The importance of Böhler’s angle in calcaneus geometry: A finite element model study

Abstract

Objectives: Calcaneal fractures are the most common tarsal fractures following a foot-ankle trauma. The Böhler’s angle is an important measurable angle before, during, and after surgery. In this study, we aimed to investigate correlation between Böhler’s angle, calcaneal strength, and subtalar joint stress using a finite element analysis (FEA). Patients and methods: Between January 2016 and December 2016, computed tomography (CT) scans were used with MIMICS® software for FEA. The ankle and foot of a 23-year-old male person with a height of 180 cm and weighing 80 kg was modeled as reference. Raw coronal CT images were obtained in Digital Imaging and Communications in Medicine format with the resolution of 512X512 pixels and 0.3-mm slice intervals in 135 kV. The structures including tibia, fibula and 26 other bones (talus, calcaneus, cuboid, navicular, three cuneiforms, five metatarsals, and 14 components of phalanges), cartilage and ligamentous tissues were modeled to form ankle joint. After determining Böhler’s angle as 35 degrees for the reference model, a fracture line was created on calcaneus. Calcaneus was remodeled with the Böhler’s angle of 45, 40, 30, 25, 20, 10, and 0 degrees respectively. All models were transferred to ANSYS software for FEA and the loads on the lower extremities with normal posture were applied on models. Results: Analysis of all models based in the reference model revealed that maximum tension values on calcaneus increased, while the Böhler’s angle decreased, indicating a statistically significant difference. The decreased Böhler’s angle indicated statistically significantly higher maximum tension values (p=0.04). Action force in subtalar joint was evaluated by comparing with the forces in reference model. The increased Böhler’s angle was found to be associated with statistically significantly decreased amount of load on subtalar joint. The decreased Böhler’s angle was related to the statistically significantly increased amount of load on subtalar joint. Conclusion: Our study results suggest that decreased Böhler’s angle increases the possibility of subtalar arthrosis, although overcorrection of the Böhler’s angle seems not to increase the risk of subtalar arthrosis.

Percutaneous and Arthroscopically Assisted Osteosynthesis for Calcaneal Fractures with Displacement of Different Calcaneal Talar Facet: A Retrospective Study

“…This may result in calcaneus collapse, as evidenced by the decrease of the Bohler angle and calcaneal height in the present study. The decreased Bohler angle was followed by the signi cantly increased pressure on subtalar joint [34]. The Bohler angle of Type III decreased more obviously, leading to more increased pressure.…”

Hollow screw fixation of type II avulsion fractures of the calcaneal tuberosity using the finite element analysis

“…Second, the mechanical influence of the tendinous tissues surrounding the calcaneus, such as the Achilles tendon, metatarsal fascia, ligaments, and the toe flexor tendon, on the heel bone is yet to be studied in a large number of biomechanical studies. [ 19 ]…”

In Vivo Foot and Ankle Kinematics During Activities Measured by Using a Dual Fluoroscopic Imaging System: A Narrative Review

“…Furthermore, this system cannot analyse the movement of a single bone nor obtain the 6DOF motion of joints. Although computer simulation methods, for example, the finite element model ( Gültekin et al, 2021 ), can simulate the 6DOF movement of an independent joint with computer programming, it cannot measure in vivo joint kinematics, let alone obtain the real movement of the joints in functional activities, such as walking, jumping and running. Human cadaver studies involving the implantation of steel beads or pressure sensors into the human body can also quantify the movement in a single bone but are invasive and raise ethical concerns.…”