Six Typical Pitfalls in Pilon Fracture Surgery
Pilon fracture surgery is extremely challenging, requiring not only detailed preoperative planning (surgical approach and appropriate implants), but more importantly, the application of correct instruments for anatomical reduction. This article describes individual but relatively typical pitfalls to help future surgeons improve the final management quality of Pilon fractures.
1. Fibular axial displacement (fibular "banana" deformity), causing the tibia to be in an irreducible state, resulting in axial displacement, abnormal joint surface stress distribution, and early osteoarthritis.
In more than 80% of Pilon fractures, the fibula is also fractured, and the fibula usually also requires reduction and fixation. Like the tibia, the fibula should be reduced and fixed as anatomically accurately as possible. The "fibula-first" principle is typically adopted. Even seemingly simple fibular internal fixation often fails due to axial deviation, particularly referred to as "fibular banana deformity" on lateral radiographs. If this deformity is not identified and corrected intraoperatively, it will lead to secondary tibial malalignment. Even if the articular surface is reconstructed through anatomical reduction, axial deviation may ultimately occur.
Figure 1 a–d: Preoperative radiographs show a C3-type fracture (a). A young patient presented with severe pain and sensory disturbance in the plantar region. The fracture fragments directly compressed the tibial nerve (red arrow, b), and imaging suggested a large posterior malleolar hematoma (thin yellow arrow) (b). The first surgery involved plate fixation of the tibia through a posterolateral approach. Postoperative radiographs (c, d) show pathological flexion deformity of the talus and tibia, caused on one hand by the fibular "banana" deformity and on the other hand by the use of an insufficiently curved T-plate on the posterior tibia. Postoperative CT confirmed the deformity: fibular "banana" deformity (red dashed line) and straight tibial plate (red arrow) (e). This distal tibial deformity resulted in significant anterior displacement of the talus relative to the tibial shaft (f). The second surgery ultimately achieved anatomical reduction of the distal fibular fracture, correcting the distal anterior inclination angle from 74° to 83°.
2. Tibial shortening (especially when the fibula is intact) leading to joint deformity, possibly accompanied by varus deformity, and secondary early osteoarthritis.
The tibia typically undergoes axial compression and shortening. Restoring the correct length of the tibia is crucial for the matching and stability of the ankle mortise. This is also the fundamental prerequisite for achieving anatomical reconstruction of the tibial articular surface. If the tibia remains shortened, its articular fragments usually cannot be properly reduced, resulting in articular surface mismatch. In such cases, a special reduction technique can be employed: Step one, adjust the tibia to the correct height relative to the distal fibula and temporarily fix with Kirschner wires to maintain this position. Subsequently, proceed with reduction and fixation of the tibia. Achieving the correct length often requires significant axial traction, which can be simplified with the aid of a large distractor.
Distal tibial axial compression fracture (C3 type) with intact fibula. Despite the application of an external fixator, the tibia remained severely shortened, causing mismatch between the tibia and distal fibula. g–j: During reconstruction, the primary task is to restore the anatomical length of the tibia. A large distractor is particularly suitable here (red arrow). Reference landmarks are the lateral talar and distal fibular joint lines (red dashed lines). The medial malleolus is also shortened and remains connected to the talus through the intact deltoid ligament (green shaded area). In contrast, the anterolateral tibiofibular (Tillaux-Chaput) fragment (red transparent area) is not shortened because it remains connected to the intact fibula through the intact anterolateral tibiofibular ligament (anterior tibiofibular ligament) (red shaded area) (g). After restoring the anatomical length of the tibia (identifiable by the reconstructed tibiotalar joint congruence relationship (red dashed line)), the talus is temporarily fixed to the distal fibula at this position using threaded Kirschner wires (green dashed arrow). After completing internal fixation through the main anterolateral incision and a medial minimally invasive auxiliary incision, (almost) anatomical reconstruction is achieved. The displaced posterolateral tibiofibular fragment is reduced and fixed with screws (green oval) (k, i).
