Role of tear size and tendon degeneration for development of pain in rat models of rotator cuff tear

BACKGROUND

Rotator cuff tear (RCT) is a frequent etiology of shoulder pain and disability; however, the triggers for the onset and aggravation of pain remain obscure. In this study, we established novel rat RCT models to examine the impact of tear size and tendon degeneration on pain.

METHODS

Fifty-five adult male Sprague-Dawley rats were allocated into 4 study groups: large tear (L group, n = 10), small tear (S group, n = 15), small tear with scratching (S+ group n = 15), and sham surgery (Sham group, n = 15). Pain-related behaviors were evaluated by weight distribution of forelimbs during a 5-minute free gait using a dynamic weight-bearing apparatus at 2, 4, 6, and 8 weeks. Calcitonin gene-related peptide (CGRP) expressions in ipsilateral dorsal root ganglion (DRG) neurons of C4, C5, and C6 were evaluated at 4 and 8 weeks. The area of scar tissues around the torn tendon, infiltration of inflammatory cells, and severity of tendon degeneration (modified Bonar score) were histologically assessed at 4 and 8 weeks. Additionally, enzyme-linked immunosorbent assay (ELISA) was conducted to evaluate the levels of cyclooxygenase-2 (COX-2) and nerve growth factor (NGF) expression in torn tendons and surrounding tissues at 4 weeks.

RESULTS

The weight distribution ratio (ipsilateral and contralateral side) was significantly decreased in the L and S+ group compared with its baseline and Sham group (P < .05), but the S group showed no significant difference compared with the Sham. The ratio of CGRP-immunoreactive neurons in the DRGs was significantly higher in the L and S+ groups than in the S and Sham groups. The histologic assessment indicated that scar tissue formation was more extensive in the L group than in the S and S+ groups. Still, there was no significant difference between the S and S+ groups. The modified Bonar score was considerably higher in the S+ group than in the S group. Furthermore, ELISA analysis demonstrated no significant disparity in COX-2 levels between the groups; however, NGF levels were substantially higher in the S+ group than in the S and Sham groups.

CONCLUSION

The present study provides compelling evidence that large RCT is strongly associated with heightened pain severity in a rat model. Nevertheless, even a small tear can significantly aggravate pain when the torn tendon is degenerated. CGRP upregulation driven by peripheral NGF possibly played a pivotal role in the genesis and exacerbation of pain in small RCT.

More severe supraspinatus tendon degeneration on the contralateral shoulders in patients treated for symptomatic rotator cuff tears compared to healthy controls: a quantitative MRI-based study

BACKGROUND

Patients treated for symptomatic rotator cuff tear (RCT) on one shoulder seem to have a higher prevalence of RCT on the contralateral shoulder.

PURPOSE

To compare the supraspinatus (SSP) tendon and RC muscle properties on the contralateral shoulder in patients after repair surgery to those healthy individuals using quantitative magnetic resonance imaging (MRI).

MATERIAL AND METHODS

A total of 23 patients treated for RCT (group A) and 23 healthy controls (group B) were recruited. Constant score, visual analog scale score (VAS), and MRI examinations were conducted. The SSP tendon structural status was graded based on the Zlatkin classification and quantified on ultrashort echo time (UTE)-T2* mapping images. Fatty degeneration of RC muscles was classified according to the Goutallier classification and quantified on T2 mapping.

RESULTS

The Constant and VAS scores were comparable between groups A and B (all P >0.05). No significant differences were observed in tendon structural status between the two groups (P >0.05). However, significant differences were established in UTE-T2* values of the SSP tendon on the distal subregion between groups A and B (16.4 ± 2.4 ms vs. 14.8 ± 1.2 ms; P = 0.01). Regarding muscle degeneration, no significant differences were displayed in T2 values and Goutallier classification of RC muscles (all P >0.05).

CONCLUSION

Patients with a treated RCT demonstrated inferior SSP tendon in the distal subregion on the contralateral shoulders one year postoperatively compared to that of healthy controls based on quantitative MRI data.

