Supraspinatus and deltoid muscle fiber composition in rotator cuff tear conditions
© 2020 The Authors.
| Veröffentlicht in: | JSES international. - 2020. - 4(2020), 3 vom: 25. Sept., Seite 431-437 |
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| 1. Verfasser: | |
| Weitere Verfasser: | , , , , |
| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2020
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| Zugriff auf das übergeordnete Werk: | JSES international |
| Schlagworte: | Journal Article Muscle fiber type atrophy factors fiber diameter stereology type 1 type 2 |
| Zusammenfassung: | © 2020 The Authors. BACKGROUND: Rotator cuff (RC) tears are associated with RC muscle atrophy and changes in composition that are crucial to the prognosis of RC repair. The aim of this study was to characterize muscle fiber composition in the supraspinatus (SS) muscle under tear conditions METHODS: Muscle biopsies were obtained from 21 patients undergoing surgery for an RC tendon tear. Biopsies were obtained from the musculotendinous junction of the SS muscle, and control biopsies were harvested from the deltoid muscle (DT). Biopsies were immunohistochemically processed for detection of type 1 (slow type) and type 2 (fast type) fibers and analyzed using unbiased, stereological principles. We counted the total numbers of type 1 and 2 muscle fibers/mm2, and fiber diameter was used to estimate muscle fiber atrophy and hypertrophy RESULTS: We found significantly more type 2 cells/mm2 in the SS compared with the DT (P < .01). In addition, we found a significantly higher fraction of type 1 fibers than type 2 fibers in the DT (P < .01), whereas both fiber types were equally present in the SS. The diameters of SS cells were generally smaller than those of DT cells. Atrophy of especially SS type 2 fibers was also demonstrated. Fiber atrophy was more pronounced in men than women CONCLUSION: The changes in the composition of SS muscle cell types suggest a shift from type 1 to type 2 muscle fibers and atrophy of both type 1 and 2 fibers. This composition indicates loss of endurance and rapid fatigue of the SS muscle under RC tear conditions |
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| Beschreibung: | Date Revised 16.04.2022 published: Electronic-eCollection Citation Status PubMed-not-MEDLINE |
| ISSN: | 2666-6383 |
| DOI: | 10.1016/j.jseint.2020.04.016 |