Plasticity of Muscle Architecture After Supraspinatus Tears
Plasticity of Muscle Architecture After Supraspinatus Tears
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DOI：
10.2519/jospt.2010.3279
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发表时间：
2010-11-01
影响因子：
6.1
通讯作者：
Lieber, Richard L.
中科院分区：
文献类型：
--
作者：
Ward, Samuel R.;Sarver, Joseph J.;Lieber, Richard L.
STUDY DESIGN Controlled laboratory studyOBJECTIVES To measure the architectural properties of rat supraspinatus muscle after a complete detachment of its distal tendonMETHODS Supraspinatus muscles were released from the left humerus of 29 Sprague Dawley rats (mass 400 450 g) and the animals were returned to cage activity for 2 weeks (n = 12) 4 weeks (n = 9) or 9 weeks (n = 8) before euthanasia Measurements of muscle mass perination angle fiber bundle length (sarcomere number) and sarcomere length permitted calculation of normalized fiber length serial sarcomere number and physiological cross sectional areaRESULTS Coronal oblique sections of the supraspinatus confirmed surgical transection of the supraspinatus muscle at 2 weeks with reattachment by 4 weeks Muscle mass and length were significantly lower in released muscles at 2 weeks 4 weeks and 9 weeks Sarcomere lengths in released muscles were significantly shorter at 2 weeks but not different by 4 weeks Sarcomere number was significantly reduced at 2 and 4 weeks but returned to control values by 9 weeks The opposing effects of smaller mass and shorter fibers produced significantly smaller physiological cross sectional area at 2 weeks but physiological cross sectional area returned to control levels by 4 weeksCONCLUSIONS Release of the supraspinatus muscle produced early radial and longitudinal atrophy of the muscle The functional implications of these adaptations would be most profound at early time points (particularly relevant for rehabilitation) when the muscle remains smaller in cross sectional area and due to reduced sarcomere number would be forced to operate over a wider range of the length tension curve and at higher velocities all adaptations resulting in compromised force generating capacity These data are relevant to physical therapy because they provide tissue level insights into impaired muscle and shoulder function following rotator cuff injury J Orthop Sports Phys Ther 2010 40(11) 729 735 doi 10.2519/jospt.2010.3279
