Reply to letter to the Editor regarding innovative 3D-printed porous TC4 prosthesis with nano-thin tantalum coating for treating complex wrist bone defects: A preliminary report of 3 cases

Reply

We are immensely grateful for the thoughtfully crafted Letter regarding our original article “Innovative 3D-printed porous TC4 prosthesis with nano-thin tantalum coating for treating complex wrist bone defects: A preliminary report of 3 cases,” and appreciated to have the opportunity to address those valuable questions. Before responding to the reviewer’s queries, please allow me to briefly summarize some of the key points we aimed to introduce in our article.

Concerning the limitations mentioned in the Letter, such as the relatively small sample size and the absence of a control group, we have already illuminated these in the discussion section of our original paper. Meanwhile, the primary purpose of this study was to systematically introduce, through the custom prosthetic reconstruction of three cases of complex wrist bone defects, the entire process and details of fabricating personalized bone defect prostheses by applying a tantalum (Ta) coating using Magnetron Sputtering (MSP) on a 3D-printed TC4 substrate.

The rationale behind preparing the Ta coating was to reduce the production costs of pure Ta prostheses, while simultaneously combining the advantages of TC4 and tantalum. Compared to other coating preparation techniques (such as CVD, thermal spraying, and electroplating), MSP not only enables the production of nano-scale tantalum coatings at room temperature but also results in coatings with superior purity, density, and adhesive strength. ¹ Additionally, magnetron sputtering is better suited for complex substrate surfaces and is more environmentally friendly. ²

In terms of production costs, MSP also offers a cost-effective advantage, making it feasible for regular hospitals to utilize this technology. It is important to note that MSP does not require hospitals to purchase specialized equipment. Given that MSP is a relatively mature technology, the preparation can be carried out by enterprises, with hospitals utilizing the final product. This embodies the essence of “medical-engineering interaction,” further reducing costs.

Regarding the issues raised in the Letter about the biosafety of Ta metal and Ta coatings, as well as the long-term prognosis of the prostheses, extensive basic and clinical research has already confirmed their high biocompatibility, excellent osseointegration capabilities, corrosion resistance, and wear resistance, demonstrating significant potential for long-term prognosis in the field of prosthetics. ³ They are particularly suitable for implants requiring rapid bone bonding and high stability. ⁴

In addition to wrist joint prostheses, we have also employed TC4-based Ta-coated prostheses for the reconstruction of complex acetabular and pelvic bone defects. These cases will be reported in the literature in the near future. We hope that the applications of these prostheses in various anatomical locations could provide substantial reference value to the community.

We believe that with the advancement of technologies like MSP, Ta coatings have the potential to become one of the mainstream choices for biomedical implant materials in the future. Meanwhile, considering the innovative nature of this technology and the lack of relevant clinical researches, it is indeed necessary to further accumulate long-term follow-up data from larger sample sizes and bone defects in various locations to verify safety and potential risks.