Objective To investigate the preparation of composite cartilage supported grafts made by injectable platelet rich fibrin (i-PRF) mixed with cartilage particles covering on high-density porous polyethylene (HPDE).

Methods Cartilage particles and i-PRF were obtained and HPDE materials were prepared. Composite supporting grafts were prepared and were divided into group A (pure HPDE material group), group B (i-PRF+HPDE material group), group C (cartilage particles +HPDE material group) and group D (i-PRF+ cartilage particles +HPDE material group). The grafts were buried subcutaneously in the back of 9 New Zealand white rabbits (each white rabbit was implanted one graft on the upper, lower, left and right sides of the back), and the in vivo experiments and histological observation of the grafts were conducted.

Results Visual observation results showed that group D had less cartilage particles lost, and the surface fibrous vessels were more abundant compared with the group C at 12 weeks after surgery. The results of hematoxylin and eosin(HE)staining and saffron O-solid green staining showed that the composite cartilage supported graft containing i-PRF in the group D could form cartilage particles sooner than group C. Immunohistochemical results showed the group D whose cartilage grafts contained i-PRF had faster type Ⅱ collagen connection than group C. Masson staining results showed that collagen fibers in the pore diameter of HPDE material containing i-PRF in group B were more dense than group A. Immunofluorescence results showed that neovasculation in its aperture of HPDE material containing i-PRF in group B was more dense than group A.

Conclusion The cartilage particles of composite cartilage particles formed by i-PRF mixed with cartilage particles in support graft are faster in connecting into pieces, and the cartilage particles are better fixed in place. Compared with the simple implantation of HPDE material, the collagen and fiber vascular grow more into porosity of HPDE material containing i-PRF, which is suitable for clinical requirements in application.