Titanium Porous Coating Using 3D Direct Energy Deposition (DED) Printing for Cementless TKA Implants: Does It Induce Chronic Inflammation?

Abstract

Because of the recent technological advances, the cementless total knee arthroplasty (TKA) implant showed satisfactory implant survival rate. Newly developed 3D printing direct energy deposition (DED) has superior resistance to abrasion as compared to traditional methods. However, there is still concern about the mechanical stability and the risk of osteolysis by the titanium (Ti) nanoparticles. Therefore, in this work, we investigated whether DED Ti-coated cobalt-chrome (CoCr) alloys induce chronic inflammation reactions through in vitro and in vivo models. We studied three types of implant surfaces (smooth, sand-blasted, and DED Ti-coated) to compare their inflammatory reaction. We conducted the in vitro effect of specimens using the cell counting kit-8 (CCK-8) assay and an inflammatory cytokine assay. Subsequently, in vivo analysis of the immune profiling, cytokine assay, and histomorphometric evaluation using C57BL/6 mice were performed. There were no significant differences in the CCK-8 assay, the cytokine assay, and the immune profiling assay. Moreover, there were no difference for semi-quantitative histomorphometry analysis at 4 and 8 weeks among the sham, smooth, and DED Ti-coated samples. These results suggest that DED Ti-coated printing technique do not induce chronic inflammation both in vitro and in vivo. It has biocompatibility for being used as a surface coating of TKA implant.

3D printing metal implants in orthopedic surgery: Methods, applications and future prospects

“…Many universities and institutions have independently studied LDMD, leading to various names for the technology, such as laser engineered net shaping (LENS), directed energy depositioin (DED), laser rapid forming (LRF), etc. Similar to SLS, the laser system is also the heating element, but the difference is that the LDMD heats and melts the metal substrate [ 40 ]. Due to the large laser focused spot, the printing accuracy is generally above 1 ​mm.…”

Enhanced osseointegration through direct energy deposition porous coating for cementless orthopedic implant fixation

“…For reliable in vitro and in vitro studies, we determined the minimum sample size using G*Power 3.1 software (Heinrich-Heine University, Dusseldorf, Germany), based on similar studies that we have performed previously 41 – 43 . The minimum sample size for each in vitro study was calculated (α = 0.05, β = 0.2) based on the mean and standard deviation of the OD values of the CCK-8 assay, and the minimum sample size for each in vivo study was determined based on the mean and standard deviation of BIC.…”

Osteo-Compatibility of 3D Titanium Porous Coating Applied by Direct Energy Deposition (DED) for a Cementless Total Knee Arthroplasty Implant: In Vitro and In Vivo Study

“…To set the baseline, a positive control, a cell-only group was included in the in vitro experiments. For in vitro study, on the basis of the data obtained from our previous study [20], a sample size calculation (α = 0.05, β = 0.2) was conducted in terms of the mean and standard deviation of optical density (OD) value of CCK-8 assay using G power 3.1 [21]. Six specimens in each in vitro study are needed as the minimum requirement to ensure 80% power.…”