Hu Jian-Zhong, Zhou Yong-Chun, Huang Li-Hua, Lu Hong-Bin
BMC Musculoskelet Disord. 2013 Aug 19;14:246. doi: 10.1186/1471-2474-14-246.
Current tendon repair techniques do not provide sufficient tensile strength at the repair site, and thus early active motion rehabilitation after tendon repair is discouraged. To enhance the post-operative tensile strength, we proposed and tested an internal fixation technique using a polycaprolactone (PCL) biofilm. PCL was chosen for its good biocompatibility, excellent mechanical strength, and an appropriate degradation time scale.
PCL biofilms were prepared by a modified melt-molding/leaching technique, and the physical and mechanical properties and in vitro degradation rate were assessed. The pore size distribution of the biofilm and the paratenon of native tendons were observed using scanning electron microscopy. Next, we determined whether this biofilm could enhance the tensile strength of repaired tendons. We performed tensile tests on rabbit Achilles tendons that were first lacerated and then repaired: 1) using modified Kessler suture combined with running peripheral suture ('control' group), or 2) using biofilm to wrap the tendon and then fixation with sutures ('biofilm' group). The influence of different repair techniques on tendon tensile strength was evaluated by mechanical testing.
The novel biofilm had supple texture and a smooth surface. The mean thickness of the biofilm was 0.25 mm. The mean porosity of the biofilm was 45.3%. The paratenon of the rabbit Achilles tendon had pores with diameters ranging from 1 to 9 μm, which were similar to the 4-12 μm diameter pores in the biofilm cross-section. The weight loss of the biofilms at 4 weeks was only 0.07%. The molecular weight of PCL biofilms did not change after immersion in phosphate buffered saline for 4 weeks. The failure loads of the biofilm were similar before (48 ± 9 N) and after immersion (47 ± 7 N, P > 0.1). The biofilm group had ~70% higher mean failure loads and 93% higher stiffness compared with the control group.
We proposed and tested an internal fixation technique using a PCL biofilm to enhance tendon repair. Internal fixation with the biofilm followed by standard suturing can significantly increase the tensile strength of tendon repair sites. This technique has the potential to allow active motion rehabilitation during the early post-operative period.
目前的肌腱修复技术在修复部位无法提供足够的拉伸强度，因此不提倡肌腱修复后早期进行主动运动康复。为提高术后拉伸强度，我们提出并测试了一种使用聚己内酯（PCL）生物膜的内固定技术。选择PCL是因其良好的生物相容性、出色的机械强度以及合适的降解时间尺度。
通过改良的熔融成型/浸出技术制备PCL生物膜，并评估其物理和机械性能以及体外降解速率。使用扫描电子显微镜观察生物膜和天然肌腱腱旁组织的孔径分布。接下来，我们确定这种生物膜是否能增强修复肌腱的拉伸强度。我们对先切断然后修复的兔跟腱进行拉伸试验：1）使用改良的凯斯勒缝合法结合连续周边缝合法（“对照组”），或2）使用生物膜包裹肌腱然后用缝线固定（“生物膜组”）。通过力学测试评估不同修复技术对肌腱拉伸强度的影响。
新型生物膜质地柔软，表面光滑。生物膜的平均厚度为0.25毫米。生物膜的平均孔隙率为45.3%。兔跟腱的腱旁组织有直径为1至9微米的孔隙，这与生物膜横截面中直径为4至1微米的孔隙相似。4周时生物膜的重量损失仅为0.07%。PCL生物膜在磷酸盐缓冲盐水中浸泡4周后分子量未发生变化。生物膜浸泡前后的破坏载荷相似（浸泡前为48±9牛，浸泡后为47±7牛，P>0.1）。与对照组相比，生物膜组的平均破坏载荷高约70%，刚度高93%。
我们提出并测试了一种使用PCL生物膜增强肌腱修复的内固定技术。生物膜内固定后进行标准缝合可显著提高肌腱修复部位的拉伸强度。该技术有可能允许在术后早期进行主动运动康复。
