Biomechanical comparison of different screw-included angles in crossing screw fixation for transverse patellar fracture in level walking: a quasi-dynamic finite element study

Abstract

Background A minimally invasive technique with various screw configurations without open surgery is currently used for the fixation of transverse patellar fractures. Percutaneous crossing screw configuration has been reported to have a good bone union rate in patellar fractures. However, the difference in mechanical stability of the fractured patella between different screw-included angles has not been fully investigated. Hence, this study aims to compare the mechanical stability of parallel and crossing screw fixations with different screw-included angles for the fixation of transverse patellar fractures during level walking. Methods A finite element knee model containing a patella with a transverse fracture is created. Two headless compression screws with different angles (0°, 30°, 60°, and 90°) are used to fix the fracture. The loading conditions of the knee joint during level walking are used to compare the stability of the fractured patella with different fixation screw configurations. Results The results indicate that the maximum fracture gap opening distance increased with an increase in the included angle. Two parallel screws yield the smallest gap distance among all screw configurations. The maximum gap opening distances at the anterior leading edge of the fractured patella with two parallel screws and two screws having an included angle of 90° are 0.73 mm and 1.31 mm, respectively, at 15% walking cycle. Conclusions Based on these results, the superior performance of two parallel screws over crossing screw fixations in the fixation of transverse patellar fractures is established. Furthermore, the smaller the angle between the crossing screws, the better is the stability of the fractured patella.

Tension band high-strength suture combined with absorbable cannulated screws for treating transverse patellar fractures: finite element analysis and clinical study

“…Remeshing, wrapping, and smoothing were performed using Geomagic Wrap 2021 (Geomagic, NC, United States) ( Mao et al, 2023 ). Finally, the TPF model (AO/OTA 34C1) was established using SolidWorks 2021 (Dassault, France) ( Chang et al, 2023 ) ( Figure 1B ).…”

Vibration Modeling and Analysis of a Flexible 3-PRR Planar Parallel Manipulator Based on Transfer Matrix Method for Multibody System

“…Therefore, by combining Equations ( 13), (16), and ( 21), the transfer equation of the mobile platform can be obtained as:…”

“…These methods have been widely used for modeling the dynamics of flexible parallel manipulators, especially the finite element method, which is the mainstream method for describing flexible body deformation in the dynamics of most flexible multibody systems because of its strong generality [14][15][16]. However, when these methods are used to calculate the vibration characteristics of rigid-flexible multibody systems, the global dynamics equations of the system must be established.…”