3. Good joint reduction but not centered on the distal tibial axis, resulting in abnormal joint stress distribution and secondary late osteoarthritis.
Before final tibial fixation, it must be ensured that the tibial articular block (i.e., the talus) is accurately centered relative to the distal tibial shaft axis!
Tibial articular block/talar offset: Radiographs show significant fibular shortening despite the external fixator (blue double arrow on the fibula). The articular block is displaced posterolaterally relative to the tibial shaft axis (green and yellow double arrows) (a, b). Persistent posterolateral offset (green and yellow double arrows; c, d) can be corrected through manual pressure and counter-pressure (simulated by green and yellow wide arrows, respectively).
4. Successful anatomical reduction but inadequate fixation, leading to early instability, loss of reduction, and delayed union or nonunion.
Posteroinferiorly displaced Pilon fracture (C3 type, intact fibula; a, b), after closed reduction, stabilized in the correct position using an external fixator. Preoperative CT shows a large posteromedial weight-bearing fragment extending directly to the tibial tuberosity, as well as a larger vertically oriented anterior fragment (c, d). Intraoperatively, an anteromedial main approach was used, converting the C-type fracture to a B-type fracture (first reducing the longer posterior fragment and fixing it with two anteroposterior lag screws). Subsequently, a Weber clamp was used to reduce the articular block (e, g). Final fixation used only a medial plate and separate screws (f, h), with the larger anterior fragment fixed with only one anteroposterior lag screw, and the anterolateral fragment (Tillaux-Chaput fragment) left unfixed. Comparing the magnified lateral images after surgical reduction (g) and postoperatively (h), widening of the posterior joint space is visible (narrower and wider red arrows), indicating temporary anteroinferior displacement of the talus. The anteroposterior lag screw of the larger anterior fragment appears to have slightly bent. Additionally, there is an unfixed smaller anterior articular fragment (yellow arrow). At six weeks postoperatively (i, j), the anteroinferior displacement of the talus worsened (red double arrow), and the anteroposterior lag screw broke (red arrow). This early secondary displacement with a very poor prognosis could potentially have been avoided through precise preoperative planning and the use of additional anterior/anterolateral plates.
5. Correct anatomical reduction but inadequate medial malleolar fixation (when surgery is performed through an anterolateral approach). Early instability occurs, accompanied by loss of reduction and malunion or nonunion. The medial "auxiliary plate" may also be forgotten.
If these screws (used instead of a buttress plate) already cause fracture displacement intraoperatively, this error can be directly corrected once identified. If not identified in time, it may lead to postoperative complications.
6. Correct anatomical reduction but inadequate fixation: plates that are too short leading to early instability, accompanied by loss of reduction and nonunion or malunion.
Analysis of the problem of using tibial plates that are too short in distal tibia: For a long time, when classical open reduction and internal fixation (ORIF) with plate fixation was used for the distal tibia, all implants were placed through a (fully) open technique. Therefore, to reasonably control the extent of the surgical approach, surgeons were compelled to use the shortest possible plates. It was not until the introduction of percutaneous tibial plate fixation approximately 30 years ago that it became possible to apply longer plates through relatively smaller approaches. For surgeons lacking relevant knowledge or experience, even in contemporary times, selecting plates that are too short in distal tibial fracture treatment can still constitute a technical pitfall.
This fracture was treated more than 20 years ago through an anteromedial approach with double plate fixation (two hollow tubular plates) (c, d). The reduction appeared to be anatomical. However, the fixation was inadequate because plates that were clearly too short were used. The medial plate was fixed with only a single screw (red arrow, c), and the anterior plate was anchored to the proximal main bone fragment with only two screws (partially unicortical; yellow arrow, d). Secondary instability occurred at six weeks postoperatively (e, f). The proximal screw of the medial plate had broken (red arrow, e), the two proximal screws of the anterior plate had loosened (yellow arrow, f), and the third screw, which was initially bicortical (orange dashed arrow, f), had also loosened, leaving only unicortical anchoring.