Adaptive smart hydrogels driving precision bone healing in pathological contexts.

Pathological bone defects remain formidable clinical challenges due to their dynamically hostile microenvironments, typified by chronic inflammation, acidosis, hypoxia, and oxidative stress. Conventional therapeutic strategies, dependent on static scaffolding and passive drug release, often fail to meet the demand for precise and adaptive intervention. Emerging adaptive smart hydrogels, endowed with dynamic regulatory capabilities, are reshaping the paradigm of bone repair by enabling spatiotemporally controlled drug delivery, degradation, immunomodulation, and cellular regulation. Harnessing both physical triggers (light, temperature, electricity, magnetism, ultrasound) and chemical/biological cues (pH, redox, enzymatic activity), these hydrogels provide real-time responsiveness and targeted therapeutic action. This review discusses the pathological contexts of bone defects and systematically elaborates on the dynamic regulatory mechanisms of adaptive hydrogels while highlighting their innovative applications in diabetic bone defects, bone tumors, osteoporosis, osteoarthritis, and periodontitis. We further emphasize their roles in precision immunomodulation, osteogenesis, and tumor inhibition. Finally, we outline key challenges and propose future directions, including personalized design strategies, multimodal integration, and convergence with bioelectronics and AI-assisted material design, to accelerate clinical translation. This work aims to inspire interdisciplinary innovation and guide the development of intelligent hydrogel-based strategies for precision bone healing in complex pathological contexts.