Factors associated with healing failure after early repair of acute, trauma-related rotator cuff tears

BACKGROUND

Healing failure after rotator cuff repair is a challenging problem. Acute, trauma-related tears are considered a separate entity and are often treated surgically. The aim of this study was to identify factors associated with healing failure in previously asymptomatic patients with trauma-related rotator cuff tears treated with early arthroscopic repair.

METHODS

This study included 62 consecutively recruited patients (23% women; median age, 61 years; age range, 42-75 years) with acute symptoms in a previously asymptomatic shoulder and a magnetic resonance imaging-verified full-thickness rotator cuff tear after shoulder trauma. All patients were offered, and underwent, early arthroscopic repair, during which a biopsy specimen was harvested from the supraspinatus tendon and analyzed for signs of degeneration. Of the patients, 57 (92%) completed 1-year follow-up and underwent assessment of repair integrity on magnetic resonance images according to the Sugaya classification. Risk factors for healing failure were investigated using a causal-relation diagram where age, body mass index, tendon degeneration (Bonar score), diabetes mellitus, fatty infiltration (FI), sex, smoking, tear location regarding integrity of the rotator cable, and tear size (number of ruptured tendons and tendon retraction) were included and analyzed.

RESULTS

Healing failure at 1 year was identified in 37% of patients (n = 21). A high degree of FI of the supraspinatus muscle (P = .01), a tear location including disruption of rotator cable integrity (P = .01), and old age (P = .03) were associated with healing failure. Tendon degeneration as determined by histopathology was not associated with healing failure at 1-year follow-up (P = .63).

CONCLUSION

Older age, increased FI of the supraspinatus muscle, and a tear including disruption of the rotator cable increased the risk of healing failure after early arthroscopic repair in patients with trauma-related full-thickness rotator cuff tears.

Investigation of the Tissue Degenerative Impact of Increased BMI in Achilles Tendon via Strain Elastography and Finite Element Analysis

BACKGROUND

This study is focused on establishing a relationship between poor muscle activity faced by obese individuals due to the change in stiffness of the intramuscular mass of the lower limb. This issue is also common among athletes and physically active teenagers.

OBJECTIVE

The study is aimed at a subject assessment diagnosis technique named as Strain Elastography (SE) to measure muscle strain. Further, Finite Element Modelling (FEM) technique is used to investigate the strain and/or deformations generated in the Achilles Tendon (AT) models, which were categorized according to their Body Mass Index (BMI) through computationally applied loadings.

METHODS

Total 54 volunteers with an average age of 21.85 ± 1.28 years were categorized into three groups according to their BMI (kg/m2); under BMI < 18.5 (n=14), normal BMI = 18.5-24.9 (n=20) and over BMI/obese > 25.0 (n=20). Additionally, multiple correlational analyses were performed between full range of BMI values and SE outcome.

RESULTS

The presence of significant difference (p<0.05) was measured between different categories for BMI, BFMI, FFMI, DLFC, tendon length, tendon thickness and SR. Moreover, multiple correlational analyses and scatter plot strengthen the results. For FEM simulations, the maximum deformation was observed at the proximal end of the tendon in all three groups.

CONCLUSION

It can be concluded that change in tendon stiffness and the resulting change in tendon structure was visualized with increased BMI. Moreover, obese individuals are more prone to tendon injury due to the increment in tendon thickness which causes bulging of the AT due to higher loads.

17β-Estradiol attenuates inflammation and tendon degeneration in a rat model of Achilles tendinitis

INTRODUCTION

17β-Estradiol (E2) is an immune-regulatory agent with anti-inflammatory effects. However, it is still unknown whether E2 exerts pharmacological properties against Achilles tendinitis (AT). This study aims to investigate the effects of E2 on AT and its underlying mechanisms.

