Abstract: A multifunctional composite drug coating sustained release system includes a transition layer and a drug-loaded degradable coating, wherein the transition layer is a ceramic transition layer having different porosities and the transition layer includes a dense lower layer and a porous upper layer. The multifunctional composite drug coating sustained release system is helpful to internal fixation and also has an antibacterial efficacy. A method for manufacturing the multifunctional composite drug coating sustained release system is also disclosed which includes: preparing a biocompatible ceramic transition layer on a metal surface; and then preparing a drug-loaded degradable coating on a surface of the biocompatible ceramic transition layer.

Abstract: A bone screw comprises a threaded portion. The threaded portion has a first thread including a first front surface (11), a first back surface (12) and a crest. A second thread including a second front surface (16) and a second back surface (17) is formed on at least part of the crest of the first thread. Because of the presence of the second thread, a contact area between the screw and a bone and an axial pullout force-bearing area are both significantly increased, without significantly influencing the bending resistance, so that the mechanical property of the screw is entirely improved.

Abstract: A bone screw comprises a threaded portion. The threaded portion has a first thread including a first front surface (11), a first back surface (12) and a crest. A second thread including a second front surface (16) and a second back surface (17) is formed on at least part of the crest of the first thread. Because of the presence of the second thread, a contact area between the screw and a bone and an axial pullout force-bearing area are both significantly increased, without significantly influencing the bending resistance, so that the mechanical property of the screw is entirely improved.