Figure 5.

(A) The Mg screw coated with a thin layer of polymer coating film on the screw head (transparent part); (B) the plate with coated Mg screw (purple one) and Ti screws; (C) hypothesised working mechanisms of the proposed innovative Mg-containing hybrid fixation system for fracture fixation at long bone fracture. The fracture was fixed by Ti plate (pointed by dark blue arrow) and six Ti screws (demonstrated with dark grey). The purple screw next to the fracture gap is Mg screw. The positions and number of the Mg screws can be justified according to the fracture types. After fixation, the Mg screw degrades gradually (pointed by purple arrows) and larger fracture callus (pointed by green arrows) is induced to promote fracture healing, based on previous published articles [16], [111]. When the fracture heals, the Mg screw is fully absorbed and no screw hole is remained (pointed by purple arrow in the last figure). With less fixation screws remained, the fixation system can be easily removed and the healing efficiency and quality can be both enhanced by the degradation of Mg screws.