Research on the Morphology and Injury Mechanism of Pilon Fractures

Research on the Morphology and Injury Mechanism of Pilon Fractures | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Systematic Review Research on the Morphology and Injury Mechanism of Pilon Fractures hongquan chen, chong gao, jianwen hou, anzw shao, kefu sun This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8120358/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract This study investigates the link between injury mechanisms and the morphology of high-energy Pilon fractures to support accurate clinical diagnosis and treatment. It includes 192 patients from Lianyungang Second People's Hospital (2010–2024), categorized into five groups based on trauma history and imaging: dorsiflexion, varus, valgus, plantarflexion, and neutral. Two experienced orthopedic surgeons independently assessed X-rays, CT scans, and 3D reconstructions, noting fibular fracture details, tibial fragment distribution, fracture angle, and Topliss classification. Statistical analysis was done using SPSS 25.0, with chi-square or Fisher's exact tests (P < 0.05 for significance). The study identified distinct fracture patterns based on injury mechanisms (P 90° (65%), and coronal Y-type fractures (25%). Varus injuries typically presented "anterolateral + posterolateral + medial + Die-punch" fragments (32.5%) and sagittal split fractures (40%). Valgus injuries were associated with comminuted fibular fractures (64.3%) and tibial coronal V/Y-type fractures (35.7%). Plantarflexion injuries frequently involved posterolateral fragments (61.5%) and fracture angles > 90° (80.8%). Neutral injuries were marked by complex comminuted fractures, with 33.7% showing Die-punch collapse. This study establishes a significant correlation between the morphology of high-energy Pilon fractures and their injury mechanisms, suggesting that preoperative mechanism classification can enhance surgical strategies and minimize complications. Pilon fracture Injury mechanism Fracture morphology Imaging characteristics Biomechanics Precise diagnosis and treatment Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction A pilon fracture is a severe intra-articular fracture of the distal tibia[ 1 , 2 ], typically resulting from high-energy vertical forces, such as those encountered in motor vehicle accidents or skiing incidents. This type of fracture is frequently associated with splitting or collapse of the articular surface and may also involve a concurrent fibular fracture[ 3 – 7 ]. First identified by French radiologist Étienne Destot [ 8 ]in 1911 and named after the French term for "pestle," pilon fractures have consistently posed significant challenges in orthopedic research and treatment. This is due to their complex injury mechanisms and the severity of the intra-articular fractures they entail. Early investigations into Pilon fractures primarily concentrated on characterizing the extent of comminution and displacement, leading to the development of the classic Ruedi-Allgower[ 9 ] and AO classifications[ 10 , 11 ]. Subsequent research revealed that the fracture lines of the distal tibia exhibit varied distribution patterns depending on the direction and magnitude of force transmission, prompting the introduction of the Topliss classification system[ 12 ]. With advancements in imaging technology, contemporary studies have examined Pilon fractures from a three-dimensional perspective, resulting in the proposal of three-column, four-column, and other CT-based classification systems[ 13 – 16 ]. As research has progressed, it has become evident that there is an intrinsic link between the injury mechanism and the morphological presentation of Pilon fractures. Given the previous research's limited exploration of this relationship, the present study seeks to systematically investigate the morphological characteristics of Pilon fractures under different injury mechanisms through retrospective imaging analysis. This investigation aims to provide a reference for preoperative evaluation and enhance the precision of medical treatment. Materials and Methods Inclusion and Exclusion Criteria Inclusion criteria: (1) Patients diagnosed with high-energy Pilon fractures and admitted to The Second People's Hospital of Lianyungang between January 2010 and December 2024; (2) Meeting the diagnostic criteria for high-energy Pilon fractures, as determined by a history of trauma (e.g., falls from significant heights, motor vehicle accidents) and corroborated by imaging data indicating a distal tibial fracture involving the articular surface and resulting in articular collapse; (3)Possessing complete imaging data, including anteroposterior and lateral X-rays of the tibia and fibula, a 1 mm-thickness plain CT scan, and three-dimensional imaging. (Fig. 1 ) Exclusion criteria include: (1) Ankle fractures resulting from low-energy rotational forces, such as those classified as supination-external rotation type according to the Lauge-Hansen classification; (2) Low-energy Pilon fractures, exemplified by falls occurring during routine activities; (3) Pathological fractures, including secondary fractures associated with bone tumors or osteoporotic conditions; (4) Injuries with an indeterminate mechanism, such as those where the injury location cannot be described due to impaired consciousness. General Data A total of 192 patients were enrolled, including 154 males (80.2%) and 38 females (19.8%); aged 14–71 years, with an average of (43.38 ± 12.56) years; causes of injury: 99 cases of fall from height (51.6%), 38 cases of traffic injury (19.8%), 44 cases of falls in daily life (22.9%), 11 cases of heavy object crush injury (5.7%); preoperative time was 5–12 days, with an average of (7.2 ± 2.1) days. All patients completed standardized preoperative imaging evaluation. Imaging Data Collection Grouping Based on Injury Mechanism According to the trauma history and imaging data of patients with Pilon fractures, the Pilon fractures were divided into 5 groups (Fig. 2 ): (1) Dorsiflexion type, where the distal ankle joint was in a dorsiflexed position at the time of injury; (2)Varus type, characterized by the ankle joint being in a varus position at the time of injury; (3) Valgus type, in which the ankle joint was in a valgus position at the time of injury; (4)Plantarflexion type, where the ankle joint was in a plantarflexed position at the time of injury; and (5) Neutral type, where the ankle joint was in a neutral position at the time of injury. Fracture Morphological Indicators Two experienced orthopedic surgeons, each with at least 10 years of experience, independently evaluated the imaging data under double-blind conditions. When their assessments differed, they reached a consensus through departmental discussion. The observations included: The morphology of fibular fractures can be categorized as follows: (1) Fracture level: No fracture, fracture below the tibiofibular syndesmosis, fracture at the level of the tibiofibular syndesmosis, fracture above the tibiofibular syndesmosis; (2) Fracture type: No fracture, avulsion fracture, transverse fracture, oblique fracture, spiral fracture, wedge fracture, comminuted wedge fracture, comminuted fracture, multi-segment comminuted fracture. .Tibial fracture morphology (Fig. 3 ): (1) Fracture fragment distribution: No fracture, anterolateral (Tillaux-Chaput), posterolateral (Volkmann), Die-punch, medial, anterolateral + Die-punch, posterolateral + Die-punch, anterolateral + posterolateral, medial + anterolateral, medial + posterolateral, medial + Die-punch, medial + anterolateral + posterolateral, medial + anterolateral + Die-punch, anterolateral + posterolateral + Die-punch, medial + posterolateral + Die-punch, anterolateral + posterolateral + medial + Die-punch; (2) Medial fragment size: No fracture, avulsion fracture, fracture involving the dome level, fracture involving above the dome; (3) Tibial fracture angle (Fig. 4 ): Less than 90°, greater than 90°, equal to 90° (the angle between the fracture line and the tibial longitudinal axis); (4) Topliss classification (sagittal plane): No fracture, T-type fracture, simple sagittal split fracture, inverted V-type fracture; (5) Topliss classification (coronal plane): No fracture, V-type fracture, Y-type fracture, anterior split fracture, posterior split fracture, simple coronal fracture. Statistical Methods The data processing was conducted using SPSS version 25.0 statistical software. Continuous variables are presented as mean ± standard deviation (x̄ ± s), while categorical variables are reported as the number of cases (percentage) [n (%)]. Inter-group comparisons of fracture morphology were analyzed using the chi-square test, with Fisher's exact probability method applied when the theoretical frequency was less than 5. A p-value of less than 0.05 was deemed statistically significant. Results This study identified significant morphological differences in tibial and fibular fractures across various injury mechanism groups (P < 0.05). The specific characteristics of each group are as follows: Characteristics of Each Injury Mechanism Group Dorsiflexion Type (20 cases, 10.4%) Fibula: 8 cases (40.0%) had no fracture, 11 cases (55.0%) had fractures above the tibiofibular syndesmosis, and 1 case (5.0%) had fractures at the level of the tibiofibular syndesmosis; the main fracture types were transverse (20.0%), oblique (15.0%) and complete comminuted fractures (20.0%). Tibia: The "medial + anterolateral + Die-punch" fragment combination accounted for 45.0% (9/20), and 65.0% (13/20) of the medial fragments involved above the dome; 65.0% (13/20) had a fracture angle > 90°; the Topliss classification in the coronal plane was mainly anterior split (45.0%) and Y-type fracture (25.0%). Varus Type (40 cases, 20.8%) Fibula: 8 cases (20.0%) had no fracture, 21 cases (52.5%) had fractures above the tibiofibular syndesmosis, 10 cases (25.0%) had fractures at the level of the tibiofibular syndesmosis, and 1 case (2.5%) had fractures below the tibiofibular syndesmosis; the main fracture types were transverse (25.0%), complete comminuted (22.5%) and comminuted wedge fractures (15.0%). Tibia: The "anterolateral + posterolateral + medial + Die-punch" combination accounted for 32.5% (13/40), and 67.5% (27/40) of the medial fragments involved above the dome; 57.5% (23/40) had a fracture angle < 90°; the Topliss classification in the sagittal plane was mainly simple sagittal split (40.0%). Valgus Type (14 cases, 7.3%) Fibula:8 cases (57.1%) had fractures above the tibiofibular syndesmosis, and 6 cases (42.9%) had fractures at the level of the tibiofibular syndesmosis; comminuted fractures accounted for 64.3% (9/14), including 5 cases (35.7%) of complete comminution, 2 cases (14.3%) of comminuted wedge, and 2 cases (14.3%) of multi-segment comminution. Tibia: The "medial + anterolateral + posterolateral" fragment combination accounted for 28.6% (4/14), and 64.3% (9/14) of the medial fragments involved above the dome; 57.1% (8/14) had a fracture angle < 90°; the Topliss classification in the coronal plane was V/Y-type fracture (35.7%, 5/14). Plantarflexion Type (26 cases, 13.5%) Fibula: 6 cases (23.1%) had no fracture, 12 cases (46.2%) had fractures above the tibiofibular syndesmosis, 5 cases (19.2%) had fractures at the level of the tibiofibular syndesmosis, and 3 cases (11.5%) had fractures below the tibiofibular syndesmosis; the main fracture types were oblique (38.5%) and comminuted wedge fractures (15.4%). Tibia: The "medial + posterolateral" fragment combination accounted for 26.9% (7/26), and Die-punch collapse accounted for 42.3% (11/26); 50.0% (13/26) of the medial fragments involved above the dome; 80.8% (21/26) had a fracture angle > 90°; the Topliss classification in the coronal plane was mainly posterior split (57.7%). Neutral Type (92 cases, 47.9%) Fibula: 38 cases (41.3%) had no fracture, 37 cases (40.2%) had fractures above the tibiofibular syndesmosis, and 17 cases (18.5%) had fractures at the level of the tibiofibular syndesmosis; comminuted fractures accounted for 30.4% (28/92), including 11 cases (12.0%) of comminuted wedge, 10 cases (10.9%) of complete comminution, and 7 cases (7.6%) of multi-segment comminution. Tibia: The "anterolateral + posterolateral + medial + Die-punch" combination accounted for 33.7% (31/92), and Die-punch collapse accounted for 72.8% (67/92); 77.2% (71/92) of the medial fragments involved above the dome; 48.9% (45/92) had a fracture angle 90°; the Topliss classification in the sagittal plane was mainly T-type (22.8%) and simple sagittal split (20.7%), while the coronal plane was mainly Y-type (29.3%). 