Bone Reconstruction With Autologous Bone Marrow Mesenchymal Stem Cells in Vitro to Repair Long Tubular Bone Defects

Inclusion Criteria: 1. Age: 18-55 years old, gender unrestricted; 2. Defective nonunion with bone loss exceeding 30% of the bone cross-section and a length of 2-3 cm; 3. Solitary bone cysts involving more than 50% of the bone cross-section. Exclusion Criteria: 1. Combined with local tumors, tuberculosis, infections or other bone-healing affecting lesions; 2. Systemic diseases affecting bone healing such as osteofibrous dysplasia, osteogenesis imperfecta, bone dystrophic diseases, and metabolic bone disorders; 3. Moderate-to-severe osteoporosis (BMD: T-score \< -2.5); 4. Severe systemic conditions including systemic malnutrition, systemic infectious diseases, severe cardiopulmonary diseases, coagulation disorders, and major organ failure; 5. Complicated with severe brain trauma; 6. Heavy smoking, drug abuse, alcoholism, or other harmful addictions; 7. Psychiatric disorders or patients with menopausal symptoms; 8. Concurrent participation in other studies or recent completion (within 4 weeks) of other clinical trials; 9. Pregnancy, lactation, or planned pregnancy within one year after initial enrollment; 10. Psychological conditions impairing treatment compliance; 11. Congenital malformations of vital organs or other systems; 12. Nonunion caused by malignant tumor resection; 13. Refusal to accept tissue-engineered bone repair protocol.