The Effect of Return to Overuse Activity After a Supraspinatus Tear on Joint Function and Biceps Mechanical Properties in a Rat Model

2011 ◽  
Author(s):  
Stephen J. Thomas ◽  
Joseph J. Sarver ◽  
Jennica Tucker ◽  
Katherine Reuther ◽  
Lena Edelstein ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Insertion Site ◽  
Supraspinatus Tendon ◽  
Shoulder Function ◽  
Shoulder Injuries ◽  
Tendon Tear ◽  
Model Studies ◽  
Cuff Tear ◽  
Supraspinatus Tear ◽  
Long Head

Rotator cuff tendon tears are one of the most common shoulder injuries and are most prevalent in populations performing repetitive overhead activities [1]. In addition, long head of the biceps (LHB) tendon injuries occur secondary to cuff tears and may or may not lead to functional deficits [2]. Previous animal model studies have found that in the presence of a cuff tear, the biceps has decreased mechanical properties at 8 weeks [3]. Such studies, however, did not examine the effect of repetitive overhead activity on biceps properties and shoulder function in the presence of a cuff tear. Therefore, the objective of this study was to evaluate the effect of returning to overuse activity after a supraspinatus tendon tear on shoulder function and biceps structural and mechanical properties. We hypothesized that overuse activity following a supraspinatus tendon tear would not alter shoulder function, when compared to cage activity, but would decrease biceps structural and mechanical properties, particularly at the insertion site.

Long Durations of Immobilization in the Rat Result in Enhanced Mechanical Properties of the Healing Supraspinatus Tendon Insertion Site

2006 ◽  
Vol 129 (3) ◽  
pp. 400-404 ◽  
Author(s):  
J. A. Gimbel ◽  
J. P. Van Kleunen ◽  
G. R. Williams ◽  
S. Thomopoulos ◽  
L. J. Soslowsky
Keyword(s):  
Mechanical Properties ◽  
Rotator Cuff ◽  
Bone Healing ◽  
Insertion Site ◽  
Supraspinatus Tendon ◽  
Shoulder Function ◽  
Activity Level ◽  
Rotator Cuff Tears ◽  
Operative Activity ◽  
Positive Effect

Rotator cuff tears frequently occur and can lead to pain and decreased shoulder function. Repair of the torn tendon back to bone is often successful in relieving pain, but failure of the repair commonly occurs. Post-operative activity level is an important treatment component that has received minimal attention for the shoulder, but may have the potential to enhance tendon to bone healing. The objective of this study was to investigate the effect of short and long durations of various activity levels on the healing supraspinatus tendon to bone insertion site. Rotator cuff tears were surgically created in Sprague–Dawley rats by detaching the supraspinatus tendon from its insertion on the humerus and these tears were immediately repaired back to the insertion site. The post-operative activity level was controlled through shoulder immobilization (IM), cage activity (CA), or moderate exercise (EX) for durations of 4 or 16 weeks. The healing tissue was evaluated utilizing biomechanical testing and a quantitative polarized light microscopy method. We found that activity level had no effect on the elastic properties (stiffness, modulus) of the insertion site at four weeks post injury and repair, and a decreased activity level had a positive effect on these properties at 16 weeks (IM>CA=EX). Furthermore, a decreased activity level had the greatest positive effect on these properties over time (IM>CA=EX). The angular deviation of the collagen, a measure of disorganization, was decreased with a decrease in activity level at 4 weeks (IM<CA=EX), but was similar between groups at 16 weeks (IM=CA=EX). It appears from this study that decreasing the activity level by immobilizing the shoulder improves tendon to bone healing, which progresses by first increasing the organization of the collagen and then increasing the mechanical properties. Future studies in this area will investigate the effect of passive motion and remobilization on both tendon to bone healing and shoulder function.

scholarly journals Pregnancy and Lactation Impair Subchondral Bone Leading to Reduced Rat Supraspinatus Tendon-to-Bone Insertion Site Failure Properties

