Khan K M, Cook J L, Bonar F, Harcourt P, Astrom M
School of Human Kinetics, University of British Columbia, Vancouver, Canada.
Sports Med. 1999 Jun;27(6):393-408. doi: 10.2165/00007256-199927060-00004.
Tendon disorders are a major problem for participants in competitive and recreational sports. To try to determine whether the histopathology underlying these conditions explains why they often prove recalcitrant to treatment, we reviewed studies of the histopathology of sports-related, symptomatic Achilles, patellar, extensor carpi radialis brevis and rotator cuff tendons. The literature indicates that healthy tendons appear glistening white to the naked eye and microscopy reveals a hierarchical arrangement of tightly packed, parallel bundles of collagen fibres that have a characteristic reflectivity under polarised light. Stainable ground substance (extracellular matrix) is absent and vasculature is inconspicuous. Tenocytes are generally inconspicuous and fibroblasts and myofibroblasts absent. In stark contrast, symptomatic tendons in athletes appear grey and amorphous to the naked eye and microscopy reveals discontinuous and disorganised collagen fibres that lack reflectivity under polarised light. This is associated with an increase in the amount of mucoid ground substance, which is confirmed with Alcian blue stain. At sites of maximal mucoid change, tenocytes, when present, are plump and chondroid in appearance (exaggerated fibrocartilaginous metaplasia). These changes are accompanied by the increasingly conspicuous presence of cells within the tendon tissue, most of which have a fibroblastic or myofibroblastic appearance (smooth muscle actin is demonstrated using an avidin biotin technique). Maximal cellular proliferation is accompanied by prominent capillary proliferation and a tendency for discontinuity of collagen fibres in this area. Often, there is an abrupt discontinuity of both vascular and myofibroblastic proliferation immediately adjacent to the area of greatest abnormality. The most significant feature is the absence of inflammatory cells. These observations confirm that the histopathological findings in athletes with overuse tendinopathies are consistent with those in tendinosis--a degenerative condition of unknown aetiology. This may have implications for the prognosis and timing of a return to sport after experiencing tendon symptoms. As the common overuse tendon conditions are rarely, if ever, caused by 'tendinitis', we suggest the term 'tendinopathy' be used to describe the common overuse tendon conditions. We conclude that effective treatment of athletes with tendinopathies must target the most common underlying histopathology, tendinosis, a noninflammatory condition.
肌腱疾病是竞技和休闲运动参与者面临的一个主要问题。为了确定这些病症背后的组织病理学是否能解释为何它们常常难以治疗，我们回顾了有关与运动相关的、有症状的跟腱、髌腱、桡侧腕短伸肌腱和肩袖肌腱组织病理学的研究。文献表明，健康的肌腱肉眼看上去呈闪亮的白色，显微镜检查显示，紧密排列的平行胶原纤维束呈分层排列，在偏振光下具有特征性的反射率。不存在可染色的基质（细胞外基质），血管也不明显。腱细胞通常不明显，不存在成纤维细胞和肌成纤维细胞。与之形成鲜明对比的是，运动员有症状的肌腱肉眼看上去呈灰色且无定形，显微镜检查显示胶原纤维不连续且排列紊乱，在偏振光下缺乏反射率。这与黏液样基质数量的增加有关，阿尔辛蓝染色证实了这一点。在黏液样变化最大的部位，若存在腱细胞，则其外观丰满且呈软骨样（过度的纤维软骨化生）。这些变化伴随着肌腱组织内细胞的日益明显，其中大多数具有成纤维细胞或肌成纤维细胞的外观（使用抗生物素蛋白 - 生物素技术可显示平滑肌肌动蛋白）。最大程度的细胞增殖伴随着明显的毛细血管增殖以及该区域胶原纤维的连续性倾向。通常，在紧邻最异常区域处，血管和肌成纤维细胞增殖会突然中断。最显著的特征是不存在炎性细胞。这些观察结果证实，患有过度使用性肌腱病的运动员的组织病理学发现与肌腱退变——一种病因不明的退行性病症——的发现一致。这可能对出现肌腱症状后恢复运动的预后和时机有影响。由于常见的过度使用性肌腱病症很少（如果有的话）是由“肌腱炎”引起的，我们建议使用“肌腱病”一词来描述常见的过度使用性肌腱病症。我们得出结论，对患有肌腱病的运动员进行有效治疗必须针对最常见的潜在组织病理学——肌腱退变，一种非炎性病症。
