Department of Orthopaedics and Traumatology, Yangjiang People's Hospital, No. 42 Dongshan Road, Jiangcheng District, 529500, Yangjiang, China.
Division of Orthopaedics and Traumatology, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, No. 1838 North Guangzhou Avenue, Guangzhou, 510515, China.
BMC Musculoskelet Disord. 2022 Aug 30;23(1):820. doi: 10.1186/s12891-022-05751-6.
The influence of thread profile on the fixation stability of bone screws remains unclear. This study aimed to compare the fixation stability of screws with different thread profiles under several loading conditions.
Bone screws that differed in thread profile (buttress, triangle, and square thread) only were made of stainless steel. Their fixation stabilities were evaluated individually by the axial pullout test and lateral migration test, besides, they were also evaluated in pairs together with a dynamic compression plate and a locking plate in polyurethane foam blocks under cyclic craniocaudal and torsional loadings.
The triangle-threaded and square-threaded screws had the highest pullout forces and lateral migration resistance. When being applied to a dynamic compression plate, higher forces and more cycles were required for both triangle- and square-threaded screws to reach the same displacement under cyclic craniocaudal loading. On the other hand, the triangle-threaded screws required a higher torque and more cycles to reach the same angular displacement under cyclic torsional loading. When being applied to a locking plate, the square-threaded screws needed higher load, torque, and more cycles to reach the same displacement under both cyclic craniocaudal and torsion loadings.
The triangle-threaded screws had superior pullout strength, while square-threaded screws demonstrated the highest lateral migration resistance. Moreover, dynamic compression plate fixation with triangle- and square-threaded screws achieved more favorable fixation stability under craniocaudal loading, while triangle-threaded screws demonstrated superior fixation stability under torsional loading. Locking plate fixation with a square-threaded screw achieved better fixation stability under both loading types.
螺纹形态对骨螺钉固定稳定性的影响尚不清楚。本研究旨在比较不同螺纹形态（梯形、三角形和方形螺纹）螺钉在几种加载条件下的固定稳定性。
仅改变螺纹形态的不锈钢骨螺钉被单独进行轴向拔出试验和侧向迁移试验，以评估其固定稳定性，同时与动力加压板和锁定板一起在聚氨酯泡沫块中进行循环颅尾向和扭转加载，以评估其配对固定稳定性。
梯形螺纹和方形螺纹螺钉具有最高的拔出力和侧向迁移阻力。当应用于动力加压板时，梯形和方形螺纹螺钉在循环颅尾向加载下达到相同位移需要更高的力和更多的循环。另一方面，在循环扭转加载下，达到相同角位移需要更高的扭矩和更多的循环。当应用于锁定板时，梯形和方形螺纹螺钉在循环颅尾向和扭转加载下达到相同位移需要更高的载荷、扭矩和更多的循环。
梯形螺纹螺钉具有较高的拔出强度，而方形螺纹螺钉表现出最高的侧向迁移阻力。此外，在颅尾向加载下，动力加压板固定采用梯形和方形螺纹螺钉具有更优的固定稳定性，而在扭转加载下，梯形螺纹螺钉具有更优的固定稳定性。锁定板固定采用方形螺纹螺钉在两种加载类型下均具有更好的固定稳定性。
