Kongsgaard M, Nielsen C H, Hegnsvad S, Aagaard P, Magnusson S P
Institute of Sports Medicine, Dept. Othopedic Surgery M, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health Sciences, University of Copenhagen, Denmark.
Clin Biomech (Bristol). 2011 Aug;26(7):772-7. doi: 10.1016/j.clinbiomech.2011.02.011. Epub 2011 Mar 9.
Ultrasonography has been widely applied for in vivo measurements of tendon mechanical properties. Assessments of human Achilles tendon mechanical properties have received great interest. Achilles tendon injuries predominantly occur in the tendon region between the Achilles-soleus myotendinous junction and Achilles-calcaneus osteotendinous junction i.e. in the free Achilles tendon. However, there has been no adequate ultrasound based method for quantifying the mechanical properties of the free human Achilles tendon. This study aimed to: 1) examine the mechanical properties of the free human Achilles tendon in vivo by the use of ultrasonography and 2) assess the between-day reproducibility of these measurements.
Ten male subjects had the Achilles tendon moment arm length, Achilles tendon cross sectional area and free Achilles tendon length determined. All subjects performed isometric plantarflexion ramp contractions to assess between-day reproducibility on two separate days. Simultaneous ultrasonography based measurements of Achilles-soleus myotendinous junction and Achilles-calcaneus osteotendinous junction displacement together with Achilles tendon force estimates yielded free Achilles tendon mechanical properties.
Free Achilles tendon maximal force, deformation and stiffness were 1924 (SD 229) N, 2.2 (SD 0.6) mm and 2622 (SD 534) N/mm on day 1. For between-day reproducibility there were no significant differences between days for free Achilles tendon mechanical properties. The between-day correlation coefficient and typical error percent were 0.81 and 5.3% for maximal Achilles tendon force, 0.85 and 11.8% for maximal Achilles tendon deformation and 0.84 and 8.8% for Achilles tendon stiffness respectively. Last, osteotendinous junction proximal displacement on average contributed with 71 (SD 12) % of proximal myotendinous junction displacement.
This study, for the first time, presents an ultrasonography based in vivo method for measurement of free AT mechanical properties. The method is applicable for evaluation of free human Achilles tendon mechanical properties in relation to training, injury and rehabilitation.
超声检查已广泛应用于肌腱力学特性的体内测量。对人类跟腱力学特性的评估受到了极大关注。跟腱损伤主要发生在跟腱 - 比目鱼肌肌腱连接点与跟腱 - 跟骨骨腱连接点之间的肌腱区域，即游离跟腱部位。然而，目前尚无足够的基于超声的方法来量化游离人类跟腱的力学特性。本研究旨在：1）通过超声检查在体内检测游离人类跟腱的力学特性；2）评估这些测量结果在不同日期之间的可重复性。
对10名男性受试者测定跟腱力臂长度、跟腱横截面积和游离跟腱长度。所有受试者在两个不同日期进行等长跖屈斜坡收缩，以评估不同日期之间的可重复性。基于超声同时测量跟腱 - 比目鱼肌肌腱连接点和跟腱 - 跟骨骨腱连接点的位移以及跟腱力估计值，从而得出游离跟腱的力学特性。
第1天，游离跟腱的最大力、变形和刚度分别为1924（标准差229）N、2.2（标准差0.6）mm和2622（标准差534）N/mm。对于不同日期之间的可重复性，游离跟腱力学特性在不同日期之间无显著差异。跟腱最大力的不同日期相关系数和典型误差百分比分别为0.81和5.3%，跟腱最大变形的为0.85和11.8%，跟腱刚度的为0.84和8.8%。最后，骨腱连接点近端位移平均占近端肌腱连接点位移的71（标准差12）%。
本研究首次提出了一种基于超声的体内测量游离跟腱力学特性的方法。该方法适用于评估游离人类跟腱在训练、损伤和康复方面的力学特性。
