While standard orthopaedic prostheses are often a viable option, they are not always feasible for cancer patients; on the other hand, the extended lead times for acquiring custom-made commercial implants present significant challenges. We aimed to assess the osseointegration of in-house custom 3D-printed titanium implants through a randomised animal study. Its purpose was to evaluate whether there is a statistically significant difference between in-house porous, rough-surface and solid, smooth-surface scaffold design regarding mechanical and histological osseointegration. Twenty stable, non-weight-bearing cylindrical implants (6×10 mm) were 3D printed, with 10 having a rough surface and ten a smooth surface. Implants were randomised into the left humerus of 20 skeletally mature sheep. After four weeks, all sheep were euthanised. Each specimen was then cut into a block for mechanical test, closest to the surgical entry site, and another for histomorphometric evaluation. Data were evaluated using Mann-Whitney U test. Solid implants demonstrated a complete absence of osseointegration as they detached from the bone during sample preparation, unlike porous implants, which showed macroscopic integration and a breaking point at implant´s surface. A statistical comparison with mechanical testing was, therefore, deemed not necessary. Histomorphometry showed a statistically significant difference in the amount of foreign-body membrane (p=0.037) and fibrous tissue (p=0.049) between the two groups in the gap and between all tissues on the surface (bone: p=0.006; foreign-body membrane: p=0.0001; fibrous tissue: p=0.0001). In conclusion, our study shows superior osseointegration of in-house 3D-printed implants with a porous surface. Future research should focus on weight-bearing implants.
Borgognoni et al. (Wed,) studied this question.