3.2 Core Differences in Tibial and Fibular Fracture Morphology(Table 1 ) Table 1 Core Differences in Tibial and Fibular Fracture Morphology Group Fibular Fracture Characteristics (n = 192)) Tibial Fracture Characteristics (n = 192) Dorsiflexion type 55% (11/20) had fractures above the tibiofibular syndesmosis "Medial + anterolateral + Die-punch" combination accounted for 45% (9/20); Fracture angle > 90° accounted for 65% (13/20); Coronal inverted Y-type accounted for 25% (5/20) Varus type 25% (10/40) had fractures at the tibiofibular syndesmosis level "Anterolateral + posterolateral + medial + Die-punch" combination accounted for 32.5% (13/40); Sagittal simple sagittal split accounted for 40% (16/40) Valgus type 57.1% (8/14) had fractures above the tibiofibular syndesmosis "Medial + anterolateral + Die-punch" combination accounted for 28.6% (4/14); Coronal V/Y-type accounted for 35.7% (5/14) Plantarflexion type 46.2% (12/26) had fractures above the tibiofibular syndesmosis Posterolateral bone fragment injury accounted for 61.5% (16/26); Fracture angle > 90° accounted for 80.8% (21/26) Neutral type 40.2% (37/92) had fractures above the tibiofibular syndesmosis Multi-column comminuted fracture accounted for 33.7% (31/92); Die-punch collapse accounted for 72.8% (67/92)72.8%(67/92) Discussion Biological Connection Between Injury Mechanism and Fracture Morphology This study employs quantitative analysis of imaging data from 192 patients with high-energy Pilon fractures to demonstrate that the position of the ankle joint at the time of injury (injury mechanism) is a critical biomechanical factor influencing the morphology of tibial and fibular fractures. These findings align closely with the prevailing perspective on Pilon fractures, which posits that the direction of applied forces determines the orientation of fracture lines, the distribution of fracture fragments, and the extent of comminution. Neutral Type Injury: High-energy axial force, as the predominant mechanism of clinical injury (47.9%), results in the talus directly impacting the dome of the distal tibia, akin to a "pestle." The central column (dome area) endures the highest compressive stress, with finite element analysis indicating peak stress levels of 180–200 MPa[ 17 ]. This stress distribution leads to Die-punch fractures in 73% of patients. Concurrently, the radial expansion of axial force induces secondary burst fractures in surrounding regions (medial, lateral, anterior, posterior), resulting in a complex fracture morphology characterized by "anterolateral + posterolateral + medial + central collapse" (34.1%). These findings align with the conclusion of Court-Brown et al.[ 4 ], which posits that "neutral axial force causes multi-fragment comminution." This study further quantifies the Die-punch collapse rate and fragment combination ratio, thereby addressing specific gaps in previous research. Dorsiflexion-type injury: Ankle joint dorsiflexion results in a 60% reduction in the contact area between the talus and the anterior column of the tibia [ 9 ], thereby concentrating stress on the anterior portion of the distal tibia, specifically in the Tillaux-Chaput fragment region. This stress concentration can lead to a combined "anterolateral + central column" injury, with 45% of cases exhibiting "medial + anterolateral + Die-punch" injuries. Conversely, during plantarflexion, the combined effects of vertical and external rotational forces transmit axial loads along the fibula[ 18 ], leading to fractures above the tibiofibular syndesmosis in 55.0% of patients. Plantarflexion Type Injury: Plantarflexion of the ankle joint results in the talus impacting the posterior column of the tibia, specifically in the Volkmann fragment area. This action predominantly induces shear stress, leading to a fracture angle greater than 90° in 80.8% of patients and a posterolateral column injury rate of 61.5% (16 out of 26 cases). These findings align closely with the conclusions drawn by Wang et al[ 19 ]., who demonstrated through cadaveric specimen experiments that the stress concentration coefficient of the posterior column in the plantarflexed position is 1.8 times higher than in the neutral position. Concurrently, Lou and colleagues [ 8 , 9 ] propose that this injury pattern is attributable to axial compression combined with rotational force, which compresses or even displaces the posterior articular surface of the tibia. This mechanism results in the posterior fragment extending to the posterior or medial malleolus, corroborating the occurrence of medial and posterolateral fracture fragments observed in 26.9% of cases in this study. Varus type Injury: A varus force results in the compression of the medial edge of the talus against the medial column of the tibia, leading to the formation of a "large medial column fragment (67.5% involving above the dome) and a simple tension fracture of the lateral column (transverse/wedge accounting for 40%)." This pattern reflects the mechanical principle of "medial compression and lateral tension," which aligns with the finite element analysis conducted by Zhang et al. [ 10 ]. In pediatric varus-type Pilon fractures, particular attention should be given to the lateral ligament complex and avulsion fractures, as these have a high rate of missed diagnosis. This fracture type predominantly manifests as sagittal fractures (40% simple sagittal split) and evolves into an inverted V/T configuration with increased force [ 12 ]. Valgus type Injury:A valgus force induces an outward and upward displacement of the talus, leading to complete comminution and a 28.6% collapse of the lateral distal tibia. Concurrently, the transmission of force results in fibular fractures predominantly occurring above the tibiofibular syndesmosis, corroborating the findings of Zhang et al[ 17 ]. through 3D CT reconstruction. This study, however, provides a more detailed characterization: 57.1% of fibular fractures in the valgus group are situated above the tibiofibular syndesmosis, and 64.3% exhibit comminution. This suggests that under valgus force, the fibula is subjected not only to axial loading but also to shear forces in the abduction direction, resulting in more complex fracture morphologies. Additionally, the valgus type is frequently associated with coronal fractures, which progressively evolve from simple coronal fractures to V/Y types as the force increases, with 35.7% exhibiting the coronal V/Y type [ 12 ]. Correspondence and Supplement to Existing Classification Systems Ruedi-Allgower classification[ 9 , 20 ]: As the most established classification system for Pilon fractures, it primarily addresses the extent of comminution and displacement associated with these fractures, exerting a widespread and significant influence. However, its application is constrained by technological limitations, as it relies solely on X-ray imaging to assess fracture displacement and comminution. This study employs computed tomography (CT) and three-dimensional imaging technologies to enhance the evaluative scope of the classification system by incorporating quantitative metrics such as fragment configuration and fracture line analysis. AO classification: In 1987, Müller and colleagues [ 11 ] endeavored to develop a comprehensive classification system for long bone fractures, known as the AO classification. This system categorizes Pilon fractures into three types—A, B, and C—based on the involvement of the articular surface. While this classification effectively describes the fracture morphology of Pilon fractures, it exhibits a weak correlation between the three types and fails to adequately reflect the severity of the fractures [ 21 ]. Additionally, the classification does not account for injury mechanisms and merely describes the comminution of the articular surface. This study addresses these limitations by correlating fracture morphology with different injury mechanisms, thereby providing a more comprehensive understanding. Five-column classification: Recently, In recent years, Liu et al. [ 15 ] introduced a novel classification system for Pilon fracture morphology utilizing finite element analysis. This system categorizes Pilon fractures into five distinct columns based on three primary injury mechanisms, thereby delineating fracture morphology through columnar division. While the initial classification establishes a correlation between injury mechanisms and morphological characteristics, the present study expands upon this framework by examining five injury mechanisms. It integrates additional parameters, such as fracture lines and angles, to enhance the granularity and precision of the classification system. Anterior/posterior Pilon fracture subtypes: Cao Junmin et al. [ 22 ] characterized the "anterior Pilon fracture" as primarily involving an "anterior column split with central collapse." In this study, 80% of dorsiflexion-type fractures exhibited this feature. The authors further quantified the occurrence of the "anterolateral and central column" combination at 45%, suggesting that the presence of an anterolateral fragment, Die-punch collapse, and medial fragment extending above the dome on CT imaging can serve as diagnostic criteria for anterior Pilon fractures. Conversely, the study identified that 61.5% of plantarflexion-type injuries involved the posterolateral column, aligning with the "posterior Pilon fracture" described by Lou et al. [ 7 , 8 ]. This finding is complemented by a prognostic indicator, whereby a fracture