Three-dimensional mapping study of pure transverse acetabular fractures

Li et al. Journal of Orthopaedic Surgery and Research https://doi.org/10.1186/s13018-022-03148-8 (2022) 17:264 Open Access RESEARCH Three‑dimensional mapping study of pure transverse acetabular fractures Junran Li1,2†, Jingxiu Zhai3†, Yingchao Yin1,2, Siyu Tian1,2, Zhongzheng Wang1,2, Ligeng Li3, Zhiyong Hou1,2,4* and Yingze Zhang1,2,4 Abstract Background: To describe and analyze the morphological characteristics, location and frequency of pure transverse acetabular fracture lines through fracture mapping and quantitative measurements. Methods: Transverse fractures were retrospectively reviewed and analyzed. All computed tomography (CT) data were used for reconstruction and manual reduction. The reductive fracture fragments were graphically overlaid onto a three-dimensional (3D) right hemipelvis template. Then, the fracture lines were accurately depicted onto the surface of the 3D template. The fracture lines were overlapped onto the model to create the 3D fracture map and heatmap. All cases were subdivided into infratectal (62-B1.1), juxtatectal (62-B1.2), and transtectal (62-B1.3) types based on the AO Foundation/Orthopedic Trauma Association (AO/OTA) classification. Some anatomic parameters of the transverse fractures were also analyzed in these 3 groups. Results: Our study included forty-nine transverse fractures from 32 male and 17 female patients (mean age, 42 years; range 21–74 years) and included 19 type 62-B1.1, 17 type 62-B1.2, and 13 type 62-B1.3 fractures. The average anterior rim fracture angle was 70.0° (± 11.6°), and the posterior rim fracture angle was 92.4° (± 28.5°). The anterior rim fracture angles in 40 cases (40/49, 81.6%) fell within a wide range between 63° and 80°. On the heatmap, the hot zones were located on the highest position of the cotyloid fossa and the narrowed region, and the cold zone was on the inferior third of the articular surface. For type 62-B1.3 fractures, the hot zone was located on the posterior of the acetabular dome. There were no significant differences in anterior rim fracture angle and anterior height among the three patterns (P = 0.071, P = 0.072). Post hoc tests of the posterior rim fracture angle and the posterior height revealed significant differences among fracture subtypes (P < 0.01). The posterior intra-articular fracture line was significantly longer than the anterior intra-articular fracture line in type 62-B1.1 and type 62-B1.2 fractures (P < 0.01). Conclusion: The fracture lines of transverse fractures through the anterior rim were concentrated on the narrowed zone, and the posterior fracture lines were diffusely distributed. The intra-articular fracture line distribution was focused on the superior and middle thirds of the joint surface. The recurrent fracture lines involving the weight-bearing dome mainly converged on the posterior region of the roof. Keywords: Transverse fracture, Fracture mapping, Heatmap, Computed tomography, AO/OTA 62-B1 † Junran Li and Jingxiu Zhai contributed equally to this work and should be considered co-first authors *Correspondence: 1 Department of Orthopaedic Surgery, Third Hospital of Hebei Medical University, Shijiazhuang, Hebei Province, China Full list of author information is available at the end of the article Introduction Pure transverse acetabular fracture is defined as an elementary fracture type in the Judet–Letournel classification because of the simple geometric form of its fracture line [1, 2]. However, in clinical practice, surgical treatment may be difficult considering that lesions of this type involve both anterior and posterior © The Author(s) 2022. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data. Li et al. Journal of Orthopaedic Surgery and Research (2022) 17:264 columns [3]. Moreover, most patients have concomitant injuries of the acetabulum and pelvic ring [4]. These conditions result in large challenges in the surgical treatment of transverse acetabular fractures [5]. To date, the incidence of postoperative complications still remains high [6]. The Judet–Letournel, Marvin Tile, AO Foundation/Orthopedic Trauma Association (AO/OTA), and 3-column classification systems for acetabular fractures have been used to describe fracture patterns and provide treatment protocols [7–10]. The traditional Judet–Letournel and latest AO/OTA classifications are common clinical classification methods that have categorized pure transverse acetabular fractures into infratectal (62-B1.1), juxtatectal (62-B1.2), and transtectal (62-B1.3) types according to the level at which the fracture ruptured the acetabulum [9, 10]. These three kinds of subtypes also indicate whether the roof was involved, which could help in surgical planning and prognosis prediction. Although orthopedists have devoted considerable attention to the fracture line locations on the articular surface, it might be quite difficult to grasp preoperatively whether the acetabular dome was broken by using conventional radiographic imaging. Computed tomography (CT) is appropriate for obtaining an accurate assessment of acetabular fractures; even so, the configuration of the fracture line may still be unclear visually. In addition, the shapes of the transverse fracture lines can be relatively diverse. However, the above-mentioned factors are essential for making a preoperative plan and achieving an excellent clinical outcome [11]. The fracture mapping technique created by Armitage et al. based on three-dimensional (3D) CT has been widely utilized to elucidate the patterns of fracture lines, especially in irregular bone and intra-articular fractures [12–14]. With increasing concern over precise treatment and the application of various medical image postprocessing software, fracture mapping has been increasingly more common in orthopedic fields. However, to the best of our knowledge, this approach has rarely been used to analyze the distribution of acetabular fracture lines, such as models of transverse fractures. (...truncated)