MATERIALS AND METHODS

The established model of Achilles tendinitis was intraperitoneally injected with E2 (10, 20, or 30 μg/kg/d). After 8 weeks, biomechanical properties of the Achilles tendon were determined. Hydroxyproline content and tendon degeneration-related biomarkers were determined. The levels of inflammatory cytokines and apoptotic-related biomarkers in tendon tissues were determined. Furthermore, western blotting was determined to detect the expressions of ER-α and the PI3K/Akt pathway in tendon tissues.

RESULTS

E2 relieved AT-related symptoms in a dose-dependent manner. E2 ameliorated tendon degeneration by regulating tendon degeneration-related biomarkers (e.g., collagen type I and III, Decorin (DCN), and tenascin-C). Besides, treatment with E2 suppressed inflammatory cytokines and increased anti-inflammatory cytokines. Treatment with E2 also regulated cell apoptosis in tendon tissues. The underlying mechanism study revealed that treatment with E2 activated ER-α and upregulated the PI3K/Akt pathway.

CONCLUSION

The regulatory effects of E2 on inflammation and tendon degeneration in a rat model of AT were associated with the ER-α and the PI3K/Akt signaling pathways.

Cell autonomous TGFβ signaling is essential for stem/progenitor cell recruitment into degenerative tendons

Understanding cell recruitment in damaged tendons is critical for improvements in regenerative therapy. We recently reported that targeted disruption of transforming growth factor beta (TGFβ) type II receptor in the tendon cell lineage (Tgfbr2^ScxCre) resulted in resident tenocyte dedifferentiation and tendon deterioration in postnatal stages. Here we extend the analysis and identify direct recruitment of stem/progenitor cells into the degenerative mutant tendons. Cre-mediated lineage tracing indicates that these cells are not derived from tendon-ensheathing tissues or from a Scleraxis-expressing lineage, and they turned on tendon markers only upon entering the mutant tendons. Through immunohistochemistry and inducible gene deletion, we further find that the recruited cells originated from a Sox9-expressing lineage and their recruitment was dependent on cell autonomous TGFβ signaling. The cells identified in this study thus differ from previous reports of cell recruitment into injured tendons and suggest a critical role for TGFβ signaling in cell recruitment, providing insights that may support improvements in tendon repair.

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Targeted deletion of TGFβ signaling led to degenerative changes in mouse tendons

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Stem/progenitor cells were recruited into the degenerative mutant tendons

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The recruited cells are different from the ones so far reported in tendon injury

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Recruitment was dependent on cell autonomous TGFβ signaling in the recruited cells

Achilles tendon degeneration on ultrasound in type 2 diabetic patients

Aim of study

The main goal of this study was to compare the various degenerative changes in the Achilles tendon of type 2 diabetic patients to that of controls. The influence of diabetic peripheral neuropathy, duration of diabetes mellitus, age, and body mass index on the occurrence of degenerative changes was also evaluated.

Materials and methods

The Achilles tendons of both limbs were evaluated with high-resolution ultrasound in 80 type 2 diabetics and 80 age/sex-matched controls. A 10 g Semmes Weinstein monofilament was used to examine for peripheral neuropathy. Anthropometric measurements and biochemical assessment of glycemic control (fasting plasma glucose and glycated hemoglobin) were also done.

Results

The mean age of type 2 diabetic subjects and healthy controls was 60.9 ± 10.3 years (range 41–79 years) and 61.0 ± 10.3 years (range 40–79 years), respectively (p = 0.963). The median duration of diabetes mellitus was 42.0 months (range = 1–456 months). The prevalence of degenerative changes (calcifications, disorganized fibers and/or hypoechoic foci) was significantly higher in type 2 diabetic subjects than controls in both the right (55.0% vs. 18.8%, p <0.001) and left (52.5% vs. 18.8%, p <0.001) feet.