angle greater than 90° is associated with a 2.3-fold increased risk of postoperative nonunion of the posterior malleolus [ 23 ]. CT classification:The classification system introduced by Leonetti et al. [ 24 ], which utilizes CT scans, aims to detail the extent of articular surface involvement by fractures, the displacement and number of joint fragments, the positioning of primary fracture lines, and the areas of comminution. While this system provides a thorough representation of the comminution of the distal tibial articular surface, it lacks consideration of the injury mechanism and fails to elucidate the concept of fracture fragment combinations. The present study successfully addresses these deficiencies. Clinical Application Value Optimization of preoperative evaluation: The identification of characteristic fracture fragments through three-dimensional CT reconstruction can facilitate the retrospective inference of injury mechanisms. For instance, a "posterolateral fragment with a fracture angle greater than 90°" is indicative of a plantarflexion-type injury, necessitating MRI evaluation of the posterior ankle fracture prior to surgical intervention. Conversely, the presence of a "lateral comminuted fragment with a fracture located above the tibiofibular syndesmosis" suggests a valgus-type injury, warranting careful assessment for potential diastasis of the tibiofibular syndesmosis[ 25 ]. Additionally, the combination of "posteromedial and anterolateral fragments" necessitates evaluation of the risk for postoperative entrapment of the tibialis posterior tendon, as this could adversely impact postoperative functional outcomes [ 26 ]. Study Limitations Retrospective study bias:This study exclusively examines fracture morphology and does not include a longitudinal assessment of postoperative joint function outcomes, such as the American Orthopaedic Foot & Ankle Society (AOFAS) score, or complications, including traumatic arthritis and nonunion. Future studies with a minimum follow-up period of two years are necessary to elucidate the comprehensive correlation chain of "mechanism-morphology-prognosis." Lack of biomechanical verification: The correlation between "stress-fracture morphology" proposed in this study, derived from clinical observations, has yet to be validated through dynamic mechanical loading experiments using cadaveric specimens[ 38 ] or 3D-printed models. Future research should incorporate the MTS mechanical testing system[ 39 ] to simulate force loading at various positions, thereby quantifying the stress distribution and determining the fracture threshold for each column. Lack of long-term prognosis data: This study is limited to the analysis of fracture morphology and does not include longitudinal assessment of postoperative joint function, such as the American Orthopaedic Foot & Ankle Society (AOFAS) score, or complications, such as traumatic arthritis and nonunion, in patients. Future studies with a follow-up period of at least two years are required to elucidate the comprehensive correlation chain encompassing "mechanism, morphology, and prognosis." Formulation of individualized surgical strategies: Based on the strategic selection of the approach and fixation plan, the following methods are employed:(1)Plantarflexion type:A modified posteromedial approach, involving an incision medial to the posterior tibial artery, was employed to expose the flexor hallucis longus tendon. This technique allowed for complete visualization of the Volkmann fragment and the medial fragment, facilitating clear observation of the fracture line orientation, the number of fragments, and the degree of displacement[ 27 , 28 ]. Direct visualization during reduction was utilized to minimize the risk of traumatic arthritis[ 29 ].༈2༉Dorsiflexion type: Complex anterior Pilon fractures are associated with a high complication rate when utilizing combined anterolateral and anteromedial surgical approaches. The choice of surgical technique is determined by the presence of "anterior/anterolateral fragments (Tillaux-Chaput)" or "posterolateral fragments (Volkmann)." The efficacy and safety of this strategy are assessed, demonstrating that anterolateral fragments (Tillaux-Chaput) can be accurately fixed[ 30 ].༈3༉Valgus Type: In cases of comminuted fibular fractures accompanied by lateral tibial collapse[ 31 ], lateral plate fixation has been shown to yield optimal outcomes [ 31 ]. The anterolateral or Bohler approach may be employed to achieve comprehensive exposure of the fibular fracture, the lateral tibial articular surface, the Tillaux-Chaput fragments, and the tibiofibular syndesmosis. However, it is imperative to exercise caution to protect the superficial peroneal nerve and the perforators of the peroneal artery [ 32 ]. In instances where the condition of the soft tissue is suboptimal, a staged treatment protocol should be implemented. This involves maintaining alignment with an external fixator during the initial stage, followed by reduction through double lateral and anterolateral incisions in the subsequent stage, thereby minimizing the risk of soft tissue necrosis.༈4༉Neutral Type: The sequence of "first reducing the peripheral fragment framework, then prying and reducing the central collapse[ 33 ]", combined with porous tantalum metal bone grafting to support the central column, the reduction loss rate is only 3.2% (significantly lower than 15.6% of autologous bone grafting); ༈5༉Varus Type: Varus stress contributes to the development of an ankle varus deformity, while the application of a medial plate can inhibit the progression of this deformity[ 34 , 35 ]. Utilizing an anteromedial approach to the distal tibia facilitates enhanced exposure of the central tibial region and the medial articular surface. Implementing early rigid internal fixation of the medial fragment[ 36 , 37 ], combined with partial weight-bearing to deliver appropriate stress stimulation, can significantly enhance patient prognosis and minimize postoperative complications. Conclusion A significant and predictable correlation exists between the fracture morphology of the distal tibia in high-energy Pilon fractures and the specific position of the ankle joint at the time of injury, which is determined by the injury mechanism. The five primary injury mechanisms—dorsiflexion, varus, valgus, plantarflexion, and neutral positions—result in distinct fracture types, fragment distribution patterns, and fracture line morphologies. This correspondence between mechanism and morphology profoundly reflects the biomechanical response of various regions of the distal tibia under specific loading conditions. The findings of this study enhance the theoretical foundation for understanding the morphological complexity of Pilon fractures in relation to injury mechanisms and provide objective evidence for clinicians to predict fracture characteristics. This understanding facilitates the optimization of preoperative planning and surgical strategies through detailed imaging analysis. Ultimately, the goal is to achieve more precise fracture reduction and stable fixation, thereby improving the functional prognosis for patients. Future research could incorporate more sophisticated finite element mechanical analysis or cadaveric mechanical analysis to enhance the comprehensive understanding of injury mechanisms. Declarations Ethical Approval and Informed Consent This study received ethical approval from the Ethics Committee of The Second People's Hospital of Lianyungang, under approval number AF/SC-08/01.0. Informed consent was obtained from all participants, who signed the necessary consent forms. All research procedures involving human participants adhere to the ethical standards set forth by the institutional research committee and are in accordance with the 1964 Helsinki Declaration and its subsequent amendments or equivalent ethical guidelines. Funding This research was funded by the Scientific Research Development Fund of Kangda College, Nanjing Medical University, under project number KD2024KYJJ050. Author Contribution H.Q .Ccontributed to formal analysis, funding acquisition, software development, and the initial drafting of the manuscript. C. G was responsible for formal analysis and investigation. J.W.H handled data curation, software development, and funding acquisition. A.Z. S was involved in methodology development and project administration. K.F. S contributed to methodology development, project administration, and the review and editing of the manuscript. Conflict of Interest Statement All authors of this study confirm that there are no identifiable financial conflicts of interest, personal relationships, or other potential influencing factors that could interfere with the objectivity of the research, the presentation of results, or the derivation of conclusions. All authors take full responsibility for the authenticity of the research data, analysis results, and the final manuscript. Ethical Statement This study has been approved by the Ethics Committee of The Second People's Hospital of Lianyungang, with the approval number AF/SC-08/01.0. All participants in this study have signed written informed consent forms, fully understanding the purpose, procedures, and potential risks of the research. 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Zhongguo Gu Shang 24:470–473 Zhang GM, Ruan ZY, Yi LL, Yin HL, Pan FG (2018) Morphological analysis and three-dimensional finite element analysis of injury mechanism of posterior malleolus fracture variant of Pilon. Zhonghua Shi Yan Wai Ke Za Zhi 35:2035–2038 Zhu G, Cao S, Zhu J, Yuan C, Wang Z, Huang J, Ma X, Wang X (2024) Combined vertical and external rotational force in plantarflexion position produces posterior pilon fracture: A preliminary cadaveric study. Foot Ankle Surg 30:394–399 Wang J, Wang X, Xie L, Zheng W, Chen H, Cai L (2020) Comparison of radiographs and CT features between posterior Pilon fracture and posterior malleolus fracture: a retrospective cohort study. Br J Radiol 93:20191030 Ovadia DN, Beals RK (1986) Fractures of the tibial plafond. J Bone Joint Surg Am 68:543–551 Swiontkowski MF, Sands AK, Agel J, Diab M, Schwappach JR, Kreder HJ (1997) Interobserver variation in the AO/OTA fracture classification system for pilon fractures: is there a problem? J Orthop Trauma 11:467–470 Cao JM, Wang Q, Wang Y, Chen J, Jiang HP, Zhang PJ (2023) Imaging characteristics and surgical efficacy analysis of anterior Pilon fractures. Shi Yong Gu Ke Za Zhi 29:747–752 Urrutia T, Faundez J, Vidal C, Palma J, Filippi J (2025) Visualizing access in pilon fractures: A comparative study of eight approaches. Foot Ankle Surg 31:539–546 Leonetti D, Tigani D (2017) Pilon fractures: A new classification system based on CT-scan. Injury 48:2311–2317 Yeung TW, Chan CY, Chan WC, Yeung YN, Yuen MK (2015) Can pre-operative axial CT imaging predict syndesmosis instability in patients sustaining ankle fractures? Seven years' experience in a tertiary trauma center. Skeletal Radiol 44:823–829 Labrum JTt, Gallagher B, Boyce RH (2023) Injury Pattern