Järvinen Tero A H, Järvinen Teppo L N, Kannus Pekka, Józsa László, Järvinen Markku
The Burnham Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA.
J Orthop Res. 2004 Nov;22(6):1303-9. doi: 10.1016/j.orthres.2004.04.003.
To study collagen fibre thickness and crimp formation in healthy and ruptured human tendons.
The thickness, crimp angle and wavelength of the collagen fibres were analyzed by interference and polarization microscopy and the samples were studied by transmission and scanning electron microscopy in four different healthy human tendons (Achilles, Quadriceps, Biceps brachii and Extensor pollicis longus) and in 66 spontaneously ruptured tendons.
In the normal (healthy) tendons, the diameter and crimp angle of the collagen fibres varied greatly between the four different tendons, the thickest fibres with the largest crimp angle being in the Achilles and Quadriceps tendons, whereas the Biceps brachii and Extensor pollicis longus, tendons that bear lighter strains but carry functions of high specificity, were found to have substantially smaller collagen fibres with lower crimp angle. Ruptured tendons had significantly smaller collagen fibre diameter than the normal tendons, the fibre diameter being -36% in comparison to their healthy counterparts in the Achilles tendons (P < 0.0001), -24% in the Quadriceps tendons (P < 0.0001), -37% in the Biceps brachii (P < 0.0001) and -14% in the Extensor pollicis longus (P = 0.10), respectively. Similarly, the crimp angle of the collagen fibres was also found to be lower in the ruptured tendons than in healthy, normal tendons. Further, the collagen fibres in the ruptured human tendons showed great variation in the crimp angle between the adjacent fibres and in the successive crimps of the same fibre.
Our results show that spontaneously ruptured tendons display focal regions with decreased collagen fibre thickness, decreased crimp angle and disrupted crimp continuity, microscopic alterations that possibly result in reduced strength of the tendons being less resistant to tensile forces, and thus, place them at increased risk of ruptures.
研究健康和断裂的人类肌腱中胶原纤维的厚度和卷曲形成情况。
通过干涉和偏振显微镜分析胶原纤维的厚度、卷曲角度和波长，并在4条不同的健康人类肌腱（跟腱、股四头肌肌腱、肱二头肌肌腱和拇长伸肌肌腱）以及66条自发性断裂的肌腱中，利用透射电子显微镜和扫描电子显微镜对样本进行研究。
在正常（健康）肌腱中，4条不同肌腱的胶原纤维直径和卷曲角度差异很大，跟腱和股四头肌肌腱中的纤维最厚且卷曲角度最大，而承受较轻应变但具有高特异性功能的肱二头肌肌腱和拇长伸肌肌腱的胶原纤维明显更细，卷曲角度更小。断裂的肌腱胶原纤维直径明显小于正常肌腱，跟腱中与健康对应部位相比纤维直径减少了36%（P < 0.0001），股四头肌肌腱中减少了24%（P < 0.0001），肱二头肌肌腱中减少了37%（P < 0.0001），拇长伸肌肌腱中减少了14%（P = 0.10）。同样，断裂肌腱中胶原纤维的卷曲角度也低于健康的正常肌腱。此外，人类断裂肌腱中的胶原纤维在相邻纤维之间的卷曲角度以及同一纤维的连续卷曲中显示出很大差异。
我们的结果表明，自发性断裂的肌腱显示出局部区域胶原纤维厚度降低、卷曲角度减小和卷曲连续性中断，这些微观改变可能导致肌腱强度降低，对拉力的抵抗力减弱，从而使其断裂风险增加。
