Grubor Predrag, Grubor Milan, Asotic Mithat
Clinic of Orthopedics and Traumatology, Clinical Center of University of Banja Luka, Bosnia and Herzegovina' Medical Faculty, University of Banja Luka, Bosnia and Herzegovina.
Med Arh. 2011;65(3):157-9. doi: 10.5455/medarh.2011.65.157-159.
Stabilization of fractures by external fixator is based on the mechanical connecting of the pins, screwed into the proximal and distal bone fragment. Site of fracture is left without any foreign materials, which is essential for prevention of infections. Aim of this work is to compare stability of constructs bone model-external fixators of different types (Ortofix, Mitković, Charneley and Ilizarov). Stability is estimated under compression and bending (vertical and horizontal forces of 100 kg magnitudes, with distances between pins of4 cm).
The mathematical-computer software (Tower, Planet and Planet Pro) was used in the laboratory for accurate measurements of MDP "Jelsingrad" company, Banjaluka. Interfragmental motions in millimeters at the appliance of vertical and horizontal forces were 2.80/2.56 at Ortofix (uniplanar fixator), 1.57/1.56 and fixator by Mitković-M20 (uniplanar fixator with convergent oriented pins), 0.16/0.28 at Charnely's external fixator (biplanar fixator), and 4.49/0.114 mm at Ilizarov's external fixator (fixator with two proximal and two distal rings, each attached on the 6 Kirschner wires).
It has confirmed that uniplanar fixation is easier and provides sufficient biomechanics circumstances in the site of fracture for bone healing, especially if the pins are oriented convergently. Ilizarov's fixator is multiplanar fixator, but its stability is dependent of tightness of wires, and provides adequate stability only in transversal plane. By other words, each fixator has its indications; selection of the fixator should be based on theirs mechanic characteristics, fracture geometry, and potential of bone healing, with permanent simplification of treatment, which has to be safe and acceptable for the patient. The main advantage of this study is Sits nature-the comparison of four most used external fixators, by the only one possible way-on the bone model. Each other way of comparison would result with much more questions than answers, due to unacceptable high bias of other parameters, which significantly influences on the results of the study.
外固定器对骨折的固定是基于将拧入近端和远端骨碎片的钢针进行机械连接。骨折部位不放置任何异物，这对预防感染至关重要。本研究的目的是比较不同类型（奥托菲克斯、米特科维奇、查利尼和伊里扎洛夫）的骨模型 - 外固定器结构的稳定性。在压缩和弯曲（100千克大小的垂直和水平力，钢针间距为4厘米）情况下评估稳定性。
在巴尼亚卢卡的“耶尔辛格拉德”公司实验室使用数学 - 计算机软件（Tower、Planet和Planet Pro）进行精确测量。在施加垂直和水平力时，奥托菲克斯（单平面固定器）的骨折块间运动（毫米）为2.80/2.56，米特科维奇 - M20固定器（带汇聚定向钢针的单平面固定器）为1.57/1.56，查利尼外固定器（双平面固定器）为0.16/0.28，伊里扎洛夫外固定器（带有两个近端和两个远端环，每个环连接在6根克氏针上）为4.49/0.114毫米。
已证实单平面固定更容易，并且在骨折部位为骨愈合提供了足够的生物力学条件，特别是当钢针汇聚定向时。伊里扎洛夫固定器是多平面固定器，但其稳定性取决于钢丝的紧密度，并且仅在横向平面提供足够的稳定性。换句话说，每种固定器都有其适应证；固定器的选择应基于其力学特性、骨折几何形状和骨愈合潜力，同时要始终简化治疗，且治疗必须对患者安全且可接受。本研究的主要优点是其性质——通过唯一可行的方法在骨模型上比较四种最常用的外固定器。由于其他参数存在不可接受的高偏差，会对研究结果产生重大影响，其他任何比较方式带来的问题都将多于答案。