Recognition and Surgical Technique of Pilon Fracture Reduction With Posterior Tibial Tendon Incarceration. J Orthop Trauma 37:e227–e231 Switaj PJ, Weatherford B, Fuchs D, Rosenthal B, Pang E, Kadakia AR (2014) Evaluation of posterior malleolar fractures and the posterior pilon variant in operatively treated ankle fractures. Foot Ankle Int 35:886–895 Bacon S, Smith WR, Morgan SJ, Hasenboehler E, Philips G, Williams A, Ziran BH, Stahel PF (2008) A retrospective analysis of comminuted intra-articular fractures of the tibial plafond: Open reduction and internal fixation versus external Ilizarov fixation. Injury 39:196–202 Tenenbaum S, Shazar N, Bruck N, Bariteau J (2017) Posterior Malleolus Fractures. Orthop Clin North Am 48:81–89 Di Giorgio L, Touloupakis G, Theodorakis E, Sodano L (2013) A two-choice strategy through a medial tibial approach for the treatment of pilon fractures with posterior or anterior fragmentation. Chin J Traumatol 16:272–276 Sirkin MS (2007) Plating of tibial pilon fractures. Am J Orthop (Belle Mead NJ) 36:13–17 Femino JE, Vaseenon T (2009) The direct lateral approach to the distal tibia and fibula: a single incision technique for distal tibial and pilon fractures. Iowa Orthop J 29:143–148 Haraguchi N, Toga H, Shiba N, Kato F (2007) Avulsion fracture of the lateral ankle ligament complex in severe inversion injury: incidence and clinical outcome. Am J Sports Med 35:1144–1152 Helfet DL, Haas NP, Schatzker J, Matter P, Moser R, Hanson B (2003) AO philosophy and principles of fracture management-its evolution and evaluation. J Bone Joint Surg Am 85:1156–1160 Scolaro J, Ahn J (2011) Pilon fractures. Clin Orthop Relat Res 469:621–623 Miller TL, Kaeding CC, Rodeo SA (2020) Emerging Options for Biologic Enhancement of Stress Fracture Healing in Athletes. J Am Acad Orthop Surg 28:1–9 Haller JM, Holt D, Rothberg DL, Kubiak EN, Higgins TF (2016) Does Early versus Delayed Spanning External Fixation Impact Complication Rates for High-energy Tibial Plateau and Plafond Fractures? Clin Orthop Relat Res 474:1436–1444 Ott N, Harbrecht A, Hackl M, Leschinger T, Knifka J, Müller LP, Wegmann K (2021) Inducing pilon fractures in human cadaveric specimens depending on the injury mechanism: a fracture simulation. Arch Orthop Trauma Surg 141:837–844 Ramlee MH, Sulong MA, Garcia-Nieto E, Penaranda DA, Felip AR, Kadir MRA (2018) Biomechanical features of six design of the delta external fixator for treating Pilon fracture: a finite element study. Med Biol Eng Comput 56:1925–1938 Additional Declarations No competing interests reported. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8120358","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Systematic Review","associatedPublications":[],"authors":[{"id":559829702,"identity":"258ae993-6790-48fd-9fe1-28f6fe55e920","order_by":0,"name":"hongquan chen","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA6klEQVRIiWNgGAWjYDACCQYGZjjnQwGpWhhnGJCqhZmHGC38s5uPPS6ouGPXdyP52WMbg8N2/RIJjB8+5uCx5M6xdOMZZ54lz7yRZm6cY3A4eeaMBGbJmdtwazGQyDGT5m07nGxwI8FMGqQFyGBj5sWrJf8bVEv6N2kLoBZ7wlpy2EBa7AxuAK1jAPrFQIKAFokbaWbSPGcOJ0ieeVMm2WOQniBx5mEzXr/wz0h+Js1Tcdie73j6NokfFdb2/O3JBz98xKMFBhIbDoDp5sQGgcQGwuqBwJ4BoqXOnoH/AFE6RsEoGAWjYOQAAMKXUoT/gqeFAAAAAElFTkSuQmCC","orcid":"","institution":"The Affiliated Hospital of Kangda College, Nanjing Medical University (Clinical Medical College, Teaching Hospital)","correspondingAuthor":true,"prefix":"","firstName":"hongquan","middleName":"","lastName":"chen","suffix":""},{"id":559829703,"identity":"ccb4e89b-f9ee-4640-a3b6-e3fb7395e71c","order_by":1,"name":"chong gao","email":"","orcid":"","institution":"Affiliated Lianyungang Clinical College of Nantong University","correspondingAuthor":false,"prefix":"","firstName":"chong","middleName":"","lastName":"gao","suffix":""},{"id":559829704,"identity":"5737d0fc-79af-4093-93d4-bfb3b9d7bc06","order_by":2,"name":"jianwen hou","email":"","orcid":"","institution":"Affiliated Lianyungang Clinical College of Nantong University","correspondingAuthor":false,"prefix":"","firstName":"jianwen","middleName":"","lastName":"hou","suffix":""},{"id":559829705,"identity":"68da9040-8f80-4265-8bab-df350430da93","order_by":3,"name":"anzw shao","email":"","orcid":"","institution":"Affiliated Lianyungang Clinical College of Nantong University","correspondingAuthor":false,"prefix":"","firstName":"anzw","middleName":"","lastName":"shao","suffix":""},{"id":559829706,"identity":"4b65e2ab-d8a2-4253-9336-1d031f40d1a7","order_by":4,"name":"kefu sun","email":"","orcid":"","institution":"Affiliated Lianyungang Clinical College of Nantong University","correspondingAuthor":false,"prefix":"","firstName":"kefu","middleName":"","lastName":"sun","suffix":""}],"badges":[],"createdAt":"2025-11-15 07:53:33","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8120358/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8120358/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":98293800,"identity":"5a34f119-b88b-4b28-917b-7ad6457040b3","added_by":"auto","created_at":"2025-12-16 09:03:41","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":122206,"visible":true,"origin":"","legend":"\u003cp\u003eFlow chart of inclusion criteria.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-8120358/v1/c9a0add63361e33684616cbc.png"},{"id":98442392,"identity":"affea0b6-bddf-4566-b762-3b6ab704b32e","added_by":"auto","created_at":"2025-12-17 17:10:14","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":312933,"visible":true,"origin":"","legend":"\u003cp\u003eA: Valgus type injury. B: Varus type injury. C: Neutral type injury. D: Dorsiflexion type injury. E: Plantarflexion type injury.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-8120358/v1/aaae0ad38d95394c5bb72ea7.png"},{"id":98435154,"identity":"19c1b61f-850e-4b27-8b72-678cc737c0ed","added_by":"auto","created_at":"2025-12-17 16:53:13","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":344805,"visible":true,"origin":"","legend":"\u003cp\u003eTibial fracture angle: The angle between the tibiofibular axis and the main fracture line direction from the joint center. (The tibial fracture angle in this figure is \u0026lt; 90°)\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-8120358/v1/972c112571f961e14dd7324e.png"},{"id":98293803,"identity":"2ce502e4-b033-4db6-a085-09305594657c","added_by":"auto","created_at":"2025-12-16 09:03:41","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":172212,"visible":true,"origin":"","legend":"\u003cp\u003e（1）Anterolateral bone fragment (Tillaux-Chaput).）osterolateral bone fragment (Volkmann).3） Medial bone fragment.4）Compressed bone fragment (Die-punch).\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-8120358/v1/8052f8f0b5ae5f81e27fef28.png"},{"id":98447478,"identity":"4cc94fee-6e0a-4328-8db1-8f8f5ebffe3b","added_by":"auto","created_at":"2025-12-17 17:25:57","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1425597,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8120358/v1/1f7e4b72-7384-4104-9195-b5157df32110.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Research on the Morphology and Injury Mechanism of Pilon Fractures","fulltext":[{"header":"Introduction","content":"\u003cp\u003eA pilon fracture is a severe intra-articular fracture of the distal tibia[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e], typically resulting from high-energy vertical forces, such as those encountered in motor vehicle accidents or skiing incidents. This type of fracture is frequently associated with splitting or collapse of the articular surface and may also involve a concurrent fibular fracture[\u003cspan additionalcitationids=\"CR4 CR5 CR6\" citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. First identified by French radiologist \u0026Eacute;tienne Destot [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]in 1911 and named after the French term for \"pestle,\" pilon fractures have consistently posed significant challenges in orthopedic research and treatment. This is due to their complex injury mechanisms and the severity of the intra-articular fractures they entail.\u003c/p\u003e \u003cp\u003eEarly investigations into Pilon fractures primarily concentrated on characterizing the extent of comminution and displacement, leading to the development of the classic Ruedi-Allgower[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e] and AO classifications[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Subsequent research revealed that the fracture lines of the distal tibia exhibit varied distribution patterns depending on the direction and magnitude of force transmission, prompting the introduction of the Topliss classification system[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. With advancements in imaging technology, contemporary studies have examined Pilon fractures from a three-dimensional perspective, resulting in the proposal of three-column, four-column, and other CT-based classification systems[\u003cspan additionalcitationids=\"CR14 CR15\" citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. As research has progressed, it has become evident that there is an intrinsic link between the injury mechanism and the morphological presentation of Pilon fractures. Given the previous research's limited exploration of this relationship, the present study seeks to systematically investigate the morphological characteristics of Pilon fractures under different injury mechanisms through retrospective imaging analysis. This investigation aims to provide a reference for preoperative evaluation and enhance the precision of medical treatment.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cp\u003eInclusion and Exclusion Criteria\u003c/p\u003e \u003cp\u003eInclusion criteria: (1) Patients diagnosed with high-energy Pilon fractures and admitted to The Second People's Hospital of Lianyungang between January 2010 and December 2024; (2) Meeting the diagnostic criteria for high-energy Pilon fractures, as determined by a history of trauma (e.g., falls from significant heights, motor vehicle accidents) and corroborated by imaging data indicating a distal tibial fracture involving the articular surface and resulting in articular collapse; (3)Possessing complete imaging data, including anteroposterior and lateral X-rays of the tibia and fibula, a 1 mm-thickness plain CT scan, and three-dimensional imaging. (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e)\u003c/p\u003e \u003cp\u003eExclusion criteria include: (1) Ankle fractures resulting from low-energy rotational forces, such as those classified as supination-external rotation type according to the Lauge-Hansen classification; (2) Low-energy Pilon fractures, exemplified by falls occurring during routine activities; (3) Pathological fractures, including secondary fractures associated with bone tumors or osteoporotic conditions; (4) Injuries with an indeterminate mechanism, such as those where the injury location cannot be described due to impaired consciousness.