Conclusion

The Achilles tendons of type 2 diabetic subjects have significantly more degenerative changes than their age/sex-matched controls in our locality. Disorganized Achilles tendon fibers occur significantly more often among male than female type 2 diabetic subjects. Disorganization of Achilles tendon fibers and hypoechoic foci are significantly more prevalent in type 2 diabetic subjects with peripheral neuropathy than those without peripheral neuropathy. Body mass index did not affect the occurrence of degenerative changes in the Achilles tendon of participants.

Tgfβ signaling is critical for maintenance of the tendon cell fate

Studies of cell fate focus on specification, but little is known about maintenance of the differentiated state. In this study, we find that the mouse tendon cell fate requires continuous maintenance in vivo and identify an essential role for TGFβ signaling in maintenance of the tendon cell fate. To examine the role of TGFβ signaling in tenocyte function the TGFβ type II receptor (Tgfbr2) was targeted in the Scleraxis-expressing cell lineage using the ScxCre deletor. Tendon development was not disrupted in mutant embryos, but shortly after birth tenocytes lost differentiation markers and reverted to a more stem/progenitor state. Viral reintroduction of Tgfbr2 to mutants prevented and even rescued tenocyte dedifferentiation suggesting a continuous and cell autonomous role for TGFβ signaling in cell fate maintenance. These results uncover the critical importance of molecular pathways that maintain the differentiated cell fate and a key role for TGFβ signaling in these processes.

MicroRNA Profiling Reveals Distinct Signatures in Degenerative Rotator Cuff Pathologies

MicroRNAs (miRNAs) have emerged as key regulators orchestrating a wide range of inflammatory and fibrotic diseases. However, the role of miRNAs in degenerative shoulder joint disorders is poorly understood. The aim of this explorative case-control study was to identify pathology-related, circulating miRNAs in patients with chronic rotator cuff tendinopathy and degenerative rotator cuff tears (RCT). In 2017, 15 patients were prospectively enrolled and assigned to three groups based on the diagnosed pathology: (i) no shoulder pathology, (ii) chronic rotator cuff tendinopathy, and (iii) degenerative RCTs. In total, 14 patients were included. Venous blood samples ("liquid biopsies") were collected from each patient and serum levels of 187 miRNAs were determined. Subsequently, the change in expression of nine candidate miRNAs was verified in tendon biopsy samples, collected from patients who underwent arthroscopic shoulder surgery between 2015 and 2018. Overall, we identified several miRNAs to be progressively deregulated in sera from patients with either chronic rotator cuff tendinopathy or degenerative RCTs. Importantly, for the several of these miRNAs candidates repression was also evident in tendon biopsies harvested from patients who were treated for a supraspinatus tendon tear. As similar expression profiles were determined for tendon samples, the newly identified systemic miRNA signature has potential as novel diagnostic or prognostic biomarkers for degenerative rotator cuff pathologies. © 2019 The Authors. Journal of Orthopaedic Research^® published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society. Inc. J Orthop Res 38:202-211, 2020.

Risk Factors for Rotator Cuff Disease: An Experimental Study on Intact Human Subscapularis Tendons

Although several studies revealed a multifactorial pathogenesis of degenerative rotator cuff disorders, the impact and interaction of extrinsic variables is still poorly understood. Thus, this study aimed at uncovering the effect of patient- and pathology-specific risk factors that may contribute to degeneration of the rotator cuff tendons. Between 2015 and 2018, 54 patients who underwent arthroscopic shoulder surgery at three specialized shoulder clinics were prospectively included. Using tendon samples harvested from the macroscopically intact subscapularis (SSC) tendon, targeted messenger RNA expression profile analysis was performed in the first cohort (n = 38). Furthermore, histological analyses were conducted on tendon tissue samples obtained from a second cohort (n = 16). Overall, both study cohorts were comparable concerning patient demographics. Results were then analyzed with respect to specific extrinsic factors, such as patient age, body mass index, current as well as previous professions and sport activities, smoking habit, and systemic metabolic diseases. While patient age, sports-activity level, and preexisting rotator cuff lesions were considered to contribute most strongly to tendinopathogenesis, no further coherences were found. With regards to gene expression analysis, change in expression correlated most strongly with patient age and severity of the rotator cuff pathology. Further, chronic disorders increased overall gene expression variation. Taken together, our study provides further evidence that tendon degeneration is the consequence of a multifactorial process and pathological changes of the supraspinatus tendon affect the quality of SSC tendon and most likely vice versa. Therefore, the rotator cuff tendons need to be considered as a unit when managing rotator cuff pathologies. © 2019 The Authors. Journal of Orthopaedic Research^® published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society J Orthop Res 38:182-191, 2020.