2020 ◽  
Vol 142 (11) ◽  
Author(s):  
Ashley K. Fung ◽  
Snehal S. Shetye ◽  
Yihan Li ◽  
Yilu Zhou ◽  
X. Sherry Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Bone Loss ◽  
Subchondral Bone ◽  
Bone Mineralization ◽  
Insertion Site ◽  
Supraspinatus Tendon ◽  
Bone Microstructure ◽  
Female Rats ◽  
Pregnancy And Lactation ◽  
Failure Properties

Abstract Pregnant women experience weight gain, gait changes, and biochemical fluctuations that impair joint function and alter the maternal skeleton. Hormonal changes increase pelvic ligament laxity in preparation for childbirth and affect peripheral joint laxity. Calcium demands also rise during pregnancy and lactation, resulting in reduced bone mineral density (BMD) and maternal bone loss. Altered tendon properties and bone loss during pregnancy and lactation may impact tendon insertion sites, such as rotator cuff tendons where insertion site ruptures are common. However, the effects of pregnancy and lactation at the tendon-to-bone interface have not been investigated. Therefore, the objective of this study was to evaluate supraspinatus tendon mechanical properties and insertion site microstructure during pregnancy, lactation, and postweaning recovery in female rats. We hypothesized that pregnancy and lactation would compromise supraspinatus tendon mechanical properties and subchondral bone microstructure. Female rats were divided into virgin, pregnancy, lactation, and recovery groups, and supraspinatus tendons were mechanically evaluated. Surprisingly, tendon mechanics was unaffected by pregnancy and lactation. However, tendon modulus decreased two-weeks postweaning. Additionally, tendons failed by bony avulsion at the insertion site, and the lactation group exhibited reduced failure properties corresponding to decreased subchondral bone mineralization. Lactation also resulted in dramatic bone loss at the epiphysis, but trabecular bone microarchitecture recovered postweaning. In conclusion, lactation following pregnancy impaired trabecular bone microstructure and subchondral bone mineralization, leading to reduced supraspinatus tendon-to-bone insertion site failure properties. These findings will contribute toward understanding the pathogenesis of tendon-to-bone disorders.

Effect of Preconditioning on Collagen Fiber Recruitment: Inhomogeneous Properties of Rat Supraspinatus Tendon

2010 ◽  
Author(s):  
Kristin S. Miller ◽  
Lena Edelstein ◽  
Louis J. Soslowsky
Keyword(s):  
Mechanical Properties ◽  
Collagen Fiber ◽  
Insertion Site ◽  
Supraspinatus Tendon ◽  
Fiber Alignment ◽  
Rigorous Evaluation ◽  
Structural Alterations ◽  
Testing Protocol ◽  
Inhomogeneous Properties ◽  
Collagen Fiber Alignment

Cyclic preconditioning is a commonly accepted initial component of any tendon testing protocol. Preconditioning provides tendons with a consistent “history” and stress-strain results become repeatable allowing for rigorous evaluation and comparison. While it is widely accepted that preconditioning is important, changes that occur during preconditioning are not well understood. Micro-structural alterations, such as re-arrangement of collagen fibers, is one proposed mechanism of preconditioning [1,4]. However, this mechanism has not been examined. Therefore, the objective of this study is to locally measure: 1) fiber re-alignment during preconditioning, stress relaxation and tensile testing and 2) corresponding mechanical properties, to address mechanisms of preconditioning as well as tissue nonlinearity and inhomogeneity in the rat supraspinatus tendon. We hypothesize that 1) fiber re-alignment will be greatest in the toe region, but will also occur during preconditioning and 2) mechanical properties and initial collagen fiber alignment will be greater in the midsubstance location of the tendon compared to the tendon-to-bone insertion site.