\u003c/p\u003e \u003cp\u003eGeneral Data\u003c/p\u003e \u003cp\u003eA total of 192 patients were enrolled, including 154 males (80.2%) and 38 females (19.8%); aged 14\u0026ndash;71 years, with an average of (43.38\u0026thinsp;\u0026plusmn;\u0026thinsp;12.56) years; causes of injury: 99 cases of fall from height (51.6%), 38 cases of traffic injury (19.8%), 44 cases of falls in daily life (22.9%), 11 cases of heavy object crush injury (5.7%); preoperative time was 5\u0026ndash;12 days, with an average of (7.2\u0026thinsp;\u0026plusmn;\u0026thinsp;2.1) days. All patients completed standardized preoperative imaging evaluation.\u003c/p\u003e \u003cp\u003eImaging Data Collection\u003c/p\u003e \u003cp\u003eGrouping Based on Injury Mechanism\u003c/p\u003e \u003cp\u003eAccording to the trauma history and imaging data of patients with Pilon fractures, the Pilon fractures were divided into 5 groups (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e): (1) Dorsiflexion type, where the distal ankle joint was in a dorsiflexed position at the time of injury; (2)Varus type, characterized by the ankle joint being in a varus position at the time of injury; (3) Valgus type, in which the ankle joint was in a valgus position at the time of injury; (4)Plantarflexion type, where the ankle joint was in a plantarflexed position at the time of injury; and (5) Neutral type, where the ankle joint was in a neutral position at the time of injury.\u003c/p\u003e \u003cp\u003eFracture Morphological Indicators\u003c/p\u003e \u003cp\u003eTwo experienced orthopedic surgeons, each with at least 10 years of experience, independently evaluated the imaging data under double-blind conditions. When their assessments differed, they reached a consensus through departmental discussion. The observations included:\u003c/p\u003e \u003cp\u003eThe morphology of fibular fractures can be categorized as follows:\u003c/p\u003e \u003cp\u003e(1) Fracture level: No fracture, fracture below the tibiofibular syndesmosis, fracture at the level of the tibiofibular syndesmosis, fracture above the tibiofibular syndesmosis;\u003c/p\u003e \u003cp\u003e(2) Fracture type: No fracture, avulsion fracture, transverse fracture, oblique fracture, spiral fracture, wedge fracture, comminuted wedge fracture, comminuted fracture, multi-segment comminuted fracture.\u003c/p\u003e \u003cp\u003e.Tibial fracture morphology (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e):\u003c/p\u003e \u003cp\u003e(1) Fracture fragment distribution: No fracture, anterolateral (Tillaux-Chaput), posterolateral (Volkmann), Die-punch, medial, anterolateral\u0026thinsp;+\u0026thinsp;Die-punch, posterolateral\u0026thinsp;+\u0026thinsp;Die-punch, anterolateral\u0026thinsp;+\u0026thinsp;posterolateral, medial\u0026thinsp;+\u0026thinsp;anterolateral, medial\u0026thinsp;+\u0026thinsp;posterolateral, medial\u0026thinsp;+\u0026thinsp;Die-punch, medial\u0026thinsp;+\u0026thinsp;anterolateral\u0026thinsp;+\u0026thinsp;posterolateral, medial\u0026thinsp;+\u0026thinsp;anterolateral\u0026thinsp;+\u0026thinsp;Die-punch, anterolateral\u0026thinsp;+\u0026thinsp;posterolateral\u0026thinsp;+\u0026thinsp;Die-punch, medial\u0026thinsp;+\u0026thinsp;posterolateral\u0026thinsp;+\u0026thinsp;Die-punch, anterolateral\u0026thinsp;+\u0026thinsp;posterolateral\u0026thinsp;+\u0026thinsp;medial\u0026thinsp;+\u0026thinsp;Die-punch;\u003c/p\u003e \u003cp\u003e(2) Medial fragment size: No fracture, avulsion fracture, fracture involving the dome level, fracture involving above the dome;\u003c/p\u003e \u003cp\u003e(3) Tibial fracture angle (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e): Less than 90\u0026deg;, greater than 90\u0026deg;, equal to 90\u0026deg; (the angle between the fracture line and the tibial longitudinal axis);\u003c/p\u003e \u003cp\u003e(4) Topliss classification (sagittal plane): No fracture, T-type fracture, simple sagittal split fracture, inverted V-type fracture;\u003c/p\u003e \u003cp\u003e(5) Topliss classification (coronal plane): No fracture, V-type fracture, Y-type fracture, anterior split fracture, posterior split fracture, simple coronal fracture.\u003c/p\u003e \u003cp\u003eStatistical Methods\u003c/p\u003e \u003cp\u003eThe data processing was conducted using SPSS version 25.0 statistical software. Continuous variables are presented as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation (x̄ \u0026plusmn; s), while categorical variables are reported as the number of cases (percentage) [n (%)]. Inter-group comparisons of fracture morphology were analyzed using the chi-square test, with Fisher's exact probability method applied when the theoretical frequency was less than 5. A p-value of less than 0.05 was deemed statistically significant.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eThis study identified significant morphological differences in tibial and fibular fractures across various injury mechanism groups (P\u0026thinsp;\u0026lt;\u0026thinsp;0.05). The specific characteristics of each group are as follows:\u003c/p\u003e \u003cp\u003eCharacteristics of Each Injury Mechanism Group\u003c/p\u003e \u003cp\u003eDorsiflexion Type (20 cases, 10.4%)\u003c/p\u003e \u003cp\u003eFibula: 8 cases (40.0%) had no fracture, 11 cases (55.0%) had fractures above the tibiofibular syndesmosis, and 1 case (5.0%) had fractures at the level of the tibiofibular syndesmosis; the main fracture types were transverse (20.0%), oblique (15.0%) and complete comminuted fractures (20.0%).\u003c/p\u003e \u003cp\u003eTibia: The \"medial\u0026thinsp;+\u0026thinsp;anterolateral\u0026thinsp;+\u0026thinsp;Die-punch\" fragment combination accounted for 45.0% (9/20), and 65.0% (13/20) of the medial fragments involved above the dome; 65.0% (13/20) had a fracture angle\u0026thinsp;\u0026gt;\u0026thinsp;90\u0026deg;; the Topliss classification in the coronal plane was mainly anterior split (45.0%) and Y-type fracture (25.0%).\u003c/p\u003e \u003cp\u003eVarus Type (40 cases, 20.8%)\u003c/p\u003e \u003cp\u003eFibula: 8 cases (20.0%) had no fracture, 21 cases (52.5%) had fractures above the tibiofibular syndesmosis, 10 cases (25.0%) had fractures at the level of the tibiofibular syndesmosis, and 1 case (2.5%) had fractures below the tibiofibular syndesmosis; the main fracture types were transverse (25.0%), complete comminuted (22.5%) and comminuted wedge fractures (15.0%).\u003c/p\u003e \u003cp\u003eTibia: The \"anterolateral\u0026thinsp;+\u0026thinsp;posterolateral\u0026thinsp;+\u0026thinsp;medial\u0026thinsp;+\u0026thinsp;Die-punch\" combination accounted for 32.5% (13/40), and 67.5% (27/40) of the medial fragments involved above the dome; 57.5% (23/40) had a fracture angle\u0026thinsp;\u0026lt;\u0026thinsp;90\u0026deg;; the Topliss classification in the sagittal plane was mainly simple sagittal split (40.0%).\u003c/p\u003e \u003cp\u003eValgus Type (14 cases, 7.3%)\u003c/p\u003e \u003cp\u003eFibula:8 cases (57.1%) had fractures above the tibiofibular syndesmosis, and 6 cases (42.9%) had fractures at the level of the tibiofibular syndesmosis; comminuted fractures accounted for 64.3% (9/14), including 5 cases (35.7%) of complete comminution, 2 cases (14.3%) of comminuted wedge, and 2 cases (14.3%) of multi-segment comminution.\u003c/p\u003e \u003cp\u003eTibia: The \"medial\u0026thinsp;+\u0026thinsp;anterolateral\u0026thinsp;+\u0026thinsp;posterolateral\" fragment combination accounted for 28.6% (4/14), and 64.3% (9/14) of the medial fragments involved above the dome; 57.1% (8/14) had a fracture angle\u0026thinsp;\u0026lt;\u0026thinsp;90\u0026deg;; the Topliss classification in the coronal plane was V/Y-type fracture (35.7%, 5/14).\u003c/p\u003e \u003cp\u003ePlantarflexion Type (26 cases, 13.5%)\u003c/p\u003e \u003cp\u003eFibula: 6 cases (23.1%) had no fracture, 12 cases (46.2%) had fractures above the tibiofibular syndesmosis, 5 cases (19.2%) had fractures at the level of the tibiofibular syndesmosis, and 3 cases (11.5%) had fractures below the tibiofibular syndesmosis; the main fracture types were oblique (38.5%) and comminuted wedge fractures (15.4%).\u003c/p\u003e \u003cp\u003eTibia: The \"medial\u0026thinsp;+\u0026thinsp;posterolateral\" fragment combination accounted for 26.9% (7/26), and Die-punch collapse accounted for 42.3% (11/26); 50.0% (13/26) of the medial fragments involved above the dome; 80.8% (21/26) had a fracture angle\u0026thinsp;\u0026gt;\u0026thinsp;90\u0026deg;; the Topliss classification in the coronal plane was mainly posterior split (57.7%).\u003c/p\u003e \u003cp\u003eNeutral Type (92 cases, 47.9%)\u003c/p\u003e \u003cp\u003eFibula: 38 cases (41.3%) had no fracture, 37 cases (40.2%) had fractures above the tibiofibular syndesmosis, and 17 cases (18.5%) had fractures at the level of the tibiofibular syndesmosis; comminuted fractures accounted for 30.4% (28/92), including 11 cases (12.0%) of comminuted wedge, 10 cases (10.9%) of complete comminution, and 7 cases (7.6%) of multi-segment comminution.\u003c/p\u003e \u003cp\u003eTibia: The \"anterolateral\u0026thinsp;+\u0026thinsp;posterolateral\u0026thinsp;+\u0026thinsp;medial\u0026thinsp;+\u0026thinsp;Die-punch\" combination accounted for 33.7% (31/92), and Die-punch collapse accounted for 72.8% (67/92); 77.2% (71/92) of the medial fragments involved above the dome; 48.9% (45/92) had a fracture angle\u0026thinsp;\u0026lt;\u0026thinsp;90\u0026deg;, and 51.1% (47/92) had a fracture angle\u0026thinsp;\u0026gt;\u0026thinsp;90\u0026deg;; the Topliss classification in the sagittal plane was mainly T-type (22.8%) and simple sagittal split (20.7%), while the coronal plane was mainly Y-type (29.3%).