Promoting effective tendon healing and remodeling

Daily activities subject our tendons to accumulation of sub-rupture fatigue injury which can lead to tendon rupture. Consequently, tendinopathies account for over 30% of musculoskeletal consultations. We adopted a multidisciplinary approach to determine the role of the extracellular matrix (ECM) in the pathogenesis of tendinopathy and impaired healing of ruptured tendons. We have been investigating three main areas: (i) the pathogenesis of tendon degeneration; (ii) approaches to promoting remodeling of sub-rupture fatigue injuries; and the (iii) role of the ECM in promoting scarless tendon healing. In this Kappa Delta Young Investigator award paper, we describe the key discoveries made in each of our three research areas of focus. Briefly, we discovered that sub-rupture fatigue damage can accumulate from just one bout of fatigue loading. Furthermore, any attempt to repair the fatigue damage diminishes as the severity of induced damage increases. We have utilized exercise to develop animal models of exercise-led degeneration and exercise-led repair of sub-rupture fatigue damage injuries, wherein underlying mechanisms can be uncovered, thereby overcoming a major hurdle to development of therapeutics. Since damage accumulation ultimately leads to rupture that is characterized by formation of a mechanically inferior scar, we have used the MRL/MpJ mouse to evaluate the role of the systemic environment and the local tendon environment in driving regeneration to identify new therapeutic pathways to promote scarless healing. Our data suggests that the therapeutic potential of the MRL/MpJ provisional ECM should be further explored as it may harness biological and structural mechanisms to promote scarless healing. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:3115-3124, 2018.

Fibrocartilaginous metaplasia identified in the long head of the biceps brachii

BACKGROUND

In the glenohumeral joint, the long head of biceps brachii (LHBB) is exposed to tension and compression loading. The short head of biceps brachii (SHBB) works only in tension. It is known that tendon under compression might develop fibrocartilaginous metaplasia that improves the resistance to compression but reduces the resistance to tension. This study evaluated the presence of cartilage in LHBB and SHBB samples, supporting its possible role in tendon tear.

METHODS

Between 2014 and 2016, 13 samples of LHBB and SHBB were collected during surgery for shoulder instability, glenohumeral arthritis, and massive rotator cuff tears. The samples were stained with hematoxylin and eosin, safranin-O, and Alcian blue (pH 1.0) for light microscopy. Immunohistochemistry was performed using anti-S100, anti-collagen I and II, and anti-tenascin-C antibodies.

RESULTS

Histochemistry: LHBB samples showed matrix disorganization, with clusters of chondrocyte surrounded by collagen fibers and glycosaminoglycans. Safranin-O showed evident metachromasia. SHBB samples did not show any matrix disorganization or cartilaginous metaplasia. Immunohistochemistry: In all LHBB samples, anti-S100 and anti-collagen II showed cartilage in proximity of the tendon tear. Tenascin C immunostained closely to the disorganized matrix areas. SHBB, however, showed no positive areas for S-100, anti-collagen II, or tenascin C.

CONCLUSIONS

According to our results, we hypothesize that the repeated stimulation in compression may induce the formation of fibrous cartilage. However, to date its role in tendon pathology remains to be clearly defined.

