scholarly journals Fatty Infiltration Is a Prognostic Marker of Muscle Function After Rotator Cuff Tear

2018 ◽  
Vol 46 (9) ◽  
pp. 2161-2169 ◽  
Author(s):  
Ana P. Valencia ◽  
Jim K. Lai ◽  
Shama R. Iyer ◽  
Katherine L. Mistretta ◽  
Espen E. Spangenburg ◽  
...  
Keyword(s):  
Rotator Cuff ◽  
Muscle Atrophy ◽  
Muscle Function ◽  
Contractile Function ◽  
Isometric Force ◽  
Fatty Infiltration ◽  
Collagen Content ◽  
Strongly Correlated ◽  
Computed Tomography Scanning ◽  
Maximal Isometric Force

Background: Massive rotator cuff tears (RCTs) begin as primary tendon injuries and cause a myriad of changes in the muscle, including atrophy, fatty infiltration (FI), and fibrosis. However, it is unclear which changes are most closely associated with muscle function. Purpose: To determine if FI of the supraspinatus muscle after acute RCT relates to short-term changes in muscle function. Study Design: Controlled laboratory study. Methods: Unilateral RCTs were induced in female rabbits via tenotomy of the supraspinatus and infraspinatus. Maximal isometric force and rate of fatigue were measured in the supraspinatus in vivo at 6 and 12 weeks after tenotomy. Computed tomography scanning was performed, followed by histologic analysis of myofiber size, FI, and fibrosis. Results: Tenotomy resulted in supraspinatus weakness, reduced myofiber size, FI, and fibrosis, but no differences were evident between 6 and 12 weeks after tenotomy except for increased collagen content at 12 weeks. FI was a predictor of supraspinatus weakness and was strongly correlated to force, even after accounting for muscle cross-sectional area. While muscle atrophy accounted for the loss in force in tenotomized muscles with minimal FI, it did not account for the greater loss in force in tenotomized muscles with the most FI. Collagen content was not strongly correlated with maximal isometric force, even when normalized to muscle size. Conclusion: After RCT, muscle atrophy results in the loss of contractile force from the supraspinatus, but exacerbated weakness is observed with increased FI. Therefore, the level of FI can help predict contractile function of torn rotator cuff muscles. Clinical Relevance: Markers to predict contractile function of RCTs will help determine the appropriate treatment to improve functional recovery after RCTs.

Rotator Cuff Fatty Infiltration and Muscle Atrophy: Relation to Glenoid Deformity in Primary Glenohumeral Osteoarthritis

2021 ◽  
Author(s):  
Michael A. Moverman ◽  
Richard N. Puzzitiello ◽  
Mariano E. Menendez ◽  
Nicholas R. Pagani ◽  
Paul-Anthony J. Hart ◽  
...  
Keyword(s):  
Rotator Cuff ◽  
Muscle Atrophy ◽  
Fatty Infiltration ◽  
Glenohumeral Osteoarthritis

Does successful rotator cuff repair improve muscle atrophy and fatty infiltration of the rotator cuff?

2014 ◽  
Vol 23 (5) ◽  
pp. 604
Author(s):  
Noritaka Hamano ◽  
Atsushi Yamamoto ◽  
Tsutomu Kobayashi ◽  
Hitoshi Shitara ◽  
Tsuyoshi Ichinose ◽  
...  
Keyword(s):  
Rotator Cuff ◽  
Muscle Atrophy ◽  
Rotator Cuff Repair ◽  
Fatty Infiltration ◽  
Cuff Repair

scholarly journals Influenza Infection has Fiber Type-Specific Effects on Cellular and Molecular Skeletal Muscle Function in Aged Mice

