Objective To study the general distribution of fracture lines in distal radius fractures (DRFs). Methods Computed tomography scans from 50 patients with DRFs were included in this study. The DICOM data of all patients were analyzed using Mimics 20.0 software, and the bone blocks were marked with different colors after the surrounding related bones were removed. After reduction of the fracture, 3-matic software was used to plot 50 fracture lines on the same standardized bone structure of the distal radius. Finally, a heat map was developed based on the frequency of the fracture lines. Results Although the fracture lines varied widely in DRFs, most fracture lines were regularly distributed. In the metaphyseal region of the distal radius, the width of the ring was 4.52 mm, and the ring was located in the region of primary epiphyseal cartilage development below the watershed. Fractures below the annular band were occasional. The distribution of volar fracture lines above the annular band was significantly less than that of dorsal fracture lines, which was more concentrated in the area around the Lister tubercle and more involved in the distal radioulnar joint. Conclusion The fracture lines were regularly distributed in the distal radius with a ring-shaped high-incidence zone.

Background By establishing a three-dimensional finite element model of supination and external rotation ankle injury, the stress characteristics of the posterior ankle joint surface can be obtained, and complete analysis of the corresponding stress on the lateral ankle can be conducted.Methods Thin-layer computed tomography (CT) images of normal ankle joints in the supination and external rotation nonweight-bearing states were selected, a three-dimensional data model of each ankle joint, including the ligament, was established, and whether different stages of injury coexisted with lateral ankle fracture was analysed by the finite element method. A load was applied to examine different ankle joint stress values and pressure distributions on the surface of the posterior ankle joint.Results When a load was applied, the maximum stress was located at the point of attachment of the anterior tibiofibular ligament to the tibia. When the anterior tibiofibular ligament was removed and the lateral malleolus was intact, the maximum stress (271.2 MPa) was located at the attachment point of the posterior tibiofibular ligament to the tibia, and the maximum pressure of the posterior ankle joint surface was 2.626 MPa. When a lateral malleolar fracture was present and the same load was applied, the maximum stress (82 MPa) was located on the fibular fracture surface, and the maximum pressure of the posterior ankle joint surface was 7.787 MPa. The posterior tibiofibular ligament was then removed completely from the lateral malleolus, upon which the maximum stress (132.7 MPa) was located at the point of attachment of the posterior tibiofibular ligament to the fibula and the maximum pressure of the posterior ankle joint surface was 4.505 MPa. When a lateral malleolar fracture was present, the maximum stress (82.72 MPa) was located on the fibular fracture surface, and the maximum pressure of the posterior ankle joint surface was 8.022 MPa.Conclusion This study shows that reconstruction of the lateral malleolus in supination-external rotation ankle injury significantly affects the stress distribution at the posterior malleolar joint surface. When reconstruction of the lateral malleolus is complete, the pressure distribution of the posterior malleolar joint surface can be significantly reduced. The disappearance of pressure concentration helps reduce the stresses associated with posterior ankle fracture. At this time, the rotational stress imposed by posterior ankle fracture is significantly higher than the vertical stress; the former should be the focus of clinician attention to ensure optimal healing.

BackgroundBy establishing a three-dimensional finite element model of supination and external rotation ankle injury, the stress characteristics of the posterior ankle joint surface can be obtained, and complete analysis of the corresponding stress on the lateral ankle can be examined. MethodsThin-layer computed tomography (CT) images of normal ankle joints in the supination and external rotation non-weight-bearing states were selected, a three-dimensional data model of each ankle joint, including the ligament, was established, and whether different degrees of injury were coexistent with lateral ankle fracture was analysed by the finite element method. A load was applied to examine different ankle joint stress values and pressure distributions on the surface of the posterior ankle joint. ResultsWhen a load was applied, the maximum stress was located at the point of attachment of the anterior tibiofibular ligament to the tibia. When the anterior tibiofibular ligament was removed and the lateral malleolus was intact, the maximum stress (271.2 MPa) was located at the attachment point of the posterior tibiofibular ligament to the tibia, and the maximum pressure of the posterior ankle joint surface was 2.626 MPa. When a lateral malleolus fracture was present and the same load was applied, the maximum stress (82 MPa) was located on the fibular fracture surface, and the maximum pressure of the posterior ankle joint surface was 7.787 MPa. The posterior tibiofibular ligament was then removed completely from the lateral malleolus, and the maximum stress (132.7 MPa) was located at the point of attachment of the posterior tibiofibular ligament to the fibula, and the maximum pressure of the posterior ankle joint surface was 4.505 MPa. When a lateral malleolar fracture was present, the maximum stress (82.72 MPa) was located on the fibular fracture surface, and the maximum pressure of the posterior ankle joint surface was 8.022 MPa. ConclusionThis study shows that reconstruction of the lateral malleolus in supination-external rotation ankle injury significantly affects the stress distribution at the posterior malleolar joint surface. When reconstruction of the lateral malleolus is complete, the pressure distribution of the posterior malleolar joint surface can be significantly reduced. The results highlight the significance of reconstruction of posterior malleolar fractures and posterior tibiofibular ligament stability.