Cohort of Lower-Extremity Sports Injuries and Degeneration(Yongjiang Cohort)

This is an observational cohort study conducted at Ningbo No. 2 Hospital. The study will include patients with knee-related sports injuries or degenerative knee conditions who receive routine clinical care. The purpose is to build a standardized real-world clinical cohort and evaluate knee injury, degeneration, recovery, and long-term outcomes. After informed consent, participants will undergo baseline data collection, including medical history, laboratory tests, questionnaires, X-ray and MRI imaging, and functional assessments. Patients younger than 50 years will mainly be assessed for sports injury and functional recovery, while patients aged 50 years or older will receive additional sarcopenia-related assessments such as grip strength, DXA testing, and gait evaluation. No experimental treatment, randomization, or intervention will be assigned. Participants will be followed at about 6, 12, and 24 months after treatment or surgery to assess knee function, imaging changes, reinjury, reoperation, pain, quality of life, falls, and functional decline. The study plans to enroll about 500 participants.