3D-printed porous titanium changed femoral head repair growth patterns: osteogenesis and vascularisation in porous titanium.

Osteonecrosis of the femoral head (ONFH) is a major cause of morbidity, and total hip arthroplasty is both traumatic and expensive. Here, we created a gelatine scaffold embedded in uniquely shaped, 3D-printed porous titanium parts, which could attract and promote the proliferation of osteoblasts as well as bone regeneration, as the extracellular matrix (ECM) does in vivo. Interestingly, after hybridisation with platelets, the scaffold exhibited a low yet considerable rate of stable, safe and long-term growth factor release. Additionally, a novel ONFH model was constructed and verified. Scaffolds implanted in this model were found to accelerate bone repair. In conclusion, our scaffold successfully simulates the ECM and considerably accelerates bone regeneration, in which platelets play an indispensable role. We believe that platelets should be emphasised as carriers that may be employed to transport drugs, cytokines and other small molecules to target locations in vivo. In addition, this novel scaffold is a useful material for treating ONFH. An overview of the novel scaffold mimicking the extracellular environment in bone repair. a and b: A gelatine scaffold was cross-linked and freeze-dried within 3D-printed porous titanium. c: Platelets were coated onto the gelatine microscaffold after freeze-drying platelet-rich plasma. d: The microscaffold supported the migration of cells into the titanium pores and their subsequent growth, while the platelets slowly released cell factors, exerting bioactivity.