Zenios Michalis, Oyadiji S Olutunde
*Royal Manchester Children's Hospital †School of Mechanical, Aerospace and Civil Engineering, University of Manchester, Manchester, UK.
J Pediatr Orthop. 2014 Sep;34(6):618-24. doi: 10.1097/BPO.0000000000000194.
The Taylor Spatial Frame (TSF) is a relatively new circular external fixator linked with a computer program used in limb reconstruction surgery. It is routinely used in our unit (Royal Manchester Children's Hospital) for pediatric tibial lengthening.
The case notes and radiographs of 17 children who underwent 18 tibial lengthenings were reviewed. The TSF was attached to the tibia using a hybrid fixation method in the safe zone with two 1.8 mm tensioned smooth wires and 2 anteriorly placed hydroxyapatite-coated pins. Mechanical compression testing of our TSF construct was performed and compared with a double-ring Ilizarov frame construct fixed with only tensioned wires.
Out of the 18 tibiae lengthened 14 (77.8%) had a significant anterior angulation (>10 degrees) at the end of the distraction period that was corrected with a residual TSF program, with no known long-term consequences. The mechanical tests showed that the Ilizarov frame showed a more symmetrical distribution of loading in compression when compared with the TSF. With increasing load the TSF had the tendency to angulate anteriorly, that is, the apex of the angulation was pointing toward the 2 pins.
The problem of anterior angulation observed in our clinical and mechanical studies is due to instability of the fixation of the proximal part of the frame. Surgical techniques that can improve the stability of the proximal fixation and promote symmetrical loading are discussed.
泰勒空间框架（TSF）是一种相对较新的环形外固定器，与用于肢体重建手术的计算机程序相连。在我们单位（皇家曼彻斯特儿童医院），它常用于小儿胫骨延长术。
回顾了17例接受18次胫骨延长术的儿童的病历和X光片。采用混合固定方法，在安全区域使用两根1.8毫米张紧的光滑钢丝和2根前置的羟基磷灰石涂层钢针将TSF固定于胫骨。对我们的TSF结构进行了机械压缩测试，并与仅用张紧钢丝固定的双环伊利扎罗夫框架结构进行了比较。
在延长的18根胫骨中，14根（77.8%）在牵张期结束时出现明显的前向成角（>10度），通过剩余的TSF程序得以矫正，且无已知的长期后果。机械测试表明，与TSF相比，伊利扎罗夫框架在压缩时的载荷分布更对称。随着载荷增加，TSF有向前成角的趋势，即成角的顶点指向2根钢针。
我们在临床和力学研究中观察到的前向成角问题是由于框架近端固定不稳定所致。讨论了可提高近端固定稳定性并促进对称载荷的手术技术。
