Comparative study on the clinical efficacy of small plate assisted anatomic plate and traditional double plate in the treatment of Rüedi and Allgöwer II - III pilon fracture

In this study, we compared the clinical efficacy of small plate assisted anatomic plate and traditional double plate in the treatment of Rüedi and Allgöwer II - III pilon fracture. We found that there was no significant difference in full load time and fracture union time between these two groups. Operation time, intraoperative blood loss, hospital stays were significantly less than those of control group. Furthermore, VAS scores and ankle joint function score were better than those of control group. Moreover, The postoperative complication rate of study group was significantly lower than that of control group. The results revealed that small plate assisted anatomic plate is comparable to traditional double plate in the treatment of pilon fracture in terms of complete loading time, fracture healing time, but the former can shorten the operation time, reduce intraoperative blood loss and effectively reduce the incidence of postoperative complications.

The key to the treatment of pilon fracture are the operation time, reduction of fracture, protection of soft tissue and postoperative management. At present, there are many surgical fixation methods for pilon fractures, including clover plate, anatomic plate, locking compression plate internal fixation [9], minimally invasive percutaneous plate internal fixation [10], limited internal fixation plus external fixation [11] and so on. Since pilon fractures are usually high-energy injuries and often accompanied by serious soft tissue injuries, traditional incisions are long and damaged, and the larger steel plate is placed directly below the incision, which is easy to cause excessive skin tension at the edge of the incision and difficult closure, leading to skin necrosis and incision infection, and thus exposing the steel plate. It has been reported in the literature that the incidence of incision dehiscence and infection through traditional anterior medial approach can be as high as 55% [12]. The mechanical properties of classical clover plate and distal tibial anatomical plate are not good after fixation, and cannot achieve stable, effective and ideal internal fixation. MIPO technique [13] has little soft tissue damage and relatively low wound complications, but it is difficult to reduce high-energy pilon fractures with metaphyseal comminution and articular surface compression, and intraoperative bone grafting is difficult, which affects postoperative ankle function. External fixation scaffolds combined with limited internal fixation can be used to maintain bone length and line of force and reduce the incidence of complications such as infection. However, for type III pilon fractures with severe comminution, the reduction quality is difficult to guarantee, and it is easy to be redisplaced, which leads to long fracture healing time and high incidence of malunion and non-union.

In this study, part of type II and all type III fractures were multi-column fractures involving medial malleolus, anterolateral and medial tibia (Chaput bone block), distal fibula and posterior tibia (WagStaff bone block), and posterior malleolus triangle bone block (Volkmann bone block). A single anterior incision could not take into account all bone blocks. Therefore, when multiple incisions are used, the advantage of smaller plates used in combination can be realized if multiple conventional large plates are still used, which can have a greater impact on the soft tissue. Corresponding incisions were selected for different bone blocks to facilitate the exposure of fracture blocks and facilitate fracture reduction. Due to the use of small plates, the incision is short, 3 to 8 cm in length, and for some patients with longer fracture lines, a proximal auxiliary incision can be added. The incisions should not be separated as far as possible, and the periosteum should be limited to preserve the connection between the skin and subcutaneous and myofascial layers, which has little damage to the blood supply of the flap and is conducive to wound healing and wound related complications. The incision spacing can also be narrowed. In this group, the incision spacing was as short as 3.5 cm without flap necrosis. Some scholars have also reported that 7 cm cannot be used as an absolute indicator as long as the vascular distribution area is carefully considered before surgery to avoid damage to important vascular areas and gentle operation during surgery [12].

The treatment of Pilon fracture requires the rehabilitation of the articular surface and the articular surface of the distal tibia. L-shaped anatomical plate was used to fix the anterior medial column of Pilon fracture, which was used as the main plate to fix the anterior medial column, and a small plate was used to assist in fixing the posterior and medial columns. The small auxiliary steel plate we used has good compliance and easy shaping. After being pressurized by screws, it can fit completely with the bone surface and increase the friction force. Not only that, the volume of small plate is small, can avoid more peel, soft tissue coverage is easy, will not increase the skin tension, conducive to wound healing. It has been reported in the literature that for pilon fractures, ankle movement without weight bearing is required in the early postoperative period and weight bearing in the ground later, regardless of the fixation method. From another aspect also shows that the existing fixing method cannot achieve the effect of strong fixing. The clinical application results show that the small auxiliary plate can achieve stable fixation, effectively prevent the loss of reduction, and allow the ankle joint non-weight-bearing functional exercise in the early stage. Although this study has certain advantages in incision exposure and reduction of incision complications, due to insufficient sample size, the indications need to be further studied and improved by large-scale case and long-term follow-up data. The mechanical strength of pilon fractures assisted by small plates can be further tested by biomechanics. The internal fixation materials for distal tibial fractures can also be miniaturized and individualized, and the effects of different distal fracture blocks can be fixed in a targeted way, so as to achieve the purpose of effective and minimally invasive.