\u003c/p\u003e \u003cp\u003e3.2 Core Differences in Tibial and Fibular Fracture Morphology(Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e)\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eCore Differences in Tibial and Fibular Fracture Morphology\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGroup\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFibular Fracture Characteristics (n\u0026thinsp;=\u0026thinsp;192))\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eTibial Fracture Characteristics (n\u0026thinsp;=\u0026thinsp;192)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDorsiflexion type\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e55% (11/20) had fractures above the tibiofibular syndesmosis\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\"Medial\u0026thinsp;+\u0026thinsp;anterolateral\u0026thinsp;+\u0026thinsp;Die-punch\" combination accounted for 45% (9/20); Fracture angle\u0026thinsp;\u0026gt;\u0026thinsp;90\u0026deg; accounted for 65% (13/20); Coronal inverted Y-type accounted for 25% (5/20)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVarus type\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e25% (10/40) had fractures at the tibiofibular syndesmosis level\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\"Anterolateral\u0026thinsp;+\u0026thinsp;posterolateral\u0026thinsp;+\u0026thinsp;medial\u0026thinsp;+\u0026thinsp;Die-punch\" combination accounted for 32.5% (13/40); Sagittal simple sagittal split accounted for 40% (16/40)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eValgus type\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e57.1% (8/14) had fractures above the tibiofibular syndesmosis\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\"Medial\u0026thinsp;+\u0026thinsp;anterolateral\u0026thinsp;+\u0026thinsp;Die-punch\" combination accounted for 28.6% (4/14); Coronal V/Y-type accounted for 35.7% (5/14)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePlantarflexion type\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e46.2% (12/26) had fractures above the tibiofibular syndesmosis\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePosterolateral bone fragment injury accounted for 61.5% (16/26); Fracture angle\u0026thinsp;\u0026gt;\u0026thinsp;90\u0026deg; accounted for 80.8% (21/26)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNeutral type\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e40.2% (37/92) had fractures above the tibiofibular syndesmosis\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMulti-column comminuted fracture accounted for 33.7% (31/92); Die-punch collapse accounted for 72.8% (67/92)72.8%(67/92)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eBiological Connection Between Injury Mechanism and Fracture Morphology\u003c/p\u003e \u003cp\u003eThis study employs quantitative analysis of imaging data from 192 patients with high-energy Pilon fractures to demonstrate that the position of the ankle joint at the time of injury (injury mechanism) is a critical biomechanical factor influencing the morphology of tibial and fibular fractures. These findings align closely with the prevailing perspective on Pilon fractures, which posits that the direction of applied forces determines the orientation of fracture lines, the distribution of fracture fragments, and the extent of comminution.\u003c/p\u003e \u003cp\u003eNeutral Type Injury: High-energy axial force, as the predominant mechanism of clinical injury (47.9%), results in the talus directly impacting the dome of the distal tibia, akin to a \"pestle.\" The central column (dome area) endures the highest compressive stress, with finite element analysis indicating peak stress levels of 180\u0026ndash;200 MPa[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. This stress distribution leads to Die-punch fractures in 73% of patients. Concurrently, the radial expansion of axial force induces secondary burst fractures in surrounding regions (medial, lateral, anterior, posterior), resulting in a complex fracture morphology characterized by \"anterolateral\u0026thinsp;+\u0026thinsp;posterolateral\u0026thinsp;+\u0026thinsp;medial\u0026thinsp;+\u0026thinsp;central collapse\" (34.1%). These findings align with the conclusion of Court-Brown et al.[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], which posits that \"neutral axial force causes multi-fragment comminution.\" This study further quantifies the Die-punch collapse rate and fragment combination ratio, thereby addressing specific gaps in previous research.\u003c/p\u003e \u003cp\u003eDorsiflexion-type injury: Ankle joint dorsiflexion results in a 60% reduction in the contact area between the talus and the anterior column of the tibia [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e], thereby concentrating stress on the anterior portion of the distal tibia, specifically in the Tillaux-Chaput fragment region. This stress concentration can lead to a combined \"anterolateral\u0026thinsp;+\u0026thinsp;central column\" injury, with 45% of cases exhibiting \"medial\u0026thinsp;+\u0026thinsp;anterolateral\u0026thinsp;+\u0026thinsp;Die-punch\" injuries. Conversely, during plantarflexion, the combined effects of vertical and external rotational forces transmit axial loads along the fibula[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e], leading to fractures above the tibiofibular syndesmosis in 55.0% of patients.\u003c/p\u003e \u003cp\u003ePlantarflexion Type Injury: Plantarflexion of the ankle joint results in the talus impacting the posterior column of the tibia, specifically in the Volkmann fragment area. This action predominantly induces shear stress, leading to a fracture angle greater than 90\u0026deg; in 80.8% of patients and a posterolateral column injury rate of 61.5% (16 out of 26 cases). These findings align closely with the conclusions drawn by Wang et al[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]., who demonstrated through cadaveric specimen experiments that the stress concentration coefficient of the posterior column in the plantarflexed position is 1.8 times higher than in the neutral position. Concurrently, Lou and colleagues [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e] propose that this injury pattern is attributable to axial compression combined with rotational force, which compresses or even displaces the posterior articular surface of the tibia. This mechanism results in the posterior fragment extending to the posterior or medial malleolus, corroborating the occurrence of medial and posterolateral fracture fragments observed in 26.9% of cases in this study.\u003c/p\u003e \u003cp\u003eVarus type Injury: A varus force results in the compression of the medial edge of the talus against the medial column of the tibia, leading to the formation of a \"large medial column fragment (67.5% involving above the dome) and a simple tension fracture of the lateral column (transverse/wedge accounting for 40%).\" This pattern reflects the mechanical principle of \"medial compression and lateral tension,\" which aligns with the finite element analysis conducted by Zhang et al. [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. In pediatric varus-type Pilon fractures, particular attention should be given to the lateral ligament complex and avulsion fractures, as these have a high rate of missed diagnosis. This fracture type predominantly manifests as sagittal fractures (40% simple sagittal split) and evolves into an inverted V/T configuration with increased force [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eValgus type Injury:A valgus force induces an outward and upward displacement of the talus, leading to complete comminution and a 28.6% collapse of the lateral distal tibia. Concurrently, the transmission of force results in fibular fractures predominantly occurring above the tibiofibular syndesmosis, corroborating the findings of Zhang et al[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. through 3D CT reconstruction. This study, however, provides a more detailed characterization: 57.1% of fibular fractures in the valgus group are situated above the tibiofibular syndesmosis, and 64.3% exhibit comminution. This suggests that under valgus force, the fibula is subjected not only to axial loading but also to shear forces in the abduction direction, resulting in more complex fracture morphologies. Additionally, the valgus type is frequently associated with coronal fractures, which progressively evolve from simple coronal fractures to V/Y types as the force increases, with 35.7% exhibiting the coronal V/Y type [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eCorrespondence and Supplement to Existing Classification Systems\u003c/p\u003e \u003cp\u003eRuedi-Allgower classification[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]: As the most established classification system for Pilon fractures, it primarily addresses the extent of comminution and displacement associated with these fractures, exerting a widespread and significant influence. However, its application is constrained by technological limitations, as it relies solely on X-ray imaging to assess fracture displacement and comminution. This study employs computed tomography (CT) and three-dimensional imaging technologies to enhance the evaluative scope of the classification system by incorporating quantitative metrics such as fragment configuration and fracture line analysis.\u003c/p\u003e \u003cp\u003eAO classification: In 1987, M\u0026uuml;ller and colleagues [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e] endeavored to develop a comprehensive classification system for long bone fractures, known as the AO classification. This system categorizes Pilon fractures into three types\u0026mdash;A, B, and C\u0026mdash;based on the involvement of the articular surface. While this classification effectively describes the fracture morphology of Pilon fractures, it exhibits a weak correlation between the three types and fails to adequately reflect the severity of the fractures [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. Additionally, the classification does not account for injury mechanisms and merely describes the comminution of the articular surface. This study addresses these limitations by correlating fracture morphology with different injury mechanisms, thereby providing a more comprehensive understanding.\u003c/p\u003e \u003cp\u003eFive-column classification: Recently, In recent years, Liu et al. [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e] introduced a novel classification system for Pilon fracture morphology utilizing finite element analysis. This system categorizes Pilon fractures into five distinct columns based on three primary injury mechanisms, thereby delineating fracture morphology through columnar division. While the initial classification establishes a correlation between injury mechanisms and morphological characteristics, the present study expands upon this framework by examining five injury mechanisms. It integrates additional parameters, such as fracture lines and angles, to enhance the granularity and precision of the classification system.\u003c/p\u003e \u003cp\u003eAnterior/posterior Pilon fracture subtypes: Cao Junmin et al. [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e] characterized the \"anterior Pilon fracture\" as primarily involving an \"anterior column split with central collapse.\" In this study, 80% of dorsiflexion-type fractures exhibited this feature. The authors further quantified the occurrence of the \"anterolateral and central column\" combination at 45%, suggesting that the presence of an anterolateral fragment, Die-punch collapse, and medial fragment extending above the dome on CT imaging can serve as diagnostic criteria for anterior Pilon fractures. Conversely, the study identified that 61.5% of plantarflexion-type injuries involved the posterolateral column, aligning with the \"posterior Pilon fracture\" described by Lou et al. [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. This finding is complemented by a prognostic indicator, whereby a fracture angle greater than 90\u0026deg; is associated with a 2.3-fold increased risk of postoperative nonunion of the posterior malleolus [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eCT classification:The classification system introduced by Leonetti et al. [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e], which utilizes CT scans, aims to detail the extent of articular surface involvement by fractures, the displacement and number of joint fragments, the positioning of primary fracture lines, and the areas of comminution. While this system provides a thorough representation of the comminution of the distal tibial articular surface, it lacks consideration of the injury mechanism and fails to elucidate the concept of fracture fragment combinations. The present study successfully addresses these deficiencies.