Life Sciences & Biomedicine Orthopedics Science & Technology Surgery
Background: Surgical repairs of torn rotator cuff tendons frequently fail. Immobilization has been shown to improve tissue mechanical properties in an animal model of rotator cuff repair, and passive motion has been shown to improve joint mechanics in animal models of flexor tendon repair. Our objective was to determine if daily passive motion would improve joint mechanics in comparison with continuous immobilization in a rat rotator cuff repair model. We hypothesized that daily passive motion would result in improved passive shoulder joint mechanics in comparison with continuous immobilization initially and that there would be no differences in passive joint mechanics or insertion site mechanical properties after four weeks of remobilization.
Methods: A supraspinatus injury was created and was surgically repaired in sixty-five Sprague-Dawley rats. Rats were separated into three postoperative groups (continuous immobilization, passive motion protocol 1, and passive motion protocol 2) for two weeks before all underwent a remobilization protocol for four weeks. Serial measurements of passive shoulder mechanics (internal and external range of motion and joint stiffness) were made before surgery and at two and six weeks after surgery. After the animals were killed, collagen organization and mechanical properties of the tendon-to-bone insertion site were determined.
Results: Total range of motion for both passive motion groups (49% and 45% of the pre-injury values) was less than that for the continuous immobilization group (59% of the pre-injury value) at two weeks and remained significantly less following four weeks of remobilization exercise. Joint stiffness at two weeks was increased for both passive motion groups in comparison with the continuous immobilization group. At both two and six weeks after repair, internal range of motion was significantly decreased whereas external range of motion was not. There were no differences between the groups in terms of collagen organization or mechanical properties.
Conclusions: In this model, immediate postoperative passive motion was found to be detrimental to passive shoulder mechanics. We speculate that passive motion results in increased scar formation in the subacromial space, thereby resulting in decreased range of motion and increased joint stiffness. Passive motion had no effect on collagen organization or tendon mechanical properties measured six weeks after surgery.
The Effect of Postoperative Passive Motion on Rotator Cuff Healing in a Rat Model
Creators
Cathryn D. Peltz - University of Pennsylvania
LeAnn M. Dourte - University of Pennsylvania
Andrew F. Kuntz - University of Pennsylvania
Joseph J. Sarver - University of Pennsylvania
Soung-Yon Kim - University of Pennsylvania
Gerald R. Williams - Thomas Jefferson University
Louis J. Soslowsky - University of Pennsylvania
Publication Details
Journal of bone and joint surgery. American volume, v 91A(10), pp 2421-2429
Publisher
Lippincott Williams & Wilkins
Number of pages
9
Grant note
P30 AR050950 / Penn Center for Musculoskeletal Disorders
National Science Foundation; National Science Foundation (NSF)
R01AR051000 / NATIONAL INSTITUTE OF ARTHRITIS AND MUSCULOSKELETAL AND SKIN DISEASES; United States Department of Health & Human Services; National Institutes of Health (NIH) - USA; NIH National Institute of Arthritis & Musculoskeletal & Skin Diseases (NIAMS)
R01 AR051000 / National Institutes of Health; United States Department of Health & Human Services; National Institutes of Health (NIH) - USA
Resource Type
Journal article
Language
English
Academic Unit
School of Biomedical Engineering, Science, and Health Systems; Drexel University
Web of Science ID
WOS:000270519700015
Scopus ID
2-s2.0-70349909650
Other Identifier
991019323669104721
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