2020 ◽  
Vol 75 (12) ◽  
pp. 2333-2341
Author(s):  
Chad R Straight ◽  
Olivia R Ringham ◽  
Jenna M Bartley ◽  
Spencer R Keilich ◽  
George A Kuchel ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Contractile Function ◽  
Isometric Force ◽  
Fiber Type ◽  
Influenza Infection ◽  
Fiber Types ◽  
Specific Force ◽  
Mhc Iia ◽  
Mhc Iib ◽  
Maximal Isometric Force

Abstract Skeletal muscle myopathies represent a common non-pulmonary manifestation of influenza infection, leading to reduced physical function and hospitalization in older adults. However, underlying mechanisms remain poorly understood. Our study examined the effects of influenza virus A pulmonary infection on contractile function at the cellular (single fiber) and molecular (myosin-actin interactions and myofilament properties) levels in soleus and extensor digitorum longus muscles of aged (20 months) C57BL/6 male mice that were healthy or flu-infected for 7 (7-days post-infection; 7-DPI) or 12 days (12-DPI). Cross-sectional area (CSA) of myosin heavy chain (MHC) IIA and IIB fibers was reduced at 12-DPI relative to 7-DPI and healthy. Maximal isometric force in MHC IIA fibers was also reduced at 12-DPI relative to 7-DPI and healthy, resulting in no change in specific force (maximal isometric force divided by CSA). In contrast, MHC IIB fibers produced greater isometric force and specific force at 7-DPI compared to 12-DPI or healthy. The increased specific force in MHC IIB fibers was likely due to greater myofilament lattice stiffness and/or an increased number or stiffness of strongly bound myosin-actin cross-bridges. At the molecular level, cross-bridge kinetics were slower in MHC IIA fibers with infection, while changes in MHC IIB fibers were largely absent. In both fiber types, greater myofilament lattice stiffness was positively related to specific force. This study provides novel evidence that cellular and molecular contractile function is impacted by influenza infection in a fiber type-specific manner, suggesting potential molecular mechanisms to help explain the impact of flu-induced myopathies.

MRI quantification of fatty infiltration and muscle atrophy in a mouse model of rotator cuff tears

2012 ◽  
Vol 31 (3) ◽  
pp. 421-426 ◽  
Author(s):  
Sanjum P. Samagh ◽  
Erik J. Kramer ◽  
Gerd Melkus ◽  
Dominique Laron ◽  
Blake M. Bodendorfer ◽  
...  
Keyword(s):  
Rotator Cuff ◽  
Mouse Model ◽  
Muscle Atrophy ◽  
Fatty Infiltration ◽  
Rotator Cuff Tears

scholarly journals Effect of Muscle Quality on Operative and Nonoperative Treatment of Rotator Cuff Tears

2019 ◽  
Vol 7 (8) ◽  
pp. 232596711986301
Author(s):  
Micah Naimark ◽  
Thai Trinh ◽  
Christopher Robbins ◽  
Bridger Rodoni ◽  
James Carpenter ◽  
...  
Keyword(s):  
Cohort Study ◽  
Rotator Cuff ◽  
Muscle Atrophy ◽  
Fatty Infiltration ◽  
Nonoperative Treatment ◽  
Nonsurgical Treatment ◽  
Muscle Quality ◽  
Rotator Cuff Tears ◽  
The Impact ◽  
Surgical Group

