Wang Liren, Kang Yuhao, Wei Yiyao, Wang Mingqi, Gao Haihan, Shi Dingyi, Yu Suiran, Xie Guoming, Jiang Jia, Zhao Jinzhong
Department of Sports Medicine, Department of Orthopedics, Shanghai Institute of Microsurgery on Extremities, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, No. 600 Yishan Road, Shanghai, China.
Regenerative Sports Medicine and Translational Youth Science and Technology Innovation Workroom, Shanghai Jiao Tong University School of Medicine, No. 227 South Chongqing Road, Shanghai, China.
Knee Surg Sports Traumatol Arthrosc. 2023 May;31(5):1865-1872. doi: 10.1007/s00167-022-07044-w. Epub 2022 Jul 27.
To examine the biomechanical properties governing posterosuperior rotator cuff (RC) tear progression and dynamic shoulder abduction function, in the absence of excess loading.
Twelve freshly frozen cadaveric shoulders were evaluated via an established dynamic shoulder abduction stimulator. The shoulder abduction functions were primarily evaluated using subacromial contact pressure (SACP) during an abduction procedure, and subsequent middle deltoid force (MDF) under 5 conditions: (1) intact, (2) anterior 1/3 posterosuperior rotator cuff (PSRC) tear, (3) anterior 2/3 PSRC tear, (4) entire PSRC tear, and (5) global RC tear (tear involving the entire superior RC).
No obvious differences were observed in the peak MDF required for abduction, and in the peak SACP among the four PSRC tear statuses (49.8 ± 9.2 N, 0.39 ± 0.05 mPa [1/3 PSRC tear]; 49.3 ± 6.8 N, 0.40 ± 0.06 mPa [2/3 PSRC tear]; 51.6 ± 7.0 N, 0.44 ± 0.08 mPa [entire PSRC tear]), as well as intact statuses (48.3 ± 9.8 N, 0.40 ± 0.05 mPa). However, significant elevations in the peak MDF and peak SACP levels were observed among the four PSRC tear statuses and global RC tear (68.1 ± 9.3 N; 4.12 ± 1.50 mPa, P < 0.01).
In the absence of excess loading, the biomechanical function of the shoulder was not impaired by a simple PSRC tear. However, once the tear size reached the half superior portion of the humeral head, the humeral head migrated to the surface of the subacromion, and this action markedly decreased shoulder abduction function.
在无过度负荷的情况下，研究影响后上肩袖（RC）撕裂进展及动态肩关节外展功能的生物力学特性。
通过已建立的动态肩关节外展刺激器对12个新鲜冷冻尸体肩关节进行评估。在肩关节外展过程中，主要利用肩峰下接触压力（SACP）评估肩关节外展功能，随后在5种情况下评估三角肌中部力量（MDF）：（1）完整状态；（2）后上肩袖（PSRC）前1/3撕裂；（3）PSRC前2/3撕裂；（4）PSRC完全撕裂；（5）全层肩袖撕裂（撕裂累及整个上肩袖）。
在四种PSRC撕裂状态（49.8±9.2 N，0.39±0.05 mPa[1/3 PSRC撕裂]；49.3±6.8 N，0.40±0.06 mPa[2/3 PSRC撕裂]；51.6±7.0 N，0.44±0.08 mPa[PSRC完全撕裂]）以及完整状态（48.3±9.8 N，0.40±0.05 mPa）下，外展所需的峰值MDF和峰值SACP均未观察到明显差异。然而，在四种PSRC撕裂状态和全层肩袖撕裂（68.1±9.3 N；4.12±1.50 mPa，P<0.01）中，峰值MDF和峰值SACP水平显著升高。
在无过度负荷的情况下，单纯的PSRC撕裂不会损害肩关节的生物力学功能。然而，一旦撕裂大小达到肱骨头上方一半区域，肱骨头就会移至肩峰下表面，这种动作会显著降低肩关节外展功能。
