Superior In Vitro Osteo-Supportive Properties of Trabecular Titanium vs. Chromium–Cobalt Scaffolds

Background: Degenerative joint diseases are a major cause of disability and drive the increasing demand for joint arthroplasty. Long-term prosthesis success depends on rapid and stable bone–implant integration, which is influenced by the osteo-inductive and osteo-conductive properties of implant materials. Chromium–cobalt (CrCo) and titanium (Ti) alloys are widely used in reconstructive orthopedics, but direct comparative data on their biological performance, particularly for trabecular titanium (T-Ti), remain limited. This study aimed to directly compare the biocompatibility and osteogenic potential of CrCo and T-Ti using human mesenchymal stromal cells (MSCs). Methods: Human MSCs were characterized by immunophenotyping and cultured on CrCo and T-Ti scaffolds under control and osteogenic conditions for up to 28 days. Cell adhesion and morphology were assessed by scanning electron microscopy. Proliferation and viability were quantified, and osteogenic differentiation was evaluated using alkaline phosphatase activity, calcium deposition assays, and gene expression profiling of osteogenic markers. Results: Both materials supported MSC adhesion and proliferation, confirming cytocompatibility. Under control conditions, T-Ti significantly increased alkaline phosphatase activity and osteogenic gene expression. Under osteogenic stimulation, T-Ti accelerated differentiation and mineralized matrix deposition. CrCo exhibited limited stimulation of the osteogenic-supportive microenvironment and delayed differentiation responses. Conclusions: Trabecular titanium, in terms of morphology and topology, provides a biologically active scaffold that both induces and conducts osteogenic differentiation of human MSCs, whereas CrCo acts primarily as a mechanically optimized but biologically passive material. These findings support the use of trabecular titanium at bone-contact interfaces in joint prostheses to enhance osteointegration and potentially improve long-term implant stability.