A versatile titanium–hydrogel platform bridging hard and soft tissue for joint arthroplasty

Hydrogel-based materials have been widely studied for their cartilage-like mechanical properties, but their clinical translation remains limited by the lack of a robust strategy to integrate tough hydrogels with bone-anchoring components while preserving structural integrity in anatomically relevant implant geometries. Here, we report a titanium–hydrogel platform addressing this challenge through a versatile interfacial design strategy. Tunable poly(vinyl alcohol)/polyacrylamide (PVA/PAAm) hydrogels were integrated with titanium components by combining silane surface modification with a triply periodic minimal surface (TPMS) architecture, yielding an interfacial bonding energy exceeding 1300 J m⁻². As examples, a hydrogel-based hip joint maintained low-friction articulation and structural integrity over 500,000 loading cycles (3000 N peak load, 12° rotation), while an artificial intervertebral disc reproduced asymmetric compression–tension behavior, symmetric torsional response, and dissipated over 80% of impact energy. Incorporation of antibiotics further enabled controlled drug release. This platform establishes a general strategy for integrating load-bearing hydrogels with rigid fixation components, enabling functional orthopedic implants with cartilage-like bearing surfaces.