OBJECTIVE  Screw loosening in fracture fixation poses a clinical risk which may lead to implant failure, particularly in poor bone quality. The objective of this study was to examine the effectiveness of a novel screw retention technology (SRT) for increased screw purchase in a large animal metatarsal fracture model. STUDY DESIGN  This was a biomechanical, radiographic, and histological study utilizing an ovine metatarsal fracture model. Twenty-four sheep metatarsi underwent 3-mm ostectomies and were repaired with a nine-hole plate and 3.5-mm screws placed in oversized 3.5-mm holes to simulate worst case revision surgeries (i.e. no initial screw thread bone contact). Sheep were sacrificed at 3, 6 or 12 weeks (n = 6 each) post-operation. Post-sacrifice, each surgically implanted screw underwent either destructive mechanical testing or histomorphometric analyses. RESULTS  Treated metatarsi showed improved screw retention and normal fracture healing. Significant improvement in breakout strength and pullout strength of screws treated with the SRT were found as a function of healing time. Histologically, bone ingrowth at the screw interface was also shown to significantly increase with healing time. Improvements in fracture healing, indicated by an increase in bone fraction and decrease in void space at the osteotomy, were also observed with healing time. CONCLUSION  The results demonstrate the effectiveness of the SRT as a method for improved screw retention in a rescue-screw type scenario.

中文翻译：

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羊Meta骨骨折模型中聚对苯二甲酸乙二醇酯螺钉固定技术的生物力学和组织学评估。

目的骨折固定中的螺钉松动会带来临床风险，这可能会导致植入失败，尤其是在骨质较差的情况下。这项研究的目的是检验一种新型的螺钉固定技术（SRT）在大型动物meta骨骨折模型中增加螺钉购买的有效性。研究设计这是一项利用羊meta骨骨折模型进行的生物力学，射线照相和组织学研究。24只绵羊meta骨接受了3 mm的造口术，并用9孔板和3.5 mm的螺钉（其大小超过3.5 mm的螺钉）进行了修复，以模拟最坏情况下的翻修手术（即没有最初的螺纹骨接触）。术后3、6或12周（每组n = 6）处死绵羊。牺牲后 每个手术植入的螺钉都进行了破坏性的机械测试或组织形态分析。结果经治疗的meta骨显示出改善的螺钉固位和正常的骨折愈合。发现SRT处理的螺钉的断裂强度和拉拔强度有显着改善，这与愈合时间有关。从组织学上看，螺钉界面处的骨向内生长随着愈合时间的增加而显着增加。随着愈合时间的延长，也观察到骨折愈合的改善，这是由骨部分增加和截骨处的空隙减少所表明的。结论结果证明了SRT作为一种在抢救式螺钉情况下改善螺钉固定性的方法的有效性。发现SRT处理的螺钉的断裂强度和拉拔强度有显着改善，这与愈合时间有关。从组织学上看，螺钉界面处的骨向内生长随着愈合时间的增加而显着增加。随着愈合时间的延长，也观察到骨折愈合的改善，这是由骨部分增加和截骨处的空隙减少所表明的。结论结果证明了SRT作为一种在抢救式螺钉情况下改善螺钉固定性的方法的有效性。发现SRT处理的螺钉的断裂强度和拉拔强度有显着改善，这与愈合时间有关。从组织学上看，螺钉界面处的骨向内生长随着愈合时间的增加而显着增加。随着愈合时间的延长，也观察到骨折愈合的改善，这是由骨部分增加和截骨处的空隙减少所表明的。结论结果证明了SRT作为一种在抢救式螺钉情况下改善螺钉固定性的方法的有效性。随着愈合时间的延长，也观察到骨切开处的骨分数增加和空隙空间减少所指示的情况。结论结果证明了SRT作为一种在抢救式螺钉情况下改善螺钉固定性的方法的有效性。随着愈合时间的延长，也观察到骨切开处的骨分数增加和空隙空间减少所指示的情况。结论结果证明了SRT作为一种在抢救式螺钉情况下改善螺钉固定性的方法的有效性。