Background:Rotator cuff repair augmentation using biological materials has become popular in clinical practice to reduce the high retear rates associated with traditional repair techniques. Tissue engineering approaches, such as engineered tendon-fibrocartilage-bone composite (TFBC), have shown promise in enhancing the biological healing of rotator cuff tears in animals. However, previous studies have provided limited long-term data on TFBC repair outcomes. The effect of mechanical stimulation on TFBC has not been explored extensively.Purpose:To evaluate functional outcomes after rotator cuff repair with engineered TFBC subjected to mechanical stimulation in a 6-month follow-up using a canine in vivo model.Study Design:Controlled laboratory study.Methods:A total of 40 canines with an acute infraspinatus (ISP) tendon transection model were randomly allocated to 4 groups (n =10): (1) unilateral ISP tendon undergoing suture repair only (control surgery); (2) augmentation with engineered TFBC alone (TFBC); (3) augmentation with engineered TFBC and bone marrow-derived stem cells (BMSCs) (TFBC+C); and (4) augmentation with engineered TFBC and BMSCs, as well as mechanical stimulation (TFBC+C+M). Outcome measures—including biomechanical evaluations such as failure strength, stiffness, failure mode, gross appearance, ISP tendon and muscle morphological assessment, and histological analysis—were performed 6 months after surgery.Results:As shown in the mechanical test, the TFBC+C+M group exhibited higher failure strength compared with other repair techniques. The most common failure mode was avulsion fracture in the TFBC+C+M group, but tendon-bone junction rupture was observed predominantly in different groups. Engineered TFBC with mechanical stimulation showed over 70% relative failure strength compared with normal ISP, and the other groups showed about 50% relative failure strength. Histological analysis revealed less fat infiltration and closer-to-normal muscle fiber structure in the mechanical stimulation group.Conclusion:This study provides evidence that mechanical stimulation of engineered TFBC promotes rotator cuff regeneration, thus supporting its potential for rotator cuff repair augmentation.Clinical Relevance:This study provides valuable evidence supporting the use of a novel tissue-engineered material (TFBC) in rotator cuff repair and paves the way for advancements in the field of rotator cuff regeneration.

中文翻译：

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机械刺激工程肌腱-纤维软骨-骨复合增强肩袖修复：一项使用体内犬模型进行 6 个月随访的研究


背景： 使用生物材料的肩袖修复增强术在临床实践中已变得流行，以降低与传统修复技术相关的高再撕裂率。组织工程方法，如工程肌腱-纤维软骨-骨复合 （TFBC），在增强动物肩袖撕裂的生物愈合方面显示出前景。然而，以前的研究提供的关于 TFBC 修复结果的长期数据有限。机械刺激对 TFBC 的影响尚未得到广泛探索。目的： 在为期 6 个月的随访中，使用犬体内模型评估工程化 TFBC 进行机械刺激的肩袖修复后的功能结局。研究设计： 对照实验室研究。方法： 将 40 只采用急性冈下肌 （ISP） 肌腱横断模型的犬随机分为 4 组 （n =10）： （1） 仅接受缝合修复的单侧 ISP 肌腱 （对照手术）;（2） 单独使用工程化 TFBC （TFBC） 进行增强;（3） 用工程化 TFBC 和骨髓来源的干细胞 （BMSC） （TFBC+C） 进行增强;（4） 使用工程化 TFBC 和 BMSC 以及机械刺激 （TFBC+C+M） 进行增强。术后 6 个月进行结果测量——包括生物力学评估，如失效强度、刚度、失效模式、大体外观、ISP 肌腱和肌肉形态学评估以及组织学分析。结果： 如力学试验所示，与其他修复技术相比，TFBC+C+M 组表现出更高的破坏强度。TFBC+C+M 组最常见的失败模式为撕脱性骨折，但不同组主要观察到肌腱-骨连接处断裂。 与正常 ISP 相比，机械刺激工程化 TFBC 显示出超过 70% 的相对失效强度，其他组显示出大约 50% 的相对失效强度。组织学分析显示，机械刺激组脂肪浸润较少，肌纤维结构更接近正常。结论： 本研究提供证据表明，工程化 TFBC 的机械刺激促进肩袖再生，从而支持其增强肩袖修复的潜力。临床相关性： 本研究提供了有价值的证据，支持在肩袖修复中使用新型组织工程材料 （TFBC），并为肩袖再生领域的进步铺平了道路。