Collagen Fiber Re-Alignment and Mechanical Properties in a Mouse Supraspinatus Tendon Model: Examining Changes With Age and Location

2012 ◽  
Author(s):  
Kristin S. Miller ◽  
Brianne K. Connizzo ◽  
Elizabeth Feeney ◽  
Louis J. Soslowsky
Keyword(s):  
Mechanical Properties ◽  
Collagen Fiber ◽  
Mechanical Load ◽  
Mechanical Test ◽  
Insertion Site ◽  
Supraspinatus Tendon ◽  
Tissue Response ◽  
Mechanical Stimuli ◽  
Fiber Alignment ◽  
Collagen Fiber Alignment

One postulated mechanism of tendon structural response to mechanical load is collagen fiber re-alignment. Recently, where collagen fiber re-alignment occurs during a tensile mechanical test has been shown to vary by tendon age and location in a postnatal developmental mouse supraspinatus tendon (SST) model [1]. It is thought that as the tendon matures and its collagen fibril network, collagen cross-links and collagen-matrix interactions develop, its ability to respond quickly to mechanical stimuli hastens [1]. Additionally, the insertion site and midsubstance of postnatal SST may develop differently and at different rates, providing a potential explanation for differences in fiber re-alignment behaviors at the insertion site and midsubstance at postnatal developmental time points [1]. However, collagen fiber re-alignment behavior, in response to mechanical load at a mature age and in comparison to developmental ages, have not been examined. Therefore, the objectives of this study are to locally measure: 1) fiber re-alignment during preconditioning and tensile mechanical testing and 2) to compare local differences in collagen fiber alignment and corresponding mechanical properties to address tissue response to mechanical load in the mature and postnatal developmental mouse SST. We hypothesize that 1) 90 day tendons will demonstrate the largest shift in fiber re-alignment during preconditioning, but will also re-align during the toe- and linear-regions. Additionally, we hypothesize that 2) mechanical properties and initial collagen fiber alignment will be greater in the midsubstance of the tendon compared to the tendon-to-bone insertion site at 90 days, 3) that mechanical properties will increase with age, and that 4) collagen fiber organization at the insertion site will decrease with age.

A Novel Acromion Radiological Classification and Its Clinical Application Study: Comparing Rockwood Tilt View with Arthroscopic Findings in 101 Shoulders

2020 ◽  
Vol 10 (5) ◽  
pp. 1184-1189
Author(s):  
Yingchun Zhu ◽  
Xuewen Jia ◽  
Zhanping Jin ◽  
Yunfeng Mi ◽  
Zheyang Wang ◽  
...  
Keyword(s):  
Rotator Cuff ◽  
Rotator Cuff Tear ◽  
Classification System ◽  
Supraspinatus Tendon ◽  
New Classification ◽  
Tendon Tear ◽  
Cuff Tear ◽  
Observer Reliability ◽  
Traditional Classification

Background: It is estimated that more than 25% of general population more than 60 years old experience rotator cuff tear, acromial impingement syndrome is one of the most common causes. Morphology of acromion is an important extrinsic factor in the development of rotator cuff tear. The traditional classification of the acromion by Bigliani et al. based on supraspinatus outlet view has been widely used, but due to the high requirements for patients to obtain true supraspinatus outlet view and the poor inter-observer reliability, it brings lots of limitations to the clinical use of this classification. In our clinical work, we have noticed that the formation of acromial anterolateral spur on Rockwood tilt view has some relationship to a rotator cuff tear. Objectives: To develop a new classification of acromion based on the subacromial impingement theory and the Rockwood tilt view. And explore the application value of the new classification in the diagnosis and treatment of rotator cuff tear. Methods: From January 2017 to December 2017, 101 cases of shoulder arthroscopic surgeries for impingement syndrome or rotator cuff tear were retrospectively analyzed. We developed a new classification of the acromion based on the Rockwood tilt view as type I flat acromion, type II bump acromion and type III impingement acromion. The status of the supraspinatus tendon was also recorded as no tear, partial-thickness tear, and full-thickness tear. We tested the inter-observer and intra-observer reliability of the new classification system (Kappa value) and analyzed the correlation between the acromion morphology and the rupture of the supraspinatus tendon. Results: In all 101 cases, the most common type was the impingement acromion with 46 patients (45.5%), followed by bump acromion in 37 patients (36.6%), and the flat acromion in 18 patients (17.8%). The inter-observer reliability of the new classification system was significantly better than that of the traditional classification (0.826 vs. 0.281). The incidence of supraspinatus tendon tear in the patients with impingement acromion was significantly higher than that of the other two types of acromion (ϰ2 = 50.316,P < 0.05). Conclusion: The Rockwood tilt view can well demonstrate the exact architecture of the anterolateral acromion spur. The new classification based on Rockwood tilt view has high reliability and good reproducibility. The type III impingement acromion correlates highly with the supraspinatus tendon tear. Level of evidence: Level II.

