Graduate School of Human Life Design, Toyo University, Oka 48-1, Asaka, Saitama, 351-8510, Japan.
Graduate School of Health Science, Hokkaido University, Sapporo, Hokkaido, Japan.
BMC Musculoskelet Disord. 2022 Mar 11;23(1):234. doi: 10.1186/s12891-022-05179-y.
Subacromial impingement (SAI) may be a cause of age-related rotator cuff abnormalities; therefore, the purpose of this study was to compare SAI characteristics between younger and older adults. In addition to the fact that thickened supraspinatus tendon (SST) indicates tendon abnormalities, SAI characteristics have been recognized as follows: greater SST thickness, reduced acromiohumeral distance (AHD), greater reduction of AHD (∆AHD) with arm elevation, and a higher percentage of SST within AHD (i.e., occupation ratio: OcAHD). Furthermore, we investigated the relationships between SST thickness and AHD, as well as SST thickness and ∆AHD to clarify the effect of SAI on rotator cuff abnormalities.
Healthy younger (n = 18, 21-24-year-old) and older (n = 27, 45-80-year-old) adults without any shoulder symptoms participated in this study. We measured their SST thickness and AHD at rest and at arm elevation (30° and 60°) in the scapular plane using ultrasound, and calculated ∆AHD as the relative change expressed as a percentage of the baseline. OcAHD was expressed as the ratio of SST thickness at rest to AHD at rest and in elevated positions.
The older subjects had approximately one mm thicker SST (P = 0.003, 95% Confidence interval [CI] = 0.410 to 1.895) and approximately 1.0 to 1.3 mm greater AHD than the younger subjects (P = 0.011, 95%CI = 0.284 to 2.068 at rest; P = 0.037, 95%CI = 0.082 to 2.609 for 30° of arm elevation; P = 0.032, 95%CI = 0.120 to 2.458 for 60° of arm elevation). However, there were no differences in ΔAHD and OcAHD between the groups.
This study demonstrated that, compared with the younger subjects, the older subjects showed thicker supraspinatus tendon but no other SAI characteristics including decreases in AHD and increases in OcAHD. Thus, this study suggests that older subjects showed age-related SST abnormalities without SAI, although the magnitude of the differences in SST thickness is notably small and the clinical significance of this difference is unclear.
肩峰下撞击（SAI）可能是导致与年龄相关的肩袖异常的原因；因此，本研究旨在比较年轻和老年患者的 SAI 特征。除了增厚的冈上肌腱（SST）表示肌腱异常之外，SAI 特征还包括：更大的 SST 厚度、更小的肩峰肱骨头间距（AHD）、随着手臂抬高 AHD 减少更大（即，相对 AHD 减少：∆AHD），以及 AHD 内 SST 的百分比更高（即，占空比：OcAHD）。此外，我们还研究了 SST 厚度与 AHD 之间的关系，以及 SST 厚度与 ∆AHD 之间的关系，以阐明 SAI 对肩袖异常的影响。
本研究纳入了无任何肩部症状的健康年轻（n = 18，21-24 岁）和老年（n = 27，45-80 岁）成年人。我们使用超声在肩胛骨平面测量他们在休息和手臂抬高（30°和 60°）时的 SST 厚度和 AHD，并计算相对 AHD 变化，以百分比表示与基线的差异。OcAHD 表示休息时 SST 厚度与休息和抬高时 AHD 的比值。
与年轻组相比，老年组的 SST 厚度约厚 1 毫米（P = 0.003，95%置信区间[CI] = 0.410 至 1.895），AHD 约大 1.0 至 1.3 毫米（P = 0.011，95%CI = 休息时 0.284 至 2.068；手臂抬高 30°时 0.037，95%CI = 0.082 至 2.609；手臂抬高 60°时 0.032，95%CI = 0.120 至 2.458）。然而，两组之间的 ∆AHD 和 OcAHD 没有差异。
本研究表明，与年轻组相比，老年组的冈上肌腱更厚，但没有其他 SAI 特征，包括 AHD 减少和 OcAHD 增加。因此，本研究表明，尽管 SST 厚度差异的幅度显著较小，且这种差异的临床意义尚不清楚，但老年组表现出与年龄相关的 SST 异常而没有 SAI。
