Fig. 2

At 24 weeks after implantation of polyvinyl alcohol/nano-hydroxyapatite and polyamide 66. No obvious changes were observed in the peripheral articular cartilage; the contralateral articular surface was smooth (a). At 24 weeks after implantation of polyvinyl alcohol, the implant had dropped and was not firmly fastened into the joint (b). At 24 weeks in the control group, the surface of joint appears rough and articular cartilage in the surrounding region presented with degenerative changes (c)