Returning to Overuse Activity Following a Combined Supraspinatus and Infraspinatus Tear Leads to Shoulder Joint Damage

2013 ◽  
Author(s):  
Katherine E. Reuther ◽  
Stephen J. Thomas ◽  
Jennica J. Tucker ◽  
Joseph J. Sarver ◽  
Chancellor F. Gray ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Articular Cartilage ◽  
Rotator Cuff ◽  
Joint Damage ◽  
Shoulder Function ◽  
Force Balance ◽  
Rotator Cuff Tears ◽  
Subscapularis Tendon ◽  
Supraspinatus Tear ◽  
Anterior Posterior

Rotator cuff tendon tears are common conditions which can lead to significant pain and dysfunction. Tears may progress over time from isolated supraspinatus tears to complete ruptures of both the supraspinatus and infraspinatus tendons, disrupting the anterior-posterior force balance provided by the subscapularis anteriorly and infraspinatus posteriorly (commonly referred to as a “force couple”) [1]. This disruption may lead to increased joint instability and result in altered glenohumeral translations which may cause damage to joint structures, such as articular cartilage and adjacent (intact) tendons. This is a particular concern for active individuals who are likely to continue high levels of overuse activity (e.g., laborers, athletes), despite the presence of rotator cuff tears. Previous studies have shown that returning to overuse activity following an isolated supraspinatus tear alters biceps and glenoid articular cartilage properties, but does not alter shoulder function or the adjacent intact subscapularis tendon [2]. However, the consequences associated with disrupting the anterior-posterior force balance (supraspinatus and infraspinatus tears) are not understood. Therefore, the objectives of this study were 1) to investigate the effect of returning to overuse activity following tears of both the supraspinatus and infraspinatus tendons on shoulder function and the remaining intact tendon and glenoid cartilage mechanical properties and 2) to begin to define the biologic mechanisms responsible for these changes. We hypothesized that overuse activity following two-tendon rotator cuff tears would H1) alter shoulder function and H2) lead to damage (indicated by inferior mechanical properties and increased production of degenerative factors, extracellular matrix, and cartilage markers) in the remaining intact tendons (including the biceps and upper and lower subscapularis tendons) and in the anterior-superior region of the glenoid articular cartilage as a result of the excessive joint loading due to overuse following the supraspinatus-infraspinatus tear.

Supraspinatus tendon organizational and mechanical properties in a chronic rotator cuff tear animal model

2004 ◽  
Vol 37 (5) ◽  
pp. 739-749 ◽  
Author(s):  
Jonathan A. Gimbel ◽  
Jonathan P. Van Kleunen ◽  
Samir Mehta ◽  
Stephanie M. Perry ◽  
Gerald R. Williams ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Animal Model ◽  
Rotator Cuff ◽  
Rotator Cuff Tear ◽  
Supraspinatus Tendon ◽  
Cuff Tear

scholarly journals Prevalence of rotator cuff diseases in adults older than 40 years in or near Chuncheon city, Korea

2020 ◽  
Vol 23 (3) ◽  
pp. 125-130
Author(s):  
Do-Young Kim ◽  
Jung-Taek Hwang ◽  
Sang-Soo Lee ◽  
Jun-Hyuck Lee ◽  
Min-Soo Cho
Keyword(s):  
Rotator Cuff ◽  
Rotator Cuff Tear ◽  
Shoulder Function ◽  
Elderly Persons ◽  
Rotator Cuff Disease ◽  
Analog Scale ◽  
Cuff Tear ◽  
High Prevalence ◽  
Routine Physical Examination ◽  
Long Head

