caa a22 4500 605460418 CHVBK 20210128100238.0 cr unu---uuuuu 210128e20150201xx s 000 0 eng 10.1007/s00167-014-3037-y doi (NATIONALLICENCE)springer-10.1007/s00167-014-3037-y Tendon response to pharmaco-mechanical stimulation of the chronically retracted rotator cuff in sheep [Elektronische Daten] [Karl Wieser, Mazda Farshad, Dominik Meyer, Philipp Conze, Brigitte von Rechenberg, Christian Gerber] Purpose: Chronic tearing of tendons is associated with molecular and structural alterations causing biomechanical changes, which compromise musculotendinous function and become limiting factors for tendon repair. This study investigated the histological response of chronically retracted sheep rotator cuff tendons to mechanical and pharmacological stimulation in view of tendon repair. Methods: Sixteen weeks after experimental release of the infraspinatus tendon in 20 sheep, the retracted musculotendinous unit was subjected to continuous traction either with [anabolic steroids (nandrolone) group/insulin-like growth factor (IGF) group] or without (control group) additional pharmacological treatment during 6weeks. A new degeneration score for tendinous tissues (DSTT), based on established knowledge on histological changes associated with tendon degeneration, was used for histological analysis at the time of tendon release, at the beginning of continuous re-lengthening and at repair in all animals. Results: The DSTT score (inter-observer correlation: r=0.83), quantifiably representing tendon degeneration, improved from 15.5 (SD 1.3) points before to 9.8 (SD 3.8) points after re-lengthening. It improved in a qualitatively and quantitatively similar fashion if pharmacological stimulation was added. The nandrolone group improved from 13.7 (SD 1.6) to 9.8 (SD 1.9) and the IGF group from 13.3 (SD 3.6) to 8.8 (SD 1.8) points. Conclusion: Mechanical stimulation significantly reduced tissue degeneration. However, the addition of a pharmacological stimulation with anabolic steroids or IGF had neither a measurable positive nor negative effect on the degenerative process. Therefore, this investigation does neither support the additional pharmacological use of the anabolic steroid nandrolone or of IGF decanoate for restoration of tendon degeneration, nor otherwise provide evidence for additional tendon damage, if those substances are used to alter the muscular metabolism. Springer-Verlag Berlin Heidelberg, 2014 Tendon degeneration nationallicence Rotator cuff nationallicence Sheep rotator cuff model nationallicence Pharmaco-mechanical stimulation nationallicence Tendon re-lengthening nationallicence Anabolic steroids nationallicence Nandrolone nationallicence IGF nationallicence Wieser Karl Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland aut Farshad Mazda Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland aut Meyer Dominik Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland aut Conze Philipp Musculoskeletal Research Unit, Equine Department, Center for Applied Biotechnology and Molecular Medicine, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland aut von Rechenberg Brigitte Musculoskeletal Research Unit, Equine Department, Center for Applied Biotechnology and Molecular Medicine, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland aut Gerber Christian Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland aut Knee Surgery, Sports Traumatology, Arthroscopy Springer Berlin Heidelberg 23/2(2015-02-01), 577-584 0942-2056 23:2<577 2015 23 167 https://doi.org/10.1007/s00167-014-3037-y text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00167-014-3037-y text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Wieser Karl Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland aut NATIONALLICENCE 700 1- Farshad Mazda Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland aut NATIONALLICENCE 700 1- Meyer Dominik Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland aut NATIONALLICENCE 700 1- Conze Philipp Musculoskeletal Research Unit, Equine Department, Center for Applied Biotechnology and Molecular Medicine, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland aut NATIONALLICENCE 700 1- von Rechenberg Brigitte Musculoskeletal Research Unit, Equine Department, Center for Applied Biotechnology and Molecular Medicine, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland aut NATIONALLICENCE 700 1- Gerber Christian Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland aut NATIONALLICENCE 773 0- Knee Surgery, Sports Traumatology, Arthroscopy Springer Berlin Heidelberg 23/2(2015-02-01), 577-584 0942-2056 23:2<577 2015 23 167