Pilon fractures are fractures of the distal 1/3 of the tibia that affect the tibial talar articular surface, often combined with fractures of the inferior fibula and severe soft tissue contusions, and they have a high rate of complications, making Pilon fractures one of the most difficult extremity fractures to treat. There are many treatment methods for Pilon fractures, and a unified consensus has not yet been reached. In recent years, with the continuous updating of treatment concept and improvement of medical equipment, the treatment effect of Pilon fracture has been greatly improved. 1.Treatment principle Pilon fracture is a weight-bearing joint surface fracture of the tibia, and the fragility of the surrounding soft tissues, instability of the comminuted fracture of the epiphysis and even the lower tibial segment, damage to the joint surface and damage to the articular cartilage, treatment is mainly to repair the joint surface, effectively maintain the stability of the fracture repositioning, early joint movement, restore joint function and prevent complications. Bourne et al. reported that the good rate of conservative treatment was only 43%, and the reasons for this were that due to the special anatomical location of the fracture and the requirements for joint function, it was difficult to restore the displacement of the joint surface, poor alignment of the rotational control, easy displacement of the fracture end, and no bone grafting of the epiphyseal defect, The incidence of late complications, such as delayed healing, non-union or deformed healing, is high. Therefore, conservative treatment is suitable for a few type I fractures without displacement, with the joint capsule intact and without obvious dislocation. If possible, limited fixation with percutaneous kerf pins or screws and auxiliary external fixation or strong internal fixation with AO can be used to shorten the external fixation time, early functional exercise, and avoid the possibility of fracture redisplacement by external fixation alone. The “BO” principle for surgical treatment of Pilon fracture has been gradually formed, emphasizing the principles of careful soft tissue exposure, limited debridement of the fracture, indirect reduction technique, early activity and late weight-bearing after stabilization. The aim is to preserve bone and soft tissue viability as much as possible, reposition the articular surface, and provide fixation that allows early movement of the ankle. 3.1. Timing of surgery We believe that surgery should be performed within 8 to 12 hours after injury for good soft tissue conditions and minor fracture injuries, especially for low-energy injuries. For severe soft tissue injury or comminuted fracture, the timing of surgery should be done in two steps: the first step is to stabilize the soft tissue, heel traction or limited fixation of the fibula and external fixation of the brace to maintain the length of the limb, prevent soft tissue contracture, wait for the swelling to subside and soft tissue conditions to permit; the second step is to reposition the tibia by incision and internal fixation, and the time is mostly appropriate between 5d and 3 weeks. If there is a compound injury in other parts of the body, external fixation frame can be used temporarily, and the time is ripe for stage II surgery. In 1963, the AO/ASIF organization formulated the principles of internal fixation for tibial Pilon fracture with incision. Subsequently, four classic steps were proposed for the treatment of Pilon fracture based on this principle: 1) Incisional repositioning of the fibula and internal fixation, which can be used as a reference to restore the length of the distal tibia. 2) Anatomical repositioning of the distal tibial articular surface and fixation with cancellous bone screws. 3) Cancellous bone grafting in the distal tibial bone defect, which can be used to support the articular surface, fill the cavity, stimulate osteogenesis, and promote fracture healing. 4) Plate The medial tibia was fixed. Over the next 20 years, the ORIF method became the main method of treatment for Pilon fractures. Currently, the ORIF approach is only applicable to type I Pilon fractures with good soft tissue conditions and low energy, while open injuries, poor soft tissue conditions, and high-energy type I and II Pilon fractures are relatively contraindicated. With the recent development of minimally invasive surgery, a small incision has been made to implant the plate under the periosteum of the anterior medial tibia to reduce the stripping of soft tissues. (2) Arthroscopy combined with annular external fixation frame With the clinical observation in the past 10 years, many doctors found that most of the patients with Pilon fracture belong to the high-energy type of injury, and most of them are accompanied by more serious soft tissue injury, and the fracture fragments are significantly displaced or even crushed. Some advocate the appropriate use of arthroscopic techniques for restoration of the distal tibial articular surface in combination with a circumferential external fixator. However, for type III Pilon fractures with severe comminution of the articular surface, good repositioning is sometimes difficult to achieve through arthroscopy, and the use of an external fixation brace requires two pins to be placed on the heel bone closest to