Department of Orthopedics, Buddhachinaraj Hospital, Phitsanulok, Thailand.
Department of Mechanical Engineering, Faculty of Engineering at Sriracha, Kasetsart University, Sriracha, Chonburi, Thailand.
Med Eng Phys. 2023 Jan;111:103926. doi: 10.1016/j.medengphy.2022.103926. Epub 2022 Nov 17.
The optimal technique for managing distal femur fixation failure remains inconclusive. The author studied the efficacy of a combined proximal humerus locking compression plate (LCP-PH) and 3.5 mm reconstruction plate (LCP-RP) by finite element (FE) analysis and retrospectively described the clinical outcomes of the present technique in such difficult circumstances.
Biomechanical study setting included FE models of the distal femur with remaining holes from previous distal femur LCP (LCP-DF) fixation stabilized with three different constructs i.e., LCP-DF alone, LCP-DF-and-LCP-RP, as well as LCP-PH-and-LCP-RP. All settings were analyzed by using FE under physiological loads. Regarding the clinical series, the outcomes of 8 LCP-DF fixation failures operated on by the present technique were retrospectively reviewed.
High Implant stress of 911.2 MPa and elastic strain at fracture site of 200.8 µɛ were found when stabilized with LCP-DF. The constructs of LCP-DF-and-LCP-RP, and LCP-PH-and-LCP-RP presented lower implant stress compared to LCP-DF, 511.5, and 617.5 MPa, respectively. The elastic strain of both dual plating constructs was also 4-5 times lower than LCP-DF and differed from each other by approximately 10 µɛ. Regarding the clinical series, bony consolidation was achieved in all cases with a mean duration of 28.5 weeks (range 24-36). An average ROM of the affected knee was 115° (range 105-140). Regarding the KSS, 1 was determined to be excellent and 7 to be good.
By the biomechanical analysis and the clinical results, the construct of LCP-PH-and-LCP-RP could be an effective technique for revision surgery of LCP-DF fixation failure.
对于股骨远端固定失败的最佳处理技术仍存在争议。作者通过有限元（FE）分析研究了近端肱骨锁定加压钢板（LCP-PH）和 3.5mm 重建钢板（LCP-RP）联合应用的效果，并回顾性描述了该技术在这种困难情况下的临床效果。
生物力学研究包括股骨远端的 FE 模型，这些模型具有之前使用 LCP 固定的股骨远端的残留孔（LCP-DF），通过三种不同的结构进行稳定，即单独使用 LCP-DF、LCP-DF 和 LCP-RP，以及 LCP-PH 和 LCP-RP。所有设置均在生理负荷下通过 FE 进行分析。关于临床系列，回顾性分析了 8 例采用该技术治疗的 LCP-DF 固定失败患者的结果。
单独使用 LCP-DF 固定时，植入物的应力高达 911.2MPa，骨折部位的弹性应变达到 200.8µɛ。LCP-DF 和 LCP-RP 以及 LCP-PH 和 LCP-RP 的结构的植入物的应力分别比 LCP-DF 低 511.5MPa 和 617.5MPa。两种双板结构的弹性应变也比 LCP-DF 低 4-5 倍，彼此之间相差约 10µɛ。关于临床系列，所有病例均获得骨愈合，平均愈合时间为 28.5 周（范围 24-36 周）。受累膝关节的平均 ROM 为 115°（范围 105-140°）。根据 KSS，1 例为优，7 例为良。
通过生物力学分析和临床结果，LCP-PH 和 LCP-RP 的结构可以成为 LCP-DF 固定失败修复手术的有效技术。
