Objective To summarize the clinical experience of using several different types of tipped flaps to repair deep wounds in patients with severe lower extremity burns. Methods More than 20 types of axial vascular-tip island flaps, myocutaneous flaps, and local fascial flaps were used to repair 271 deep wounds in 236 patients with burn wounds of the lower extremities. Results 271 wounds were repaired with 332 tipped flaps, among which 28 wounds required combined flap grafting; one flap was completely necrotic, three were partially necrotic, and the rest were completely viable and all wounds were healed. Conclusion The tipped flap can meet the need of covering deep wounds of lower extremity burns, and the appropriate flap can be selected according to the degree of local tissue damage caused by burns, and the complex wounds can be repaired by combined transplantation of multiple flaps when necessary. Severe traumatic burns often lead to serious damage to deep tissues of patients, and the limb is a good site for burn trauma. Selecting appropriate flaps to cover the trauma in time, stopping the progressive necrosis of inter-ecological tissues, filling the dead cavity, and protecting important structures such as neurovascular tendons are the keys to deal with complex burn trauma wounds. However, there are relatively few tissues for mobilization in the lower extremities, and wound repair is more difficult. Most scholars have long used free flaps as the first choice for repairing distal calf and foot depth trauma. Since 1998, we have used a variety of tipped flaps to repair 271 lower extremity wounds in 236 burn trauma patients, 28 of which were combined with more than 2 flaps, as reported below. Data and methods 1. Clinical data: In this group of burn trauma patients, there were 192 males and 44 females, aged 4 to 73 years. Causes of trauma formation: 116 cases of burns (48 cases of electric burns, 30 cases of thermal pressure injuries such as red steel locomotives, 22 cases of hot water bags, 16 cases of exhaust pipes), 86 cases of trauma, 18 cases of chronic osteomyelitis, 9 cases of body surface or bone tumors, and 7 cases of others. The total burn area was (2.98±3.04)% TBSA, including Ⅲ degree (2.32±2.49)% TBSA. 271 trauma distribution: calf 164, foot 45, knee 25, hip 21, thigh 16. important tissue exposure: 114 cases of bone exposure, 79 cases of tendon exposure, 36 cases of important trunk vessel exposure, 17 cases of nerve exposure, 8 cases of joint cavity exposure Some of these cases combined with the exposure of multiple important tissues. 2. Methods: (1) Types of flap transplantation: 332 flaps were formed, including 59 gastrocnemius muscle flaps (51 medial head, 5 lateral head, 3 medial-lateral head), 24 gastrocnemius nerve trophic flaps, 23 saphenous artery flaps, 21 medial superior ankle fasciocutaneous flaps, 13 broad fascial tensor fasciae muscle flaps, 11 flounder muscle flaps, 10 lateral superior ankle fasciocutaneous flaps, 9 sutures muscle flaps 9, [9 adductor muscle flaps, 8 posterior calf flaps, 7 insular dorsalis pedis flaps, 6 anterolateral femoral flaps, 5 medial foot flaps, 4 peroneus longus muscle flaps, 4 anterior tibialis muscle flaps, 21 other muscle flaps or flaps, and 48 other fascial flaps. (2) Combined application of flaps: 243 of 271 wounds were repaired with 1 flap, and the remaining 28 wounds were repaired with 2 or more flaps, 10 of which were repaired with 2 flaps, 8 with 3 flaps, 6 with 3 flaps, 3 with 5 flaps, and 1 extraordinarily complex wound near the gluteal groove was repaired with 5 myocutaneous flaps and 1 group of fascial flaps. A total of 89 flaps were used for these 28 wounds. (3) The range of repaired tissue defects: 2 cm × 2 cm to 37 cm × 43 cm. the area of myocutaneous flap was 5 cm × 7 cm at the minimum and 36 cm × 21 cm at the maximum.(4) Operation time: in 202 patients with burn injury, 29 operations were performed within 48 h after injury, 86 operations were performed between 2 and 7 d, and 87 operations were performed after 7 d. Fifty-six wounds were first cleared and temporarily covered with allograft skin, and then repaired in phase II; the remaining wounds were repaired in phase I. 3. Observation indexes: survival, texture and appearance of the limb after flap transplantation, coverage of important tissues and functional recovery of the affected limb. Results A total of 332 flaps of various kinds were used to repair 271 wounds in 236 patients, with flap sizes ranging from (2 cm×3 cm) to (24 cm×39 cm). There was one case of complete necrosis of the flap after transplantation and three cases of marginal bruising and necrosis, which were covered by the trauma after skin grafting, and the rest of the flaps were completely viable and the important tissue structures were completely and effectively covered. The rest of the flaps were completely revived and the important tissues were completely covered effectively. 