Pilon fractures have been defined since 1911, and there are endless classification methods. For example, the V type mentioned by Lauger-Hansen in 1963, was a longitudinal compression type. The Ruedi-Allgower and AO/OTA classification are widely used in clinical diagnosis. Both classifications have a certain effect on the pilon fractures, such as the degree of joint comminution and displacement. With the improvement of technology and cognition, Klammer and others proposed that the diagnosis, treatment and postoperative evaluation of pilon fractures should be based on CT three-dimensional reconstruction. Subsequently, Tang Xin proposed the four-column theory of fracture classification based on CT three-dimensional reconstruction. Compared with the classic classification, this theory is more instructive in the selection of clinical surgical incisions and the internal fixation materials.
The four-column classification refers to dividing the inner and outer malleolus into anterior and posterior columns by the line connecting the vertices of the medial and lateral malleolus, and dividing them into medial and lateral columns by the central axis of the sagittal plane of the distal articular surface of the tibia and fibula. There are many ways to fix the medial column, but improper treatment and insecure fixation often cause skin necrosis, failure of internal fixation, traumatic arthritis, and joint dysfunction. As we all know, the cross section of the distal tibia moves from a triangle to a quadrilateral from top to bottom, and the soft tissue coverage of the tibia becomes less and less. However two thirds of the tibia's blood supply comes from intramedullary vessels, and one third comes from the soft tissue attached to the surface.Pilon fractures usually cause intramedullary vascular damage, and Open reduction and internal fixation aggravated the damage of soft tissues and further reduced the blood supply to the distal tibia, leading to non-union, infection, resulting in post-traumatic arthritis and other complications. Kottmeier also found that compared with other fractures, the incidence of nonunion of the distal tibia after surgery is higher. At the same time, Blauth and others proposed the 3P principle in the treatment of pilon fractures. The first point is to protect the blood supply of bone and tissue. Falzarano and others were worried that the medial malleolus itself had less soft tissue and high skin tension. So Kirschner wires, lag screws, hollow nails and other internal fixation materials with less soft tissue peeling were adopted in the fixation. This method avoids the high incidence of complications such as skin necrosis and nonunion caused by internal plants. Compared with the medial column reconstructed by the steel plate, the operation time, blood loss, surgical incision and material cost are reduced, and a good effect has been achieved to a certain extent. However, during the actual operation, Tong found that due to the comminution of the distal tibia, especially the comminution of the lateral cortex of the distal tibia,which makes the proximal ends of lag screws, hollow nails and Kirschner wires relatively loose. At the same time, the author found that the internal bone mass also moved slightly during the flexion and extension of the ankle joint. Jonathan R. Danoff also used bicortical screws to fix the medial column at an angle. After the operation, it was found that although the number of infected patients was greatly reduced, the postoperative weight-bearing pain rate was as high as 11%, and 25% of patients had to change jobs because of postoperative ankle function decline. Although screw fixation reduces the possibility of postoperative skin necrosis, bone exposure, non-union of fractures and delayed union, but also because the patient is late in the ground, functional exercise is delayed, and lung infection, pressure sores, joint stiffness and ankle joint function decreased. Early landing may bring about undesirable consequences such as loss of postoperative reduction, breakage of internal fixation, and re-fracture. Based on the unique physiological structure and weight-bearing function of the ankle joint, a single metal screw or Kirschner wire is more difficult to resist shear force during early functional exercise. Therefore, more and more clinicians are considering the use of strong fixation materials for the medial column that are thinner and less irritating to soft tissues. Hong Gao and others used a multiaxial locking plate to fix the medial column and found that although the plate was thicker than the screw, the occurrence of soft tissue infections was not as high as expected. Feng Ku and Amorosa used tubular steel plate and locking plate respectively and achieved certain curative effects in the reconstruction of the medial column. Adam M. Wegner and others also confirmed that for pilon medial column oblique fractures, the rigidity of the anti-slide plate fixation is four times that of the single cortical fixation screw. By comparing the X-ray and postoperative AOFAS ankle function scores of the observation group and the control group after 3 months and later follow-up, the control group performed early postoperative landing and functional exercises, and some patients suffered loss of postoperative medial column reduction three months after surgery. As for the observation group, due to the strong fixation of the medial column the safety of early weight-bearing activities was ensured. At the same time, BrianAUthgenannt and others also found that under the premise of firm internal fixation, partial load-bearing in the early stage has a better effect on the fracture healing. By assessing the postoperative AOFAS ankle function score, the AOFAS ankle function scores in the observation group in the first, second and third months after the operation were significantly higher than those in the control group, which further indicated that for the reconstruction of the medial column, one-third of the tubular steel plate was more stable than the screw. During the postoperative follow-up, all patients in the observation group had no adverse complications such as soft tissue irritation, infection, and bone nonunion. Li Jianjun, Zhang Hongbin and others analyzed from Tang Xin’s four-pillar theory, axial impact force causes the talus to shift inside the ankle joint anterior and lateral, causing the anterolateral and central area of the distal tibial articular surface to be affected. As the injury increases, the ankle joint Varus and the medial column injury is more serious than the lateral column. And JustinM also found that the proper fixation of the medial column reduces the risk of nonunion after pilon fracture. Based on the principle of early functional exercise, the strong fixation of the medial column becomes more and more important.
Due to the limitations of time and conditions, our follow-up only lasted for half a year. The long-term complications of all patients may not be fully understood. Locking plates and reconstruction plates were not included in the study, and the parallel control group was not set enough. Small sample size brings bias to research. Furthermore, using one-third of the tubular steel plate is economically more expensive than the screw set. However, comprehensively, the author believes that for the reconstruction of the medial column of pilon fractures, one-third of the tubular steel plate has the characteristics of stronger fixation and less soft tissue irritation. The more stable medial column supports each other with the other three columns to form a stronger ankle joint, which ensures the patient's early functional exercise and is more conducive to the fracture healing of the patient. It is the preferred material for the fixation of the medial column of pilon fractures.