The classic grading method is the Wagner grading method. Grade 0: foot with high risk factors for ulcer development, currently free of ulcers. Grade 1: Ulceration of the skin surface of the foot, clinically free of infection. Grade 2: deeper ulcers, often combined with soft tissue inflammation, without abscesses or infection of the bone. Yu Xuchen, Department of Nephrology and Endocrinology, Dongzhimen Hospital, Beijing University of Traditional Chinese Medicine Grade 3: Deep ulcer, often affecting bone tissue, with deep abscess or osteomyelitis. Grade 4: Ischemic ulcer with localized or foot-specific areas of gangrene. Grade 5: Gangrene affecting the entire foot.