Lower extremity scarring is often caused by trauma, burns, electric shock injuries and so on. If the early trauma is not treated properly, it often leads to scar healing, large scar or long strip scar, etc. The accompanying contracture can restrict the activity function of the lower limbs and cause scar contracture deformity, and in serious cases, it can also involve the lower abdomen and perineum, which seriously affects the daily life and makes the patient suffer great torture and pain mentally and physically, and forms extensive bone decalcification due to the long-term inability to move on the ground, which seriously affects the patient’s The physical health of the patient is seriously affected. The lower extremities are responsible for extremely important functional tasks such as weight bearing and walking. Due to the poor defense function of scar tissue, repeated abrasion, erosion and chronic ulceration often occur in the scar area, sometimes accompanied by repeated infections, even causing lymphangitis and elephantiasis, which can aggravate the scar and present a vicious cycle. In addition, the lower extremities are easily exposed body surface tissues, and sometimes scarring does not cause obvious lower extremity dysfunction, but it is obviously detrimental to local morphology and appearance. The purpose of lower extremity scar treatment can be divided into 3 aspects according to the essence: 1. to fully release the scar contracture, correct the deformity, and restore the local function by replacing the missing tissue amount through various methods such as local reshaping, flap transfer, and skin grafting; 2. to excise and reshape the scar without obvious functional impairment to improve the appearance and morphology; 3. to excise the scar tissue with chronic lesions to eliminate the hidden danger of malignant changes. In the treatment of large scars, surgeons who completely excise the scar will face the embarrassing situation of difficult to close the wound. The skin source is limited and the donor area is insufficient. At this time, functional repair should be the main focus, and large sheets of skin with good quality or free flaps should be placed in the joint activity area to ensure postoperative functional recovery as much as possible, and the remaining trauma can be repaired with mesh skin pieces, or the treatment can be divided into surgical sessions according to the situation. The widespread clinical application of skin soft tissue expansion techniques has brought more options and opportunities for the treatment of lower extremity scarring, and a better result can often be achieved by transferring the fully expanded skin soft tissue in stages. Postoperative functional exercise is extremely important for lower extremity scar treatment. Severe lower extremity scarring can be associated with joint stiffness and muscle atrophy, which cannot be completely restored by surgery alone. Surgical treatment creates conditions for limb function improvement, and postoperative functional exercises, such as physical therapy, physiotherapy, occupational therapy, and auxiliary measures such as elastic traction and braces, need to be persistently carried out in order to achieve maximum functional recovery. Treatment of N-fossa scar The N-fossa is located behind the knee joint and plays an important role in the anatomy and functional activities of the lower extremity, and its scar contracture deformity can seriously affect the function of the knee joint. Mild N-fossa scars can be treated with local reshaping surgery such as Z-plasty. If the N-fossa scar is large, a skin graft or flap transfer repair is required depending on the situation. When there is a lack of local flap donor area, free flap grafting is feasible. Commonly used flaps include scapular flap, anterolateral femoral flap, etc. Treatment of inguinal scarring Inguinal scarring is often caused by burns or electric shock injuries, and may be accompanied by contracture of the lower abdominal wall, marked displacement of the umbilicus, as well as perineal deformity and limited hip movement. Severe scarring of the inguinal region not only affects the function of the lower extremities, but also affects the function of the organs in the perineal region and the ability of the abdominal wall to gestate. Small areas of mild contracture of the scar can be treated by local reshaping surgery. Patients with large area of severe scar contracture need to have a rigorous surgical plan design before surgery and choose the appropriate surgery according to the specific situation. If the scar is superficial, it can be repaired by skin grafting after excision, if the scar is deeper and there are important blood vessels and nerves exposed after excision, it should be repaired by flap transfer or free flap grafting to ensure the functional recovery of the groin area, and skin expansion also has good results.