Kumar Rajeev, Gupta Anupam, Sharma V P, Mishra Sanjay
Department of Mechanical Engineering, Institute of Engineering and Technology, Lucknow, UP, India.
J Orthop Surg (Hong Kong). 2011 Apr;19(1):72-5. doi: 10.1177/230949901101900117.
To conduct an in vitro strength test for the Joshi External Stabilising System (JESS) for stabilisation of tibial fractures using a cadaveric tibia and steel rods.
The configuration of the JESS specimens was based on a 62-year-old man with a metaphyseal tibial fracture. Two types of JESS specimens were prepared, using either the tibia of an average male adult cadaver (n=1) or stainless steel cylindrical rods (n=3). The strength of the JESS rather than that of the rods was measured using a universal testing machine. The axial compressive load was gradually increased at 1 mm/min to 35 N. Axial deformation of the fracture fragment was recorded. Each experiment was repeated 3 times in identical manner. A finite element analysis of the JESS was developed. The axial compressive loads and corresponding interfragmentary displacement in the experimental specimens and in the finite element analysis were compared.
The mean strength of the JESS was 32.5 N/mm in experiments and 35.3 N/mm in finite element analysis; the difference was 8.4%. The interfragmentary displacement was directly proportional to the axial compressive load.
The strength of the JESS is one fourth of that of the Ilizarov fixator, and therefore not suitable for full load bearing activities.
使用尸体胫骨和钢棒对用于稳定胫骨骨折的乔希外部稳定系统（JESS）进行体外强度测试。
JESS标本的配置基于一名62岁患有胫骨近端骨折的男性。制备了两种类型的JESS标本，一种使用平均成年男性尸体的胫骨（n = 1），另一种使用不锈钢圆柱棒（n = 3）。使用万能试验机测量JESS的强度而非钢棒的强度。轴向压缩载荷以1毫米/分钟的速度逐渐增加至35牛。记录骨折碎片的轴向变形。每个实验以相同方式重复3次。对JESS进行了有限元分析。比较了实验标本和有限元分析中的轴向压缩载荷及相应的骨折块间位移。
实验中JESS的平均强度为32.5牛/毫米，有限元分析中为35.3牛/毫米；差异为8.4%。骨折块间位移与轴向压缩载荷成正比。
JESS的强度是伊里扎洛夫固定器强度的四分之一，因此不适合全负重活动。
