Biomechanics Laboratory, Division of Orthopaedic Surgery, Oslo University Hospital, Oslo 0424, Norway; Institute of Clinical Medicine, University of Oslo, Pb. 1171 Blindern, Oslo 0318, Norway.
Biomechanics Laboratory, Division of Orthopaedic Surgery, Oslo University Hospital, Pb. 4950 Nydalen, Oslo 0424, Norway.
J Biomech Eng. 2021 Jul 1;143(7). doi: 10.1115/1.4050282.
Fixation failure with resulting non-union is the key complication after femoral neck fixation. It can be avoided by permitting dynamic compression and reducing rotation and posterior tilt of the femoral head. To achieve this, a novel implant that features an interlocking plate with three hook-pins (The Hansson Pinloc® System) was developed from the original two hook-pins. Only an enhanced torsional fixation by the implant modification is reported. The purpose was to compare the biomechanical compressive and bending stability of the original and modified implant in femoral neck fixation. To analyze the contribution of both modified components, three individual pins were included, although not in regular use. Forty-eight synthetic femurs with mid-cervical wedge osteotomies were fixated by two pins or identical triangular pin patterns with or without the plate. Eight specimens of each group were loaded cyclically in compression with an inferior wedge to simulate stance and anteroposterior bending with a posterior wedge to imitate sitting down. The clinically relevant stability measurements were stiffness and deformation. Fissure formation defined failure. The novel implant improved bending stability by 30% increased stiffness, 44% reduced deformation, and less frequent posterior neck fissure formation (p < 0.001) while increased compressive stability was only evident with 25% reduced deformation and less frequent inferior neck fissures (p < 0.001). These impacts were mainly mediated by the third pin, while the plate prevented a lateral fissure in compression (p < 0.001). The clinical stability was improved by dynamic compression and decreased posterior tilt by implant modification.
固定失败导致的不愈合是股骨颈固定后的主要并发症。通过允许动态加压并减少股骨头的旋转和后倾，可以避免这种情况。为此，从最初的两钩钉开发出一种具有带三个钩钉的锁定板的新型植入物（Hansson Pinloc®系统）。仅报告了通过植入物修改增强的扭转固定。目的是比较股骨颈固定中原始和改良植入物的生物力学压缩和弯曲稳定性。为了分析两个改良组件的贡献，尽管未常规使用，但包含了三个单独的销钉。用两根钉或相同的三角形钉模式固定四十八个合成股骨颈中段楔形切开术，带有或不带有板。每组的八个标本在压缩下用下楔形物进行循环加载以模拟站立，用后楔形物进行前后弯曲以模拟坐下。临床相关的稳定性测量是刚度和变形。裂隙形成定义为失败。新型植入物通过增加刚度 30%，减少变形 44%，并减少后颈裂隙形成的频率（p<0.001），从而改善了弯曲稳定性，而仅通过减少变形 25%和减少下颈裂隙形成的频率（p<0.001），从而提高了压缩稳定性。这些影响主要由第三根钉介导，而板在压缩时防止了侧向裂缝（p<0.001）。通过植入物修改实现了动态加压和减少后倾，从而提高了临床稳定性。
