Title : Tibial plateau and pilon fractures similarities and differences
Abstract:
Tibial plateau and pilon fractures have many similarities. These injuries affect two large joints of the lower extremity that bear a large axial support load and have relatively poor soft tissue coverage, which is critical in cases of high-energy injuries and is also of great importance in the choice of surgical approaches for osteosynthesis. Moreover, the intra-articular nature of both fractures suggests, according to modern concepts, that surgical treatment is necessary to achieve complete (anatomical) reduction of articular surfaces and stable fixation of bone fragments to provide early active rehabilitation. However, the attempt to precisely restore the configuration of articular surfaces, as a rule, significantly increases the extent of additional surgical injury as well as the risk of complications. Thus, there is a conflict between the intention to achieve high-quality reduction and the preservation of the biology of the injured area.
This is also seen in the results of treatment. For example, in more than 30% of cases after surgical treatment for tibial plateau fractures, marked displacement of the articular surface fragments remains. This displacement is typical for posterolateral areas of plateau. Current results of surgical treatment for pilon fractures are also far from desirable. Similar to plateau fractures, many authors believe that the main reason for the unsatisfactory outcomes of surgical treatment of comminuted pilon fractures is inadequate reconstruction of the articular surface, which is most often caused by inaccurate reduction of the posterior fragments of the distal part of the tibia.
The first step towards high-quality osteosynthesis is the classification of the fracture. In recent years, there has been a revision of the AO/ASIF and J. Schatzker (1974) classifications used for plateau and pilon fractures, mentioned in relevant literature. This is primarily due to the implementation of CT scanning and three-dimensional visualization of the affected metaepiphyses of the tibia into clinical practice. Due to the wide use of CT in the diagnostic process, it became clear that the incidence of fractures of the tibial plateau with involvement of its posterior parts reaches 60%, which was the main reason for the development of new classifications. In 2010 C.F. Luo et al. proposed a three-column concept, dividing the proximal tibia into medial, lateral, and posterior columns, specifying the localization of lesions and changing the approach to preoperative planning of the discussed fractures. S.M. Chang et al. (2014) divided tibial plateau into four quadrants: anteromedial, anterolateral, posteromedial, and posterolateral. M. Kfuri and J. Schatzker (2018) supplemented the classical classification of J. Schatzker (1974) with CT data. The addition of 3D X-ray imaging data allowed these authors to evaluate the whole range of plateau fractures in both the sagittal and frontal planes, and to classify them in detail with an eye toward possible techniques for reduction and fixation of the bone fragments. As a result, they identified four fragments, each of them can be accessed via a certain approach for direct reduction and fixation of the articular surface fragments, provided that the ligamentous structures responsible for knee joint stability remain intact. The supporting column theory is also used in the classification of fractures of the distal metaepiphysis (pilon) of the tibia. M. Assal (2008) proposed to distinguish medial, lateral, and posterior columns in this area. A detailed classification of pilon fractures based on the analysis of CT data in 108 patients was proposed by C. Topliss et al. (2005), who identified 10 types of fractures depending on the size and positioning of the major articular fragments: lateral, medial, posterior, and central impingement fragment, the so-called "die punch" fragment, combining them into two groups (sagittal and coronal fractures), based on the predominant fracture line. Thus, in pilon and plateau fractures, several classifications can be used in clinical practice. No classification contradicts to any other, but complements them, providing more information about the specific patterns of the bone lesions.
The next stage of the diagnostic process is CT scanning. Many authors recommend performing it right after the initial external fixation. Data obtained allow us to determine the individual fracture patterns of both localizations. We call this approach the 360° preoperative visualization. It allows us to see all the components of injuries to the proximal or distal metaepiphyses of the tibia and fibula, to determine exact surgical approaches, to pick the necessary implants, and to plan their positioning.
Surgical treatment. The current trend is to provide the fastest approach to the zone of greatest interest during osteosynthesis, which, consequently, implies the choice of an adequate surgical approach and, more often, a combination of approaches that are minimally sufficient for limited open direct reduction of intra-articular fracture fragments. Each of the damaged columns is fixed with a separate implant. Number and localization of approaches are limited by the condition of soft tissues and topography of important anatomical structures. It is recommended to maintain a soft tissue bridge at least 7 cm wide between two neighboring longitudinal incisions. Length of the incision is also relevant to the risk of postoperative soft tissue complications. For this reason, many surgeons use a limited-open access technique to minimally expose the impacted or splitted off articular fragment - the zone of interest. It can be stated that in complex plateau and pilon fractures of tibia, we should follow the concept of 360° intraoperative visualization, i.e., perform several small, mostly direct approaches in order to be able to perform direct open anatomical reduction of all damaged bone columns. In comminuted fractures of the discussed localizations, most specialists recommend placing the main buttress plate on the side of the compressed column and fixing the other bone columns with additional conventional or low-profile plates.
Some differences in the approaches to surgical treatment of patients with plateau and pilon fractures are caused, first of all, by a significant difference in the circumference of the shin in the knee and ankle areas, particularly by a significantly smaller volume of soft tissues at the level of the distal metaepiphysis of the tibia. These features of the anatomy should be considered by surgeons when choosing surgical approaches for osteosynthesis. Careful preoperative planning and examination of the patient will allow to take into account the described features of the segment, better understand the fracture pattern, as well as to reduce the risk of postoperative complications.
