Schickendantz M S, Watson J T, Sferra J J, Kambic H E
Department of Orthopaedic Surgery, Cleveland Clinic Foundation, Ohio.
Clin Orthop Relat Res. 1992 Feb(275):248-52.
In an effort to evaluate the strength of bones lengthened by distraction osteogenesis, a modified Ilizarov-type external fixator was applied to the right tibiae of five adult mongrel dogs. Diaphyseal corticotomies were performed, and distraction (lengthening) was carried out at a rate of approximately 1 mm per day for 20 days. After completion of the lengthening, the animals were killed, the fixators were removed, and the right and left tibiae were harvested and stripped of soft tissue. The ends of all harvested bones were fixated in polymethylmethacrylate to allow testing on a materials testing system (MTS) machine. Testing under torsional loads was performed on the MTS machine (50 degrees maximum angle of rotation at ten seconds) until failure. The right tibiae were lengthened an average of 12 mm (range, 7-15 mm). The slopes of the linear portion of the torque versus rotation curves were determined. A comparison of slopes revealed a mean change in stiffness between test and control bones of 20.32% (range, 0.64%-40.5%). All tibiae exhibiting mature regenerate bone demonstrated stiffness greater than the matched controls (range, 0.64-24.09% stiffer). Four of five dogs had problems with proximal and distal ring impingement. This study presents a reproducible model for evaluating the strength of bones lengthened by distraction osteogenesis. The lengthened bones that exhibited bony or mature regeneration were as strong as the control bones.
为了评估牵张成骨延长后的骨强度，将一种改良的伊利扎罗夫式外固定器应用于5只成年杂种犬的右胫骨。进行骨干皮质切开术，并以每天约1毫米的速度进行牵张（延长），持续20天。延长完成后，处死动物，拆除固定器，取出左右胫骨并去除软组织。将所有取出的骨头的两端固定在聚甲基丙烯酸甲酯中，以便在材料测试系统（MTS）机器上进行测试。在MTS机器上进行扭转载荷测试（十秒内最大旋转角度为50度），直至失效。右胫骨平均延长12毫米（范围为7 - 15毫米）。确定扭矩与旋转曲线线性部分的斜率。斜率比较显示，测试骨与对照骨之间的刚度平均变化为20.32%（范围为0.64% - 40.5%）。所有表现出成熟再生骨的胫骨的刚度均大于匹配的对照骨（刚度高0.64% - 24.09%）。五只犬中有四只出现近端和远端环撞击问题。本研究提出了一种可重复的模型，用于评估牵张成骨延长后的骨强度。表现出骨或成熟再生的延长骨与对照骨一样坚固。