26 cases had soft flap texture and slightly bloated appearance after repair, 17 cases were thinned by re-operation, and the rest of the patients were satisfied with the limb shape. 68 patients with burn trauma on functional parts had no contracture and their functions were restored to different degrees after surgery. Typical case 1. Male, 19 years old, collided with a car while driving a motorcycle at high speed, and the left lower limb was compressed by the motorcycle exhaust pipe at a temperature of about 250 degrees for about 3 minutes, accompanied by severe crush avulsion contusion injury. He was treated at a local hospital and was referred to our department 16 days after the injury due to refusal of amputation. It was found that the left calf was fixed by external fixation brace, the avulsed skin was purple and black, the left calf was completely skin and soft tissue defect from the tibial tuberosity to the level of the inner ankle, the tibiofibula was completely exposed in the lower middle third of the calf in a range of about 20 cm, the anterior lateral tibiofibula was not covered by any tissue, the tibiofibula was visible to the naked eye as yellow-black dry multiple fractures, the posterior gastrocnemius muscle and flounder muscle of this section of the tibiofibula were completely absent, the exposed posterior tibial artery and vein There was a little posterior tibial tissue under the vascular nerve bundle. The dorsolateral aspect of the left foot had approximately 1% TBSA scars and granulation tissue, and the left foot was completely painless to palpation, with limited dorsiflexion and dorsiflexion. The main diagnosis: left calf avulsion injury with thermal compression, left calf soft tissue defect with bone exposure, multiple fractures of the left calf tibia and fibula, and left common peroneal nerve loss with posterior tibial nerve injury. After preoperative management, he underwent debridement + rotational advancement of the left medial gastrocnemius muscle flap + partial amputation of the left fibula + retrograde transfer of the left medial flounder muscle head + fascial flap transfer + mesh implantation to repair the posterior medial bone outgrowth of the left calf on 18 days after the injury; he underwent transfer of the right medial gastrocnemius muscle flap + mesh implantation to repair the anterolateral bone outgrowth of the left calf on 24 days after the injury, and was hospitalized on 46 days after the injury. The patient was discharged from the hospital on day 54 after 38 days of injury with basic coverage of the wound. At 3, 6 and 12 months after discharge, the x-ray of the left calf was reviewed and reported poor healing of the left tibial fracture segment, and at 18 months after discharge, the x-ray showed good healing of the left tibial fracture. The patient’s left foot had no obvious edema, and the sensory recovery started from the center of the left sole to the periphery gradually, and then moved from the dorsal edge of the foot to the center, and the sensation below the ankle joint was basically restored at present. The patient has a slight limp in the left foot when trotting, but the rest of the patient has no obstruction and can drive. Typical case 2: Male, 40 years old, was hit by a truck, resulting in abdominal pain, bilateral hip and bilateral posterior thigh avulsions. He was transferred to the provincial hospital for 50 days for treatment of debridement and anti-infection. Because of the huge trauma that was difficult to repair, the seriousness of local infection that threatened the whole body, and the risk of rupture of large vessels such as femoral arteries that were exposed, the provincial hospital intended to perform amputation of both lower limbs, but the patient refused amputation and was transferred to our hospital 50 days after the injury. The patient refused to amputate the limbs and was transferred to our hospital 50 days after the injury. On examination, he saw: huge trauma of 37×43cm2 area of bilateral gluteal muscles and the posterior side of both thighs, large necrosis of muscle groups, purulent secretions on the trauma surface, bad odor, large amount of exudation, edematous aging granulation tissue at the base, two huge cavities of 260 and 340ml near the left and right gluteal grooves respectively, reaching the deep femur and sciatic bone, with exposed femoral artery and vein inside the cavity, and exposed bilateral sciatic tuberosity and sacrococcyx. The muscle strength of both lower limbs was grade 0, the muscle tone was low, the tendon reflex was not elicited, the pathological reflex was not elicited, and the bilateral femoral artery pulsations were diminished. Main diagnoses on admission: 1. bilateral posterior hip and thigh avulsion injuries; 2. bilateral posterior hip and thigh muscle soft tissue necrosis; 3. bilateral lower limb paraplegia; 4. post-jejuno-intestinal segment resection. Treatment after admission: After admission, the patient underwent treatment such as debridement