OBJECTIVE External fixators are important for correcting length discrepancies and axis deformities in pediatric or trauma orthopedic surgery. Pin loosening is a common pitfall during therapy that can lead to pain, infection, and necessary revisions. This study aims to present clinical data using calcium titanate (CaTiO3) Schanz screws and to measure the fixation strength. PATIENTS AND METHODS 22 titanate screws were used for external fixators in 4 pediatric patients. Therapy was initiated to lengthen or correct axial deformities after congenital abnormalities. The maximum tightening torque was measured during implantation, and the loosening torque was measured during explantation. In addition, screws of the same type were used in a cadaver study and compared with stainless steel and hydroxyapatite-coated screws. 12 screws of each type were inserted in four tibias, and the loosening and tightening torque was documented. RESULTS The fixation index in the in vivo measurement showed a significant increase between screw insertion and extraction in three of the four patients. The pins were in situ for 91 to 150 days, and the torque increased significantly (P = 0.0004) from insertion to extraction. The cadaveric study showed lower extraction torques than insertion torques, as expected in this setting. The calculated fixation index was significantly higher in the CaTiO3 group than in the other groups (P = 0.0208 vs. HA and P < 0.0001 vs. steel) and in the HA group vs. plain steel group (P = 0.0448). CONCLUSION The calcium titanate screws showed favorable fixation strength compared to HA and stainless steel screws and should be considered in long-term therapy of external fixation.

中文翻译：

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新型钛酸钙松紧螺钉外固定架的效果评估。首次临床结果和尸体研究。

目的外固定架对于纠正儿童或创伤骨科手术中的长度差异和轴畸形很重要。销钉松动是治疗期间的常见陷阱，可导致疼痛，感染和必要的翻修。这项研究旨在提供使用钛酸钙（CaTiO3）Schanz螺钉的临床数据并测量固定强度。患者与方法4例儿科患者使用22枚钛酸酯螺钉作为外固定器。开始治疗以延长或纠正先天性异常后的轴向畸形。在植入过程中测量最大拧紧扭矩，并在植入过程中测量松动扭矩。此外，尸体研究中使用了相同类型的螺钉，并将其与不锈钢和羟基磷灰石涂层的螺钉进行了比较。将每种类型的12个螺钉插入四个胫骨中，并记录其松动和拧紧扭矩。结果在体内测量中的固定指数显示，在四名患者中的三名中，螺钉插入和拔出之间的固定指数显着增加。销在原位放置91至150天，从插入到拔出，扭矩均显着增加（P = 0.0004）。尸体研究显示，提取扭矩低于插入扭矩，如在此设置中所预期的那样。CaTiO3组的计算固着指数显着高于其他组（P = 0.0208对HA，P <0.0001对钢）以及HA组对普通钢组（P = 0.0448）。