Abstract
ObjectiveArthroscopic ankle arthrodesis (AAA) is a standard surgical method for the treatment of advanced traumatic ankle arthritis and has become more popular due to its advantages. To fix the tibiotalar joint, the use of three percutaneous screws is considered to have better mechanical stability than the use of two screws. However, it is sometimes difficult to insert three screws because they might block each other due to the small area of the tibiotalar joint surface and the large diameter of the screws; few articles illustrate how to insert three screws without the screws disturbing each other. The purpose of this study is to explore possible screw configurations of tripod fixation in arthroscopic ankle arthrodesis that avoid the collision of screws and yield better biomechanical performance.MethodsWe used the finite element method to examine the impact of different screw positions and orientations on the biomechanical characteristics of a three-dimensional (3D) ankle model. Maximum and average micromotion, pressure on the articular surface, and von Mises stress values of the tibia and the talus were used to evaluate the initial stability of the ankle.ResultsFive kinds of three-screw configurations were identified, and finite element analysis results suggested that configurations with the posteromedial home-run screw presented lower micromotion (maximum, 17.96 ± 7.49 μm versus 22.52 ± 12.8 μm; mean, 4.88 ± 1.89 μm versus 5.19 ± 1.92 μm) (especially configuration 3) and better screw distributions on the articular surface than those with the posterolateral home-run screw.ConclusionScrew configurations with the posteromedial home-run screw avoid collision and are more biomechanically stable than those with the posterolateral home-run screw. Thus, inserting the home-run screw through the posteromedial approach is recommended for clinical practice.
Highlights
Ankle arthrodesis (AA) is the standard surgical method for the treatment of advanced traumatic ankle arthritis [1]
Five kinds of three-screw configurations were identified, and finite element analysis results suggested that configurations with the posteromedial home-run screw presented lower micromotion and better screw distributions on the articular surface than those with the posterolateral home-run screw
Inserting the home-run screw through the posteromedial approach is recommended for clinical practice
Summary
Ankle arthrodesis (AA) is the standard surgical method for the treatment of advanced traumatic ankle arthritis [1]. It can relieve pain and help patients restore normal walking through the fusion of the tibiotalar joint. AA can be grouped into open surgery, arthroscopic ankle arthrodesis (AAA), and external fixation fusion. A recent systematic review found that AAA has higher clinical scores, fewer complications, shorter hospital stays, and less bleeding than open ankle fusion, while the overall fusion and reoperation rates of these methods are similar [5]. Two or three cannulated compression screws will be inserted percutaneously to fix the tibiotalar joint [6]. Goetzmann et al [10] retrospectively analyzed 111 AAA cases and found that the fusion rate of three screws was higher than that of two screws, and the time required for fusion was shorter with three screws
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