[Emphasizing the damage and repair of bone collagen in osteoporosis]

Osteoporosis is characterized not only by reduced bone mass but also by impaired structure and function of the bone matrix and bone collagen. Although conventional bone mineral density assessment can reflect the level of bone mineralization, it cannot fully capture bone quality and the biomechanical performance of bone tissue. Bone collagen plays a critical role in maintaining bone tissue toughness, energy-absorbing capacity and the stability of bone microarchitecture. Its abnormal cross-linking, degradation and defective repair are closely associated with increased bone fragility. This article focuses on the roles and values of bone collagen in osteoporosis, elaborates on bone collagen-related pathological changes, influencing factors, and its mechanisms in osteoporotic fractures, and introduces the latest diagnostic and therapeutic technologies as well as future development directions. It highlights the great value of establishing a "mineralized-collagen two-dimensional" bone-quality evaluation system that takes both bone mineralization and bone collagen status into account, providing new insights for the precise diagnosis and treatment of osteoporosis and osteoporotic fractures.