\u003c/p\u003e \u003cp\u003eClinical Application Value\u003c/p\u003e \u003cp\u003eOptimization of preoperative evaluation: The identification of characteristic fracture fragments through three-dimensional CT reconstruction can facilitate the retrospective inference of injury mechanisms. For instance, a \"posterolateral fragment with a fracture angle greater than 90\u0026deg;\" is indicative of a plantarflexion-type injury, necessitating MRI evaluation of the posterior ankle fracture prior to surgical intervention. Conversely, the presence of a \"lateral comminuted fragment with a fracture located above the tibiofibular syndesmosis\" suggests a valgus-type injury, warranting careful assessment for potential diastasis of the tibiofibular syndesmosis[\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. Additionally, the combination of \"posteromedial and anterolateral fragments\" necessitates evaluation of the risk for postoperative entrapment of the tibialis posterior tendon, as this could adversely impact postoperative functional outcomes [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eStudy Limitations\u003c/p\u003e \u003cp\u003eRetrospective study bias:This study exclusively examines fracture morphology and does not include a longitudinal assessment of postoperative joint function outcomes, such as the American Orthopaedic Foot \u0026amp; Ankle Society (AOFAS) score, or complications, including traumatic arthritis and nonunion. Future studies with a minimum follow-up period of two years are necessary to elucidate the comprehensive correlation chain of \"mechanism-morphology-prognosis.\"\u003c/p\u003e \u003cp\u003eLack of biomechanical verification: The correlation between \"stress-fracture morphology\" proposed in this study, derived from clinical observations, has yet to be validated through dynamic mechanical loading experiments using cadaveric specimens[\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e] or 3D-printed models. Future research should incorporate the MTS mechanical testing system[\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e] to simulate force loading at various positions, thereby quantifying the stress distribution and determining the fracture threshold for each column.\u003c/p\u003e \u003cp\u003eLack of long-term prognosis data: This study is limited to the analysis of fracture morphology and does not include longitudinal assessment of postoperative joint function, such as the American Orthopaedic Foot \u0026amp; Ankle Society (AOFAS) score, or complications, such as traumatic arthritis and nonunion, in patients. Future studies with a follow-up period of at least two years are required to elucidate the comprehensive correlation chain encompassing \"mechanism, morphology, and prognosis.\"\u003c/p\u003e \u003cp\u003eFormulation of individualized surgical strategies: Based on the strategic selection of the approach and fixation plan, the following methods are employed:(1)Plantarflexion type:A modified posteromedial approach, involving an incision medial to the posterior tibial artery, was employed to expose the flexor hallucis longus tendon. This technique allowed for complete visualization of the Volkmann fragment and the medial fragment, facilitating clear observation of the fracture line orientation, the number of fragments, and the degree of displacement[\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e, \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. Direct visualization during reduction was utilized to minimize the risk of traumatic arthritis[\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e].༈2༉Dorsiflexion type: Complex anterior Pilon fractures are associated with a high complication rate when utilizing combined anterolateral and anteromedial surgical approaches. The choice of surgical technique is determined by the presence of \"anterior/anterolateral fragments (Tillaux-Chaput)\" or \"posterolateral fragments (Volkmann).\" The efficacy and safety of this strategy are assessed, demonstrating that anterolateral fragments (Tillaux-Chaput) can be accurately fixed[\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e].༈3༉Valgus Type: In cases of comminuted fibular fractures accompanied by lateral tibial collapse[\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e], lateral plate fixation has been shown to yield optimal outcomes [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]. The anterolateral or Bohler approach may be employed to achieve comprehensive exposure of the fibular fracture, the lateral tibial articular surface, the Tillaux-Chaput fragments, and the tibiofibular syndesmosis. However, it is imperative to exercise caution to protect the superficial peroneal nerve and the perforators of the peroneal artery [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]. In instances where the condition of the soft tissue is suboptimal, a staged treatment protocol should be implemented. This involves maintaining alignment with an external fixator during the initial stage, followed by reduction through double lateral and anterolateral incisions in the subsequent stage, thereby minimizing the risk of soft tissue necrosis.༈4༉Neutral Type: The sequence of \"first reducing the peripheral fragment framework, then prying and reducing the central collapse[\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]\", combined with porous tantalum metal bone grafting to support the central column, the reduction loss rate is only 3.2% (significantly lower than 15.6% of autologous bone grafting); ༈5༉Varus Type: Varus stress contributes to the development of an ankle varus deformity, while the application of a medial plate can inhibit the progression of this deformity[\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e, \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]. Utilizing an anteromedial approach to the distal tibia facilitates enhanced exposure of the central tibial region and the medial articular surface. Implementing early rigid internal fixation of the medial fragment[\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e, \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e], combined with partial weight-bearing to deliver appropriate stress stimulation, can significantly enhance patient prognosis and minimize postoperative complications.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eA significant and predictable correlation exists between the fracture morphology of the distal tibia in high-energy Pilon fractures and the specific position of the ankle joint at the time of injury, which is determined by the injury mechanism. The five primary injury mechanisms\u0026mdash;dorsiflexion, varus, valgus, plantarflexion, and neutral positions\u0026mdash;result in distinct fracture types, fragment distribution patterns, and fracture line morphologies. This correspondence between mechanism and morphology profoundly reflects the biomechanical response of various regions of the distal tibia under specific loading conditions. The findings of this study enhance the theoretical foundation for understanding the morphological complexity of Pilon fractures in relation to injury mechanisms and provide objective evidence for clinicians to predict fracture characteristics. This understanding facilitates the optimization of preoperative planning and surgical strategies through detailed imaging analysis. Ultimately, the goal is to achieve more precise fracture reduction and stable fixation, thereby improving the functional prognosis for patients. Future research could incorporate more sophisticated finite element mechanical analysis or cadaveric mechanical analysis to enhance the comprehensive understanding of injury mechanisms.\u003c/p\u003e "},{"header":"Declarations","content":"\u003cp\u003eEthical Approval and Informed Consent\u003c/p\u003e\n\u003cp\u003eThis study received ethical approval from the Ethics Committee of The Second People\u0026apos;s Hospital of Lianyungang, under approval number AF/SC-08/01.0. Informed consent was obtained from all participants, who signed the necessary consent forms. All research procedures involving human participants adhere to the ethical standards set forth by the institutional research committee and are in accordance with the 1964 Helsinki Declaration and its subsequent amendments or equivalent ethical guidelines.\u003c/p\u003e\n\u003cp\u003eFunding\u003c/p\u003e\n\u003cp\u003eThis research was funded by the Scientific Research Development Fund of Kangda College, Nanjing Medical University, under project number KD2024KYJJ050.\u003c/p\u003e\n\u003cp\u003eAuthor Contribution\u003c/p\u003e\n\u003cp\u003eH.Q .Ccontributed to formal analysis, funding acquisition, software development, and the initial drafting of the manuscript. C. G was responsible for formal analysis and investigation. J.W.H handled data curation, software development, and funding acquisition. A.Z. S was involved in methodology development and project administration. K.F. S contributed to methodology development, project administration, and the review and editing of the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of Interest Statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors of this study confirm that there are no identifiable financial conflicts of interest, personal relationships, or other potential influencing factors that could interfere with the objectivity of the research, the presentation of results, or the derivation of conclusions. All authors take full responsibility for the authenticity of the research data, analysis results, and the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthical Statement\u003c/strong\u003e\u003c/p\u003e\n\u003col start=\"1\" type=\"1\"\u003e\n \u003cli\u003eThis study has been approved by the Ethics Committee of The Second People\u0026apos;s Hospital of Lianyungang, with the approval number AF/SC-08/01.0.\u003c/li\u003e\n \u003cli\u003eAll participants in this study have signed written informed consent forms, fully understanding the purpose, procedures, and potential risks of the research.\u003c/li\u003e\n \u003cli\u003eAll experimental procedures, data collection, and analysis processes of this study strictly adhere to the 1964 Helsinki Declaration and its subsequent amendments or equivalent ethical guidelines, complying with the ethical standards for human research.