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Early reattachment does not reverse atrophy and fat accumulation of the supraspinatus—an experimental study in rabbits
Article first published online: 1 JAN 2006
Copyright © 2003 Orthopaedic Research Society
Journal of Orthopaedic Research
Volume 21, Issue 3, pages 386–392, May 2003
How to Cite
Uhthoff, H. K., Matsumoto, F., Trudel, G. and Himori, K. (2003), Early reattachment does not reverse atrophy and fat accumulation of the supraspinatus—an experimental study in rabbits. J. Orthop. Res., 21: 386–392. doi: 10.1016/S0736-0266(02)00208-5
- Issue published online: 1 JAN 2006
- Article first published online: 1 JAN 2006
- Manuscript Accepted: 9 OCT 2002
- Manuscript Received: 12 JUL 2002
- American Shoulder and Elbow Surgeons
- Rotator cuff tear;
- Fibrocartilage reformation;
- Rotator cuff suture;
- Fat accumulation;
- Muscle atrophy
Introduction: Reattachment of the supraspinatus (SSP) tendon after spontaneous rupture leads to improved shoulder function. Whether this improvement of function is due to a reversal of muscle atrophy and fat accumulation known to occur after SSP rupture is still debated. Our previous study of late reattachment of SSP (12 weeks) failed to confirm a reversal of muscle atrophy and of fat accumulation.
Purpose: To find out whether earlier reattachment (6 weeks) reverses atrophy and fat accumulation of the SSP.
Material and methods: Reattachment group: in seven rabbits unilateral supraspinatus detachment, reattachment after 6 weeks and killing 6 weeks later. Detachment group: in seven rabbits unilateral supraspinatus detachment and killing 12 weeks later. The contralateral shoulders served as controls (n = 14). Determination of the supraspinatus constituents: muscle, extra- and intramuscular fat in volume and cross-sectional area.
Results: Muscle tissue in the reattachment group (8.6 ml ± 1 s.d. = 0.6) and in the detachment group (8.9 ml ± 0.9) were less than in control supraspinati (10.2 ml ± 0.9, both p < 0.05). Extra- and intramuscular fat in the reattachment group (8.7% ± 3.2) was greater than in both, the detachment group (4.6% ± 3.5), and control supraspinati (2.8% ± 1.7, both p < 0.05).
Conclusion: In the rabbit, reattachment of the SSP at 6 weeks did neither reverse muscle atrophy nor fat accumulation during the ensuing 6 weeks. However, earlier reattachment (6 weeks) when compared with later reattachment (12 weeks) prevented an increase in fat accumulation. On the other hand, the delay before reattaching the tendon did not lead to an increase in muscle atrophy.
© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.