Liren Wang1,2, Yuhao Kang1,2, Yiyao Wei2,3, Mingqi Wang2,3, Haihan Gao2,4, Dingyi Shi2,4, Suiran Yu5, Guoming Xie1, Jia Jiang6,7,8, Jinzhong Zhao9,10,11. 1. 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. 2. 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. 3. School of Basic Medical Science, Fudan University, No. 130 Dongan Road, Shanghai, China. 4. Shanghai Jiao Tong University School of Medicine, No. 227 South Chongqing Road, Shanghai, China. 5. School of Mechanical Engineering, Shanghai Jiao Tong University, No. 800 Dongchuan Road, Shanghai, China. 6. 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. jessicajj19@hotmail.com. 7. Regenerative Sports Medicine Lab of the Institute of Microsurgery on Extremities, Shanghai Jiao Tong University Affiliated Sixth People' Hospital, No. 600 Yishan Road, Shanghai, 200233, China. jessicajj19@hotmail.com. 8. 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. jessicajj19@hotmail.com. 9. 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. jzzhao@sjtu.edu.cn. 10. Regenerative Sports Medicine Lab of the Institute of Microsurgery on Extremities, Shanghai Jiao Tong University Affiliated Sixth People' Hospital, No. 600 Yishan Road, Shanghai, 200233, China. jzzhao@sjtu.edu.cn. 11. 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. jzzhao@sjtu.edu.cn.
Abstract
PURPOSE: To examine the biomechanical properties governing posterosuperior rotator cuff (RC) tear progression and dynamic shoulder abduction function, in the absence of excess loading. METHODS: 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). RESULTS: 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). CONCLUSION: 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.
PURPOSE: To examine the biomechanical properties governing posterosuperior rotator cuff (RC) tear progression and dynamic shoulder abduction function, in the absence of excess loading. METHODS: 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). RESULTS: 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). CONCLUSION: 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.
Authors: Patrick Dickerson; Stephan G Pill; Robert Longstaffe; Ellen Shanley; Charles A Thigpen; Michael J Kissenberth Journal: J Shoulder Elbow Surg Date: 2020-07 Impact factor: 3.019
Authors: Felix Dyrna; Neil S Kumar; Elifho Obopilwe; Bastian Scheiderer; Brendan Comer; Michael Nowak; Anthony A Romeo; Augustus D Mazzocca; Knut Beitzel Journal: Am J Sports Med Date: 2018-05-09 Impact factor: 6.202
Authors: Burak Altintas; Michael Scheidt; Victor Kremser; Robert Boykin; Sanjeev Bhatia; Kaveh R Sajadi; Scott Mair; Peter J Millett Journal: Am J Sports Med Date: 2020-03-19 Impact factor: 6.202