**5. Conclusions**

The e ffect of CaP ECD deposition on the MSC-Sca ffold prototype is conditioned not only by the appropriate choice of electric parameter values of the ECD process but also on the geometrical features (distance between the spikes) of the MSC-Sca ffold. Of the two examined design variants, the distance between spike bases of 200 μm (PSc200) and 350 μm (PSc350), the PSc200 MSC-Sca ffold variant appeared to be inappropriate to be CaP modified in the ECDV=const process.

Based on the SEM and EDS studies of deposited CaP coatings together with the measurements of the weight increase for the PSc350MSC-Sca ffold pre-prototypes, the most suitable VECD values for the ECDV=constprocess were from −5.25 to −4.75 V and the best results for CaP modification of their bone-contacting surfaces was obtained at VECD = −5.00 V; the native biomineral Ca/P ratio of coatings was achieved for all the VECD values used.

ECD combined with AAT pretreatment prevents micro-crack formation on the bone-contacting surfaces of the MSC-Sca ffold prototype and increases the spikes' lateral surface coverage; the best results for the CaP modification of the bone-contacting surfaces was obtained at VECD = −5.00 V.

Thus, the biomimetic MSC-Sca ffold prototype with desired biomineral coating of native Ca/P ratio on bone-contacting surfaces was obtained for a new kind of entirely non-cemented resurfacing arthroplasty endoprostheses.

**Author Contributions:** Conceptualization, R.U. and M.W.; Funding acquisition, R.U.; Investigation, R.U., M.W., P.K. and R.T.; Methodology, R.U., M.W., P.K. and R.T.; Project administration, R.U.; Supervision, R.U.; Visualization, M.W.; Writing—original draft, M.W.; Writing—review & editing, R.U. and M.W.

**Funding:** This work was supported by Polish National Science Centre [NN518412638].

**Acknowledgments:** This research was supported by the Polish National Science Centre by Research Project no. NN518412638: "The thermochemical surface modification of preprototypes of the minimally invasive RHA endoprostheses and porous intraosseous implants." Head: Ryszard Uklejewski.

**Conflicts of Interest:** The authors declare that there are no conflicts of interest regarding the publication of this paper.
