Early osseointegration of two in-house 3D-printed porous titanium implant designs: an in vivo sheep study.

INTRODUCTION

Early osseointegration is critical for long-term implant stability, and in-house 3D-printed porous surfaces may enhance bone integration by promoting cellular migration and tissue formation, provided that porosity is balanced with sufficient mechanical strength. This randomized animal study assessed whether statistically significant differences exist between custom 3D-printed titanium implants with a pore size of 630 μm and porosity of 73.9% (P1) and implants with a pore size of 690 μm and porosity of 69.1% (P2) regarding mechanical and histological osseointegration.

METHODS

Twenty stable, non-weight- bearing cylindrical implants (6 × 10 mm), comprising ten P1 and ten P2 implants, were randomly inserted into the medial left femoral condyle of 20 skeletally mature sheep. After 4 weeks, the animals were euthanized, and each specimen was divided into one block for mechanical axial push-out testing and another for histomorphometric evaluation.

RESULTS

Statistical analysis using the Mann-Whitney U test demonstrated no significant differences between P1 and P2 in strength (MPa; p = .87), energy (J/m2; p = .80), or stiffness (MPa/mm; p = .66). Histomorphometric analysis likewise revealed no significant differences in bone or fibrous tissue fractions between groups, and no foreign body reaction was observed in any specimen.

DISCUSSION: Within the limitations of this study, no statistically significant differences were detected between the two porous implant designs with respect to early osseointegration, and future research should investigate their performance in weight-bearing conditions.