Smart hydrogel-based anticancer strategies for postoperative osteosarcoma management
Postoperative osteosarcoma (OS) treatment remains challenging due to local recurrence, pulmonary metastasis, chemoresistance, and critical-sized bone defects that cannot self-repair. Although hydrogel-based biomaterials have emerged as promising localized therapeutic platforms, existing reviews primarily focus on individual hydrogel types or therapeutic strategies without critically evaluating their translational potential. Here, we comprehensively summarize recent advances in drug-eluting, ion-releasing, micro/nanogel, composite, surface-functionalized, and cell-laden hydrogels for postoperative OS management. Particular emphasis is placed on biomaterial design, controlled therapeutic delivery, bone regeneration, and emerging biofabrication approaches, including 3D/4D bioprinting and biomimetic constructs. More importantly, this review critically compares the therapeutic mechanisms, regenerative performance, and translational readiness of these hydrogel systems, highlighting key challenges related to mechanical performance, degradation control, metastasis management, manufacturing scalability, and long-term clinical feasibility. Finally, we discuss future design strategies required to develop clinically translatable multifunctional hydrogel platforms for postoperative osteosarcoma treatment.