Merza Eman, Pearson Stephen, Lichtwark Glen, Garofolini Alessandro, Malliaras Peter
Department of Physiotherapy, Faculty of Medicine, Nursing and Health Science, Monash University, Melbourne, Australia.
Centre for Health, Sport and Rehabilitation Sciences Research, University of Salford, Greater Manchester, United Kingdom.
Ultrasound Med Biol. 2021 Apr;47(4):973-981. doi: 10.1016/j.ultrasmedbio.2021.01.002. Epub 2021 Jan 21.
Achilles tendon (AT) stiffness is an important property of both human locomotor performance and injury mechanics. Freehand 3-D ultrasound (3-DUS) is a promising method for measuring stiffness of the Achilles tendon, particularly the free AT (2-6 cm proximal to calcaneus), which is commonly injured. The aim of this study was to investigate the test-retest reliability of freehand 3-DUS in measuring free AT stiffness in humans. The free Achilles tendon length of healthy participants (n = 10) was scanned on the same day on two consecutive occasions (1 h apart) during rest and isometric plantar flexion contractions at 20%, 40% and 60% of maximum force. The slope of the force-elongation curve over these force levels represented individual stiffness (N/mm). Relative reliability was assessed using the intra-class correlation coefficient (ICC), and absolute reliability was estimated with the standard error of measurement (SEM) and smallest detectable change. Systematic bias in stiffness measures was explored by comparing test and retest distributions and Bland-Altman plots. The test-retest reliability of free AT stiffness measured using freehand 3-DUS was excellent [ICC = 0.994, 95% confidence interval [CI]: 0.978-0.999)]. The mean stiffness values at test (361.83 N/mm [170.77]) and retest (364.98 N/mm [168.57]) did not significantly differ (p = 0.72), and the smallest detectable change was 52.14 N/mm. The Bland-Altman plot indicated the absence of systematic bias (95% CI: -22.18 to 15.88). Freehand 3-DUS provides reliable and precise measures of tendon stiffness and can be used to detect small changes in free AT stiffness in response to load or tendon pathology.
跟腱（AT）的刚度是人体运动表现和损伤力学的一个重要特性。徒手三维超声（3-DUS）是一种很有前景的测量跟腱刚度的方法，尤其是在距跟骨近端2-6厘米处的游离跟腱，此处是常见的损伤部位。本研究的目的是探讨徒手三维超声测量人体游离跟腱刚度的重测信度。在同一天，对10名健康参与者的游离跟腱长度进行了两次连续扫描（间隔1小时），扫描时参与者处于休息状态以及在最大力的20%、40%和60%下进行等长跖屈收缩。这些力水平上的力-伸长曲线斜率代表个体刚度（N/mm）。使用组内相关系数（ICC）评估相对信度，并用测量标准误（SEM）和最小可检测变化估计绝对信度。通过比较测试和重测分布以及Bland-Altman图来探讨刚度测量中的系统偏差。使用徒手三维超声测量的游离跟腱刚度的重测信度极佳[ICC = 0.994，95%置信区间[CI]：0.978-0.999]。测试时的平均刚度值（361.83 N/mm [170.77]）和重测时的平均刚度值（364.98 N/mm [168.57]）无显著差异（p = 0.72），最小可检测变化为52.14 N/mm。Bland-Altman图表明不存在系统偏差（95% CI：-22.18至15.88）。徒手三维超声可提供可靠且精确的肌腱刚度测量，可用于检测游离跟腱刚度因负荷或肌腱病变而发生的微小变化。