Background: Rotator cuff muscle atrophy and fatty infiltration are predictors of negative outcomes after rotator cuff repair. However, the impact of muscle degeneration on nonsurgical treatment is unknown. Hypothesis: Rotator cuff muscle atrophy and fatty infiltration will reduce the outcomes of operative repair while having a minimal effect on nonsurgical treatment. Additionally, in the setting of atrophy and fatty infiltration, surgical and nonsurgical treatment will produce equivalent outcomes. Study Design: Cohort study; Level of evidence, 2. Methods: Patients undergoing operative and nonoperative treatment of full-thickness rotator cuff tears were prospectively enrolled into a nonrandomized cohort study. Muscle quality was assessed on magnetic resonance imaging by use of the supraspinatus tangent sign, Warner atrophy, and Goutallier fatty infiltration classifications. Grading was performed by 2 independent observers who were blinded to patient treatment and outcomes. Normalized Western Ontario Rotator Cuff (WORC) index was the primary patient-reported outcome. Multivariate linear regression analysis was used to determine the impact of muscle quality on treatment outcomes. Results: The cohort consisted of 157 patients, 89 (57%) surgical and 68 (43%) nonsurgical, with a mean follow-up of 2.4 years (range, 1-5 years). Tangent sign had the best inter- and intrarater reliability, with kappa statistics of 0.81 and 0.86, respectively. Reliability for Warner atrophy was 0.69 to 0.76 and for Goutallier classification was 0.54 to 0.64. Overall, improvement in WORC scores was higher in the surgical group than the nonsurgical group (39.3 vs 21.2; P < .001). A positive tangent sign was the only independent predictor ( P < .01) of worse outcomes in the surgical group, accounting for an estimated 22-point lower improvement in WORC scores. Conclusion: A positive tangent sign was predictive of worse operative outcomes, resulting in equivalent improvements between surgical and nonsurgical treatment. The tangent sign is a reliable, prognostic indicator that clinicians can use when counseling patients on the optimal treatment of rotator cuff tears.

scholarly journals A Mouse Model of Delayed Rotator Cuff Repair Results in Persistent Muscle Atrophy and Fatty Infiltration

2018 ◽  
Vol 46 (12) ◽  
pp. 2981-2989 ◽  
Author(s):  
Zili Wang ◽  
Xuhui Liu ◽  
Michael R. Davies ◽  
Devante Horne ◽  
Hubert Kim ◽  
...  
Keyword(s):  
Rotator Cuff ◽  
Mouse Model ◽  
Mechanical Testing ◽  
Muscle Atrophy ◽  
Molecular Mechanisms ◽  
Ex Vivo ◽  
Fatty Infiltration ◽  
Shoulder Function ◽  
Muscle Weight ◽  
Orthopaedic Patients

Background: Rotator cuff (RC) tears are common tendon injuries seen in orthopaedic patients. Successful repair of large and massive RC tears remains a challenge due to our limited understanding of the pathophysiological features of this injury. Clinically relevant small animal models that can be used to study the pathophysiological response to repair are limited by the lack of chronic repair models. Purpose: To develop a highly clinically relevant mouse model of delayed RC repair. Study Design: Controlled laboratory study. Methods: Three-month-old C57BL/6J mice underwent unilateral supraspinatus (SS) and infraspinatus (IS) tendon tear with immediate, 2-week delayed, or 6-week delayed tendon repair. Animals with no repair or sham surgery served as controls. Gait analysis was conducted to measure shoulder function at 2 weeks and 6 weeks after surgery. Animals were sacrificed 6 weeks after the last surgery. Shoulder joint, SS, and IS muscles were harvested and analyzed histologically. Ex vivo mechanical testing of intact and repaired SS and IS tendons was conducted. Reverse-transcriptase polymerase chain reaction was performed on SS and IS muscles to quantify atrophy, fibrosis, and fatty infiltration–related gene expression. Results: Histological and tendon mechanical testing showed that torn tendons could be successfully repaired as late as 6 weeks after transection. However, significant atrophy and fatty infiltration of muscle, with impaired shoulder function, were persistent in the 6-week delayed repair group. Shoulder function correlated with the severity of RC muscle weight loss and fatty infiltration. Conclusion: We successfully developed a clinically relevant mouse model of delayed RC repair. Six-week delayed RC repair resulted in persistent muscle atrophy and fatty infiltration with inferior shoulder function compared with acute repair. Clinical Relevance: Our novel mouse model could serve as a powerful tool to understand the pathophysiological and cellular/molecular mechanisms of RC muscle and tendon degeneration, eventually improving our strategies for treating and repairing RC tears.

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