Full-thickness supraspinatus tears are associated with more synovial inflammation and tissue degeneration than partial-thickness tears

• Published in: Journal of shoulder and elbow surgery 2011-09, Vol.20 (6), p.917-927
• Main Authors: Shindle, Michael K., MD, Chen, Christopher C.T., PhD, Robertson, Catherine, MD, DiTullio, Alexandra E., BS, Paulus, Megan C., MD, Clinton, Camille M., MD, Cordasco, Frank A., MD, Rodeo, Scott A., MD, Warren, Russell F., MD
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Diseases of the osteoarticular system; Humans; Injuries of the limb. Injuries of the spine; Injury Severity Score; matrix metalloproteinase; Medical sciences; Middle Aged; Orthopedics; proinflammatory cytokines; Rotator Cuff - pathology; Rotator Cuff Injuries; Rotator cuff tear; synovial inflammation; Synovitis - etiology; Tendinopathy - etiology; Tendon Injuries - complications; Traumas. Diseases due to physical agents
• ISSN: 1058-2746; 1532-6500
• DOI: 10.1016/j.jse.2011.02.015

Background The objective of this study was to determine whether the tear size of a supraspinatus tendon correlated with synovial inflammation and tendon degeneration in patients who underwent shoulder arthroscopy for rotator cuff repair. We hypothesized that increased synovial inflammation would correlate with greater tear size of the supraspinatus tendon at the time of surgery. Materials and methods Tissue from the synovium, bursa, torn supraspinatus tendon, and subscapularis tendon was obtained from patients during shoulder arthroscopy to evaluate the messenger RNA expression of proinflammatory cytokines, tissue remodeling, and angiogenesis factors in the tendon, bursa, and synovium. Additional tissue was fixed to determine histologic changes including inflammation, vascular ingrowth, and collagen organization. Results Increased expression of interleukin 1β, interleukin 6, cyclooxygenase 2, matrix metalloproteinase (MMP) 9, and vascular endothelial growth factor was found in the synovium of patients with full-thickness tears versus partial-thickness tears ( P < .05). In the supraspinatus tendon, increased expression of MMP-1, MMP-9, MMP-13, and vascular endothelial growth factor was found in the full-thickness group. The upregulation of these genes in the full-thickness group was consistent with enhanced synovial inflammation, greater vascular ingrowth, and the loss of collagen organization in both supraspinatus and subscapularis tendons as determined by histology. Conclusion Increased synovial inflammation and tissue degeneration correlate with the tear size of the supraspinatus tendon. A better understanding of the relationship between synovial inflammation and the progression of tendon degeneration can help in the design of novel and effective treatments to limit the advancement of rotator cuff disease and to improve their clinical outcomes.