Acute and chronic rotator cuff tears remain challenging for therapy. A wide range of therapeutic approaches were developed but re-tears and postoperative complications occur regularly. Especially in elderly people, the natural regeneration processes are decelerated, and graft materials are often necessary to stabilize the tendon-to-bone attachment and to improve the healing process. We here investigated in a small animal model a newly developed electrospun polycaprolactone fiber implant coated with a chitosan-polycaprolactone graft copolymer and compared these implants biomechanically and histologically with either a commercially available porous polyurethane implant (Biomerix 3D Scaffold) or suture-fixed tendons. Fifty-one rats were divided into three groups of 17 animals each. In the first surgery, the left infraspinatus tendons of all rats were detached, and the animals recovered for 4 weeks. In the second surgery, the tendons were fixed with suture material only (suture-fixed group; n = 17), whereas in the two experimental groups, the tendons were fixed with suture material and the polyurethane implant (Biomerix scaffold group; n = 17) or the modified electrospun polycaprolactone fiber implant (CS-g-PCL scaffold group; n=17), respectively. The unaffected right infraspinatus tendons were used as native controls. After a recovery of 8 weeks, all animals were clinically inconspicuous. In 12 animals of each group, repaired entheses were biomechanically tested for force at failure, stiffness, and modulus of elasticity, and in five animals, repaired entheses were analyzed histologically. Biomechanically, all parameters did not differ statistically significant between both implant groups, and the entheses failed typically at the surgical site. However, with respect to the force at failure, the median values of the two implant groups were smaller than the median value of the suture-fixed group. Histologically, the modified polycaprolactone fiber implant showed no acute inflammation processes, a good infiltration with cells, ingrowth of blood vessels and tendinous tissue, and a normal fibrous ensheathment. Further improvement of the implant material could be achieved by additional implementation of drug delivery systems. Therewith, the used CS-g-PCL fiber mat is a promising basic material to reach the goal of a clinically usable graft for rotator cuff tear repair.

中文翻译：

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电纺丝壳聚糖包衣的聚己内酯移植物在肩袖撕裂修复中的可能性和局限性。

急性和慢性肩袖撕裂对于治疗仍然具有挑战性。已经开发了多种治疗方法，但经常会出现泪水和术后并发症。尤其是在老年人中，自然再生过程会减速，因此通常需要使用嫁接材料来稳定肌腱与骨骼之间的附着并改善愈合过程。我们在这里以小型动物模型研究了一种新开发的包覆有壳聚糖-聚己内酯接枝共聚物的电纺聚己内酯纤维植入物，并将这些植入物在生物力学和组织学上与市售的多孔聚氨酯植入物（Biomerix 3D Scaffold）或缝合固定的肌腱进行了比较。51只大鼠分为三组，每组17只动物。在第一次手术中 分离所有大鼠的左鼻下肌腱，使动物恢复4周。在第二次手术中，仅用缝合线材料固定肌腱（缝合固定组； n = 17），而在两个实验组中，用缝合线材料和聚氨酯植入物固定肌腱（Biomerix支架组； n = 17） ）或改良的电纺聚己内酯纤维植入物（CS-g-PCL支架组； n = 17）。将未受影响的右下鼻肌腱用作天然对照。恢复8周后，所有动物在临床上都不显眼。在每组的12只动物中，对修复的生物体进行了断裂力，刚度和弹性模量的生物力学测试，在5只动物中，对修复的生物体进行了组织学分析。生物力学上 两组植入物之间的所有参数在统计学上均无显着差异，并且植入通常在手术部位失败。然而，关于破坏力，两个植入物组的中值小于缝合线固定组的中值。从组织学上看，改性的聚己内酯纤维植入物没有显示出急性炎症过程，良好的细胞浸润，血管和腱组织向内生长以及正常的纤维鞘。植入物材料的进一步改进可以通过另外实施药物输送系统来实现。因此，使用过的CS-g-PCL纤维垫是一种有前途的基础材料，可以达到临床上可用于肩袖撕裂修复的移植物的目标。而且这些手术通常在手术部位失败。然而，关于破坏力，两个植入物组的中值小于缝合线固定组的中值。从组织学上看，改性的聚己内酯纤维植入物没有显示出急性炎症过程，良好的细胞浸润，血管和腱组织向内生长以及正常的纤维鞘。植入物材料的进一步改进可以通过另外实施药物输送系统来实现。因此，使用过的CS-g-PCL纤维毡是一种很有前途的基础材料，可以达到临床上可用于肩袖撕裂修复的移植物的目标。而且这些手术通常在手术部位失败。然而，关于破坏力，两个植入物组的中值小于缝合线固定组的中值。从组织学上看，改性的聚己内酯纤维植入物没有显示出急性炎症过程，良好的细胞浸润，血管和腱组织向内生长以及正常的纤维鞘。植入物材料的进一步改进可以通过另外实施药物输送系统来实现。因此，使用过的CS-g-PCL纤维毡是一种很有前途的基础材料，可以达到临床上可用于肩袖撕裂修复的移植物的目标。从组织学上看，改性的聚己内酯纤维植入物没有显示出急性炎症过程，良好的细胞浸润，血管和腱组织向内生长以及正常的纤维鞘。植入物材料的进一步改进可以通过另外实施药物输送系统来实现。因此，使用过的CS-g-PCL纤维毡是一种很有前途的基础材料，可以达到临床上可用于肩袖撕裂修复的移植物的目标。从组织学上看，改性的聚己内酯纤维植入物没有显示出急性炎症过程，良好的细胞浸润，血管和腱组织向内生长以及正常的纤维鞘。植入物材料的进一步改进可以通过另外实施药物输送系统来实现。因此，使用过的CS-g-PCL纤维毡是一种很有前途的基础材料，可以达到临床上可用于肩袖撕裂修复的移植物的目标。