and wound bacterial culture and systemic anti-infection and nutrition support to adjust the internal environment, and then underwent debridement + retrograde transfer of left semitendinosus muscle flap + local fascial flap transfer + free skin grafting on 67 days after injury, and transfer of broad fascial tensor muscle flap, rectus femoris muscle, suturing muscle flap + local fascial flap transfer + skin grafting on 74 days after injury. The patient’s hip cavity was completely filled with semitendinosus, semimembranosus, rectus femoris and suturing muscles, and the trauma surface of the sciatic tuberosity was completely covered by the broad fascial tensor muscle and local fascial flap, and the rest of the trauma surface was retracted with skin graft. After 32 days of hospitalization, the patient was discharged on 82 days after the injury with no recurrence of the trauma and was able to walk with a cane 13 months after the injury. Discussion Microsurgery has been developed for more than 30 years and free flap grafting is becoming more mature, but even in large units where the technique was first developed nationally and internationally, the incidence of circulatory disorders is still at 4%, and some data suggest that the incidence of free flap blood supply disorders in most medical units still hovers between 5-10% [1]. a summary of 215 patients with soft tissue defects of the lower leg and foot by Pinsolle V suggests that Compared to free flaps local flaps not only have a significantly lower incidence of complications, but also have less severe complications, so that since the 1990s local tipped flaps have replaced free flaps as the main flap for repairing tissue defects of the distal calf and foot. The use of local flaps for wound repair is consistent with the principle of simplicity in wound repair and can be mastered by the majority of burn surgeons in most hospitals. The present results show that 243 of 271 wounds were repaired with a single flap, suggesting that the majority of deep burn wounds can be covered by a single local flap. For example, in typical case 2, we made an incision directly from the front of the patient’s thigh and used the rectus femoris and suture muscle flap to transfer the flap, which has a small transfer radius, consumes less tissue on the way, effectively transfers more tissue, has less impact on the donor area, and meets the physiological needs of the recipient area. In recent years, the method of separating reliable penetrating branches for 180-degree rotation and then advancing the cover is a better solution to the defect of consuming tissues at the local flap tip and is being paid attention to, and some flaps in our group are used in this method. However, the local flap still has the defect of insufficient tissue volume when encountering part of a larger or complex trauma, and Pinsolle V believes that a free flap should be the first choice in this case [2]. Some burn centers in China have more work in this area and have proposed relatively early that the repair of complex and huge wounds can also be solved by combined flap grafting [6], which is consistent with our summary, and 28 wounds in our group have been covered by combined flap grafting. For important structures such as large blood vessels and nerves, they are better covered by blood-rich muscle flaps before superimposed flaps. Therefore, local non-free flaps are basically capable of repairing most wounds of the lower extremity. With the development of anatomy, the flap donor area can be found in almost all parts of the body, more than 70 places, which can satisfy the repair of adjacent traumatic defects. The choice of the specific procedure depends on the clinical experience and skillful application of the grafted flap. Of the 332 flaps used in the repair of 271 traumatic areas of the lower extremity, 193 flaps were used, accounting for 58.1% of the total, including the gastrocnemius muscle flap, the gastrocnemius nerve trophic flap, the saphenous artery flap, and the local fascial flap. The reason for this is that these 4 flaps are mainly used for wounds below the knee joint. Of the 271 wounds in this group, the total number of wounds below the knee joint and below was 234, accounting for 86.3% of the total number of wounds. In today’s civilized society, where the patient’s right to information is increasingly valued, patient participation in the selection of treatment options is increasing. When the lower limb with high-energy-induced disfigurement is torn between limb preservation and amputation, especially when the attempt to preserve the limb is likely to fail, the number of patients who go to several major hospitals hoping to make full use of the potentially disfigured limb to attempt limb preservation without sacrificing normal tissues other than the affected limb is increasing every year, which places a higher demand on the application of local flaps to repair complex trauma of the lower limb.