Commercial decalcified bone scaffolds were combined with autologous bone marrow mesenchymal stem cells to form tissue engineered bone in vitro to explore the effect of this tissue engineered bone in the clinical repair of long tubular bone defects in limbs.

Bone defects caused by trauma, tumors, and other factors, particularly weight-bearing long tubular bone defects in the limbs, pose significant harm to patients and severely impact their quality of life, remaining a major clinical challenge. Current repair methods such as autologous bone grafting, vascularized autologous bone grafting, allogeneic bone grafting, induced membrane technique, and bone transport technique face limitations including lengthy treatment cycles, high costs, restricted donor sites and bone harvest quantities, and unpredictable outcomes.

To address these challenges, the National Engineering Research Center for Tissue Engineering has developed an innovative approach through continuous research and innovation. This method utilizes autologous bone marrow mesenchymal stem cells (BMSCs) with minimal invasiveness, strong proliferation capacity, and potent osteogenic potential as seed cells for bone construction. These cells are combined with clinically approved allogeneic decalcified bone materials to create tissue-engineered bone through in vitro induction. This approach offers multiple advantages: absence of immune rejection, unrestricted material sources, sufficient cultured bone volume, and high survival rates, providing a new direction for treating long tubular bone defects in limbs.

This study aims to evaluate the clinical efficacy of tissue-engineered bone constructed with autologous BMSCs for repairing long bone defects in extremities, thereby providing evidence-based support for bone defect treatment.

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.