Application of carbon-coated nanomultilayer sintered porous titanium microprosthesis for the repair of osteochondral defects of the knee joint

We constructed a carbon-coated nanomultilayer (CNM) sintered porous titanium (Ti) microprosthesis for the optimal treatment of osteochondral defects of the knee joint. Physicochemical property tests revealed that the porosity of the constructed porous Ti-CNM prosthesis was ∼75%, while the pore size ranged 300–400 μ m. The prosthesis had an elastic modulus (9.18 GPa) and compressive strength (98.3 MPa) similar to bone tissue. Furthermore, the CNM effectively reduced the roughness of the prosthesis surface. In animal experiments, the porous Ti-CNM improved the mineralization ability of osteoblasts in bone defects, as indicated by antialkaline phosphatase and osteocalcin, and improved bone mineral density, trabecular thickness, average trabecular number, and cortical bone thickness in the defective regions, thereby shortening the repair time. In addition, porous Ti-CNM effectively improved the production of extracellular matrix components in cartilage defects, such as collagen I, collagen II, and aggrecan, thereby enhancing the repair of cartilage defects and effectively preventing the degeneration of the opposite joint. The porous Ti-CNM prosthesis thus demonstrates great therapeutic potential for middle-aged patients with osteoarthritis.