Background: To determine the prevalence of rotator cuff diseases in a population older than 40 years in or nearby Chuncheon city, Republic of Korea.Methods: Sixty shoulders of 30 people older than 40 years who participated in a health lecture were examined for free by an orthopedic surgeon. Visual analog scale of pain and American Shoulder and Elbow Surgeons scores were assigned, and routine physical examination was performed. Ultrasonography was performed on the shoulder. Results: On ultrasonographic examination, there were one shoulder with full thickness rotator cuff tear, 20 of 60 (33%) with partial thickness rotator cuff tear, five of 60 (8%) with calcific tendinitis, one of 60 (2%) with tear of the long head of the biceps, and five of 50 (8%) with tendinitis of the long head of the biceps. Participants older than 60 years showed significantly high proportions of lesion of the long head of the biceps and rotator cuff diseases (P=0.019 and P=0.015, respectively). Participants who performed physical labor had high proportions of rotator cuff tear and rotator cuff disease (P=0.001 and P<0.001, respectively). Conclusions: Rotator cuff diseases showed a high prevalence in elderly persons and resulted in a decrease in shoulder function.

scholarly journals Shoulder Function and Fatty Infiltration on MRI in Older Adults During Rehabilitation for Rotator Cuff Tear

2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. 960-960
Author(s):  
Derik Davis ◽  
Ranyah Almardawi ◽  
Omer Awan ◽  
Lawrence Lo ◽  
Sagheer Ahmed ◽  
...  
Keyword(s):  
Older Adults ◽  
Rotator Cuff ◽  
Rotator Cuff Tear ◽  
Fatty Infiltration ◽  
Shoulder Function ◽  
Control Cohort ◽  
Cuff Tear ◽  
Supraspinatus Tear ◽  
Cohort Groups ◽  
Over Time

Abstract Rotator cuff tear is highly prevalent in older adults, with supraspinatus tendon tear (STT) the most common. Shoulder rehabilitation is a major treatment strategy, but supraspinatus-muscle-fatty infiltration (FI) and shoulder function in older adults with rotator cuff tear primarily managed by physical therapy (PT) is inadequately documented. We tested the hypothesis that older adults receiving usual-care PT when stratified by supraspinatus tear-status differ in supraspinatus FI [by quantitative Dixon fat fraction (FF) and semi-quantitative Goutallier grade (GG) on MRI] and shoulder function [by the American Shoulder and Elbow Surgeons score (ASES-score)] over time. Longitudinal cohort study (pilot): adults 60-85 years, PT-cohort (n=15) and control-cohort (n=25). Participants completed both shoulder MRI and ASES survey at baseline and follow-up visits. Kruskal-Wallis test compared within cohort among 3 groups: no tear (no-STT), partial-thickness tear (pt-STT), full-thickness tear (ft-STT). Mann-Whitney U test compared equivalent groups between cohorts. Baseline PT-cohort groups differed for GG (p=0.033) [no tear, 0.50±0.50;pt-STT, 1.11±0.22;ft-STT, 1.50±0.50] without difference in age, BMI, comorbidity, or ASES-score. Baseline control-cohort groups differed for FF (p=0.034) [no-tear, 5.77%±1.16%;pt-STT, 7.14%±6.26%;ft-STT, 21.44%±10.44%], without difference in age, BMI, comorbidity, or ASES-score. Baseline no-tear groups for ASES-score (p=0.049) differed between cohorts: PT-cohort (58.87±8.21) versus control-cohort (83.98±21.89). Both cohorts showed no difference in Δ-FF or Δ-GG over time. PT-cohort groups differed for Δ-ASES-score over time (p=0.042)[no-tear, 16.65±4.69;pt-STT, -7.24±0.94;ft-STT, 4.48±3.45], but control-cohort groups did not (p&gt;0.050). Our results suggest differences exist for supraspinatus FI and self-reported shoulder function among older adults receiving PT for rotator cuff tear when stratified by supraspinatus tear-status.

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