the ground, which is susceptible to contamination and formation of pin tract infection. Secondly, generally the external fixation brace needs to span the ankle joint, which is unfavorable to the early functional movement of the ankle joint. (3) Limited incisional internal fixation combined with external fixation This method has been a very popular treatment in the last 5 years, especially for type III Pilon fractures. Limited internal fixation refers to the repositioning and internal fixation of the fibula using a small incision and the repositioning of the articular surface of the distal tibia under direct vision, while the repositioning and fixation of the epiphysis relies on various external fixation devices, such as transarticular external fixators. This reduces the incidence of soft tissue complications, and both internal fixation of the fibula and articular surface repositioning under direct vision help to restore limb length and improve the effectiveness of articular surface repositioning. This approach has been reported to significantly reduce the incidence of postoperative complications in type II and III Pilon fractures. It is more suitable for type III Pilon fractures with comminuted articular surfaces than the method using arthroscopy, and can significantly improve articular surface repositioning. Although this method has the same disadvantages of external fixation pin infection and possible prolonged healing time due to the absence of bone grafting and internal fixation of the epiphysis, it is still the method of choice for patients with type II and III Pilon fractures with high-energy type injuries and poor soft tissue conditions. (4) Staged approach to reconstructive internal fixation (ORIF) The fibula is first fixed with an external fixation brace to maintain limb length and line of force, after an intermediate period of 10-21 d to allow adequate improvement of soft tissue conditions to reduce postoperative soft tissue complications; then a standard incisional repositioning and internal fixation of the distal tibial articular surface (ORIF) . The advantage is that it reduces postoperative complications to a certain extent and increases the effectiveness of joint surface repositioning; moreover, a strong internal fixation can shorten the healing time and enable the patient to perform functional exercises early. However, this extended approach can make second-stage incision and repositioning exceptionally difficult due to fibrous connections at the fracture site. And sometimes too much stripping and damage to the soft tissue has to be done, again increasing the risk of soft tissue complications. (5) Arthrofusion Since not all patients with Pilon fractures can achieve complete anatomic reduction, and even if anatomic reduction is possible, the occurrence of traumatic arthritis is inevitable due to necrotic and collapsed changes in the subchondral bone of the joint after the fracture. Therefore, the timing of ankle fusion should be determined according to the specific situation. Generally, it is advisable to perform fusion within 1-2 years after the injury according to the symptoms, signs, x-ray performance and patient’s request. Early complications include wound dehiscence, skin necrosis, superficial or deep infection, mainly due to severe tissue damage caused by trauma, and the local soft tissue tension is too high to cover the distal tibia. Late postoperative complications mainly include delayed fracture healing, bone nonunion, deformed fracture healing, joint stiffness, and traumatic arthritis. For early complications, the fibula can be covered with peroneal muscle and the lateral fibular wound can be covered with free implant to ensure tension-free suturing of the medial tibial wound; for soft tissue injury of type III Pilon fracture, surgery should be postponed after the wound is treated and swelling subsides, and limited internal fixation should be applied to maintain the force line after fracture repositioning, supplemented with external plaster fixation or external fixation brace to reduce the incidence of skin necrosis. Late complications usually require reoperation, or even ankle fusion or amputation. Among 42 patients with severe Pilon fractures treated with limited open reduction internal fixation by J.M. Tan et al, six of them ended up with ankle fusion due to traumatic arthritis, joint stiffness or severe irreparable trauma; thus, it concluded that ankle fusion is a treatment measure to be considered for patients with severe Pilon fractures in young adults. With the update of health concept and the development of modern prosthetic technology, joint fusion and amputation can also be considered for unreconstructable Pilon fractures, but the indications should be strictly and cautiously grasped. In conclusion, from the clinical studies on Pilon fracture treatment reported in the literature, it has been shown that reasonable and perfect preoperative planning, limited internal fixation combined with external fixation, and staged treatment according to soft tissue injury have reduced the incidence of complications caused by soft tissue injury, which has shown its obvious superiority. At the same time, early functional exercise of the ankle joint during treatment and avoidance of prolonged external fixation can minimize complications such as pin tract infection and joint stiffness.