Department of Orthopedics, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
Department of Orthopedics, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
J Orthop Surg Res. 2023 Jan 2;18(1):5. doi: 10.1186/s13018-022-03482-x.
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.
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.
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.
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.
目前，一种无需开放性手术的微创技术，采用各种螺钉构型，用于固定横断髌骨骨折。经皮交叉螺钉构型已被报道在髌骨骨折中具有较高的骨愈合率。然而，不同螺钉夹角的髌骨骨折的机械稳定性差异尚未得到充分研究。因此，本研究旨在比较平行和交叉螺钉固定不同螺钉夹角在水平步行时固定横断髌骨骨折的机械稳定性。
建立包含横断髌骨骨折的有限元膝关节模型。使用两种不同角度（0°、30°、60°和 90°）的无头加压螺钉固定骨折。采用膝关节在水平步行时的加载条件，比较不同固定螺钉构型下骨折髌骨的稳定性。
结果表明，最大骨折间隙张开距离随夹角的增加而增加。两种平行螺钉在所有螺钉构型中产生的间隙距离最小。在 15%步行周期时，两平行螺钉和两螺钉成 90°夹角的骨折髌骨前缘最大间隙张开距离分别为 0.73mm 和 1.31mm。
基于这些结果，确立了在固定横断髌骨骨折方面，两平行螺钉优于交叉螺钉固定。此外，交叉螺钉的夹角越小，骨折髌骨的稳定性越好。
