Inclusion criteria:  Outpatients, inpatients, follow-up patients and third-class blood relatives or close relatives of patients with degenerative osteoarthritis who were admitted to the Institute of Sports Medicine of the Third Hospital of Peking University voluntarily enrolled in the biobase. Outpatients, inpatients, follow-up patients and third-class blood relatives or close relatives of patients with cruciate ligament injury who were admitted to the Institute of Sports Medicine of the Third Hospital of Peking University voluntarily enrolled in the biobase. Outpatients, inpatients, follow-up patients and third-class blood relatives or close relatives of patients with patella dislocation who were admitted to the Institute of Sports Medicine of the Third Hospital of Peking University voluntarily enrolled in the biobase. Outpatients, inpatients, follow-up patients and third-class blood relatives or close relatives of patients with discoid meniscus who were admitted to the Institute of Sports Medicine of the Third Hospital of Peking University voluntarily enrolled in the biobase.  Exclusion criteria: -.