Abstract
In this pilot study, we investigated the biocompatibility and degradation rate of an extruded Zn–0.8Mg–0.2Sr (wt.%) alloy on a rabbit model. An alloy screw was implanted into one of the tibiae of New Zealand White rabbits. After 120 days, the animals were euthanized. Evaluation included clinical assessment, microCT, histological examination of implants, analyses of the adjacent bone, and assessment of zinc, magnesium, and strontium in vital organs (liver, kidneys, brain). The bone sections with the implanted screw were examined via scanning electron microscopy and energy dispersive spectroscopy (SEM-EDS). This method showed that the implant was covered by a thin layer of phosphate-based solid corrosion products with a thickness ranging between 4 and 5 µm. Only negligible changes of the implant volume and area were observed. The degradation was not connected with gas evolution. The screws were fibrointegrated, partially osseointegrated histologically. We observed no inflammatory reaction or bone resorption. Periosteal apposition and formation of new bone with a regular structure were frequently observed near the implant surface. The histological evaluation of the liver, kidneys, and brain showed no toxic changes. The levels of Zn, Mg, and Sr after 120 days in the liver, kidneys, and brain did not exceed the reference values for these elements. The alloy was safe, biocompatible, and well-tolerated.
Highlights
A Seronorm WB L-2 whole blood sample was used as a control
Zn–0.8Mg–0.2Sr alloy was successfully implanted into rabbits and monitored for 16 weeks (120 days), which presented a longer interval than in other published studies related to the application of zinc-based materials as bone implants
The screws were regularly dissolved at a corrosion rate of 0.014 mm/year without the production of any gas bubbles, which make this alloy superior to magnesium-based biodegradable materials
Summary
A vast improvement in living standards over the past few decades, has brought with it increasing demands to medicine. The classical concept for treatment of fractures utilizing steel or titanium plates and screws to stabilize a fractured bone brought with it the need for a secondary procedure to remove these metallic materials from the body. Experimentation began with the use of resorbable polymer materials. They are based on poly-lactic or poly-glycolic acids and their co-polymers. Units of polymers are broken down into water and carbon dioxide in the body.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