\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eWajsfisz A, Makridis KG, Naji O, Hirsh C, Boisrenoult P, Beaufils P (2014) An anterior ankle arthroscopic technique for retrograde osteochondral autograft transplantation of posteromedial and central talar dome cartilage defects. Knee Surg Sports Traumatol Arthrosc 22:1298\u0026ndash;1303\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMauffrey C, Vasario G, Battiston B, Lewis C, Beazley J, Seligson D (2011) Tibial pilon fractures: a review of incidence, diagnosis, treatment, and complications. Acta Orthop Belg 77:432\u0026ndash;440\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBone LB (1987) Fractures of the tibial plafond. The pilon fracture. Orthop Clin North Am 18:95\u0026ndash;104\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKellam JF, Waddell JP (1979) Fractures of the distal tibial metaphysis with intra-articular extension\u0026ndash;the distal tibial explosion fracture. J Trauma 19:593\u0026ndash;601\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eR\u0026uuml;edi T (1973) Fractures of the lower end of the tibia into the ankle joint: results 9 years after open reduction and internal fixation. 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Clin Orthop Relat Res :105\u0026ndash;110\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVu C, Gendelberg D (2020) Classifications in Brief: AO Thoracolumbar Classification System. Clin Orthop Relat Res 478:434\u0026ndash;440\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eM\u0026uuml;ller ME, Nazarian S (1981) [Classification of fractures of the femur and its use in the A.O. index (author's transl)]. Rev Chir Orthop Reparatrice Appar Mot 67:297\u0026ndash;309\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTopliss CJ, Jackson M, Atkins RM (2005) Anatomy of pilon fractures of the distal tibia. J Bone Joint Surg Br 87:692\u0026ndash;697\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDas A, Malhotra R, Srivastava A, Tandon A, Jain AK, Aggarwal AN, Rajnish RK (2023) Assessment of inter and intra-observer variation of Leonetti and Tigani CT bases classification of tibial pilon fractures. Int J Burns Trauma 13:51\u0026ndash;57\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePalma J, Villa A, Mery P, Abarca M, Mora A, Pe\u0026ntilde;a A, Urrutia J, Filippi J (2020) A New Classification System for Pilon Fractures Based on CT Scan: An Independent Interobserver and Intraobserver Agreement Evaluation. J Am Acad Orthop Surg 28:208\u0026ndash;213\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiu J, Piao C, Cui G, Sun H, Li Z (2025) Fracture Line Morphology and a Novel Classification of Pilon Fractures. Orthop Surg 17:540\u0026ndash;550\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJia B, Zhang Y, Li ZL, Cao GQ, Liu YX (2011) [Classification of pilon fractures by computed tomography and its guide to clinical treatment]. Zhongguo Gu Shang 24:470\u0026ndash;473\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang GM, Ruan ZY, Yi LL, Yin HL, Pan FG (2018) Morphological analysis and three-dimensional finite element analysis of injury mechanism of posterior malleolus fracture variant of Pilon. Zhonghua Shi Yan Wai Ke Za Zhi 35:2035\u0026ndash;2038\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhu G, Cao S, Zhu J, Yuan C, Wang Z, Huang J, Ma X, Wang X (2024) Combined vertical and external rotational force in plantarflexion position produces posterior pilon fracture: A preliminary cadaveric study. Foot Ankle Surg 30:394\u0026ndash;399\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang J, Wang X, Xie L, Zheng W, Chen H, Cai L (2020) Comparison of radiographs and CT features between posterior Pilon fracture and posterior malleolus fracture: a retrospective cohort study. Br J Radiol 93:20191030\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOvadia DN, Beals RK (1986) Fractures of the tibial plafond. J Bone Joint Surg Am 68:543\u0026ndash;551\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSwiontkowski MF, Sands AK, Agel J, Diab M, Schwappach JR, Kreder HJ (1997) Interobserver variation in the AO/OTA fracture classification system for pilon fractures: is there a problem? J Orthop Trauma 11:467\u0026ndash;470\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCao JM, Wang Q, Wang Y, Chen J, Jiang HP, Zhang PJ (2023) Imaging characteristics and surgical efficacy analysis of anterior Pilon fractures. Shi Yong Gu Ke Za Zhi 29:747\u0026ndash;752\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eUrrutia T, Faundez J, Vidal C, Palma J, Filippi J (2025) Visualizing access in pilon fractures: A comparative study of eight approaches. Foot Ankle Surg 31:539\u0026ndash;546\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLeonetti D, Tigani D (2017) Pilon fractures: A new classification system based on CT-scan. Injury 48:2311\u0026ndash;2317\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYeung TW, Chan CY, Chan WC, Yeung YN, Yuen MK (2015) Can pre-operative axial CT imaging predict syndesmosis instability in patients sustaining ankle fractures? Seven years' experience in a tertiary trauma center. Skeletal Radiol 44:823\u0026ndash;829\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLabrum JTt, Gallagher B, Boyce RH (2023) Injury Pattern Recognition and Surgical Technique of Pilon Fracture Reduction With Posterior Tibial Tendon Incarceration. J Orthop Trauma 37:e227\u0026ndash;e231\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSwitaj PJ, Weatherford B, Fuchs D, Rosenthal B, Pang E, Kadakia AR (2014) Evaluation of posterior malleolar fractures and the posterior pilon variant in operatively treated ankle fractures. Foot Ankle Int 35:886\u0026ndash;895\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBacon S, Smith WR, Morgan SJ, Hasenboehler E, Philips G, Williams A, Ziran BH, Stahel PF (2008) A retrospective analysis of comminuted intra-articular fractures of the tibial plafond: Open reduction and internal fixation versus external Ilizarov fixation. Injury 39:196\u0026ndash;202\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTenenbaum S, Shazar N, Bruck N, Bariteau J (2017) Posterior Malleolus Fractures. Orthop Clin North Am 48:81\u0026ndash;89\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDi Giorgio L, Touloupakis G, Theodorakis E, Sodano L (2013) A two-choice strategy through a medial tibial approach for the treatment of pilon fractures with posterior or anterior fragmentation. Chin J Traumatol 16:272\u0026ndash;276\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSirkin MS (2007) Plating of tibial pilon fractures. Am J Orthop (Belle Mead NJ) 36:13\u0026ndash;17\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFemino JE, Vaseenon T (2009) The direct lateral approach to the distal tibia and fibula: a single incision technique for distal tibial and pilon fractures. Iowa Orthop J 29:143\u0026ndash;148\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHaraguchi N, Toga H, Shiba N, Kato F (2007) Avulsion fracture of the lateral ankle ligament complex in severe inversion injury: incidence and clinical outcome. Am J Sports Med 35:1144\u0026ndash;1152\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHelfet DL, Haas NP, Schatzker J, Matter P, Moser R, Hanson B (2003) AO philosophy and principles of fracture management-its evolution and evaluation. J Bone Joint Surg Am 85:1156\u0026ndash;1160\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eScolaro J, Ahn J (2011) Pilon fractures. Clin Orthop Relat Res 469:621\u0026ndash;623\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMiller TL, Kaeding CC, Rodeo SA (2020) Emerging Options for Biologic Enhancement of Stress Fracture Healing in Athletes. J Am Acad Orthop Surg 28:1\u0026ndash;9\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHaller JM, Holt D, Rothberg DL, Kubiak EN, Higgins TF (2016) Does Early versus Delayed Spanning External Fixation Impact Complication Rates for High-energy Tibial Plateau and Plafond Fractures? Clin Orthop Relat Res 474:1436\u0026ndash;1444\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOtt N, Harbrecht A, Hackl M, Leschinger T, Knifka J, M\u0026uuml;ller LP, Wegmann K (2021) Inducing pilon fractures in human cadaveric specimens depending on the injury mechanism: a fracture simulation. Arch Orthop Trauma Surg 141:837\u0026ndash;844\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRamlee MH, Sulong MA, Garcia-Nieto E, Penaranda DA, Felip AR, Kadir MRA (2018) Biomechanical features of six design of the delta external fixator for treating Pilon fracture: a finite element study. Med Biol Eng Comput 56:1925\u0026ndash;1938\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Pilon fracture, Injury mechanism, Fracture morphology, Imaging characteristics, Biomechanics, Precise diagnosis and treatment","lastPublishedDoi":"10.21203/rs.3.rs-8120358/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8120358/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThis study investigates the link between injury mechanisms and the morphology of high-energy Pilon fractures to support accurate clinical diagnosis and treatment. It includes 192 patients from Lianyungang Second People's Hospital (2010\u0026ndash;2024), categorized into five groups based on trauma history and imaging: dorsiflexion, varus, valgus, plantarflexion, and neutral. Two experienced orthopedic surgeons independently assessed X-rays, CT scans, and 3D reconstructions, noting fibular fracture details, tibial fragment distribution, fracture angle, and Topliss classification. Statistical analysis was done using SPSS 25.0, with chi-square or Fisher's exact tests (P\u0026thinsp;\u0026lt;\u0026thinsp;0.05 for significance). The study identified distinct fracture patterns based on injury mechanisms (P\u0026thinsp;\u0026lt;\u0026thinsp;0.05): Dorsiflexion injuries often had \"medial\u0026thinsp;+\u0026thinsp;anterolateral\u0026thinsp;+\u0026thinsp;Die-punch\" fragments (45%), fracture angles\u0026thinsp;\u0026gt;\u0026thinsp;90\u0026deg; (65%), and coronal Y-type fractures (25%). Varus injuries typically presented \"anterolateral\u0026thinsp;+\u0026thinsp;posterolateral\u0026thinsp;+\u0026thinsp;medial\u0026thinsp;+\u0026thinsp;Die-punch\" fragments (32.5%) and sagittal split fractures (40%). Valgus injuries were associated with comminuted fibular fractures (64.3%) and tibial coronal V/Y-type fractures (35.7%). Plantarflexion injuries frequently involved posterolateral fragments (61.5%) and fracture angles\u0026thinsp;\u0026gt;\u0026thinsp;90\u0026deg; (80.8%). Neutral injuries were marked by complex comminuted fractures, with 33.7% showing Die-punch collapse. This study establishes a significant correlation between the morphology of high-energy Pilon fractures and their injury mechanisms, suggesting that preoperative mechanism classification can enhance surgical strategies and minimize complications.\u003c/p\u003e","manuscriptTitle":"Research on the Morphology and Injury Mechanism of Pilon Fractures","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-12-16 09:03:36","doi":"10.21203/rs.3.rs-8120358/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"2c499ab7-abe2-4b4e-bbd5-632573cdde44","owner":[],"postedDate":"December 16th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-12-16T09:03:36+00:00","versionOfRecord":[],"versionCreatedAt":"2025-12-16 09:03:36","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8120358","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8120358","identity":"rs-8120358","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}