Periosteal Distraction With Skin Grafting for DFU

Inclusion Criteria: * Age ≥18 years on the day of signing informed consent. * Diagnosed with type 2 diabetes mellitus. * Diabetic foot ulcer persisting for ≥2 weeks. * Wagner grade 2 or 3; or post-amputation (Wagner grade 4-5) wound requiring skin grafting. * Wound area ≥3 cm². * Brachial-ankle index between 0.71 and 1.30. * Hemodynamically stable with routine examinations indicating tolerance to surgery. * Mentally competent, able to follow medical advice, and willing to attend scheduled follow-up visits. * Understand and voluntarily sign informed consent to participate in this trial. Exclusion Criteria: * Poorly controlled hyperglycemia (e.g., HbA1c \>12.0%). * Immunosuppression due to underlying disease, long-term immunosuppressive therapy, or high-dose glucocorticoids (e.g., ≥40 mg prednisone or equivalent daily for ≥2 weeks) during screening. * Preexisting conditions affecting wound healing (e.g., malignancy, autoimmune disease). * Severe uncontrolled systemic disease or acute systemic infection; concomitant severe cardiac, pulmonary, or cerebral disease. * Psychiatric disorders. * Deemed unsuitable for inclusion by the investigator. * Pregnancy, unwillingness to use adequate contraception in women of childbearing potential, lactation, or planning pregnancy within 1 month after study completion. * Active osteomyelitis in the target ulcer without adequate debridement and/or antibiotic treatment. * Significant uncorrected biomechanical deformity expected to severely affect graft survival and function. * Active bleeding or significant coagulation abnormality. * Previous participation in this study at any time.