coating may perform differently in lifespan compared with in vitro tests results. As the corrosion rate of magnesium-based implants are related to the implantation site [42], an adjustable corrosion rate of the implant based on applications is required. As discussed above, the corrosion resistance of PEO coating and HA layer can both be controlled by adjusting their thickness and structures, thus, the PEO/HT coating is promising as anticorrosive layer with adjustable lifespan to balance the degradation rate to meet the speed of the tissue reconstruction during in vivo implantation.…”