[Jumper's Knee]

Zusammenfassung. Sportliche Aktivitäten mit Sprungabläufen stellen für die Kniegelenke eine mechanische Herausforderung dar. Häufig projizieren sich chronisch auftretende, atraumatische Beschwerden auf den Patellaunterpol, welcher pathomorphologisch eine patellare Tendinopathie entspricht. Extrinsische und intrinsische Risikofaktoren können unterschieden werden. In der klinischen Untersuchung zeigt sich ein meist unauffälliges Knie mit einer Druckdolenz am kaudalen Teil der Kniescheibe beim Übergang zum Ligamentum patellae. In der Bildgebung ist sonografisch ein degenerierter Sehnenanteil der tiefen Patellarsehne zu erkennen, der magnettomografisch mit Hyperintensität des Hoffa-Körpers einhergehen kann. Abhängig von der klinischen Entwicklung wird das Jumper’s Knee nach Blazina Grad I–IV eingeteilt. Bis zu 90 % der Patienten können konservativ therapiert werden. Operativ stehen offene und arthroskopische Verfahren mit ordentlichem Resultat zur Verfügung.

Supraspinatus detachment causes musculotendinous degeneration and a reduction in bone mineral density at the enthesis in a rat model of chronic rotator cuff degeneration

BACKGROUND

To evaluate biological strategies that enhance tendon-bone healing in humans, it is imperative that suitable animal models accurately reproduce the pathological changes observed in the clinical setting following a tear. The purpose of the present study was to investigate rotator cuff degeneration in a rat, as well as assess the development of osteopenia at the enthesis following tendon detachment.

METHODS

Eighteen female Wistar rats underwent unilateral detachment of the supraspinatus tendon. Specimens were retrieved at 4 weeks (n = 6), 6 weeks (n = 6) and 9 weeks (n = 6) postoperatively for histological analysis and peripheral quantitative computer tomography.

RESULTS

Three weeks following tendon detachment, there was a significant increase in the modified Movin score, characterized by a loss of muscle mass, fatty infiltration, an increase in musculotendinous cellularity, loss of normal collagen fibre structure/arrangement, rounded tenocyte nuclei and an increase in the number of vascular bundles. This was accompanied by a reduction in bone mineral density at the tendon insertion site. After 3 weeks however, these changes were less prominent.

CONCLUSIONS

The rotator cuff tendon-muscle-bone unit in a rat model 3 weeks after detachment of supraspinatus represents a valid model for investigating rotator cuff degeneration.

Cellular and Molecular Factors Influencing Tendon Repair

Tendons are complex connective tissues that transmit tensile forces between muscles and tendons. Tendon injuries are among the most common orthopedic problems with long-term disability as a frequent consequence due to prolonged healing time. Furthermore, the repair tissue is of inferior quality, predisposing patients to high rates of recurrence following initial injury. Coordinated cellular processes and biological factors under the influence of mechanical loading are involved in tendon healing and our understanding of these events lags behind other musculoskeletal tissues. Tendons are relatively hypocellular and hypovascular, with little or no intrinsic regenerative capacity. Studies have documented fatty degeneration, chondrogenic dysplasia, and ectopic ossification within tendon repair tissue. The underlying pathogenesis for these metaplastic changes that compromise the quality of tendon repair tissue is poorly understood. The purpose of this review is to compile literature reporting molecular processes that regulate/control the phenotype of cells responsible for abnormal matrix deposition at repair site. In addition, recent studies reporting the interplay of mechanotransduction and cellular responses during tendon repair are summarized. Identifying the links between cellular, biological, and mechanical parameters involved in tendon repair is paramount to develop successful therapies for tendon healing.

Macroscopic and histologic evaluation of a rat model of chronic rotator cuff tear

BACKGROUND

The major cause of rotator cuff tears in humans is thought to be tendon degeneration. Although some studies have reported chronic rotator cuff tear models in animals, few studies of chronic rat models have demonstrated persistent defects for a relatively long time. The purpose of this study was to establish a chronic rotator cuff tear model in the rat and to evaluate the model macroscopically and histologically.

METHODS

Sixty Sprague Dawley rats were divided into 2 groups: tendon detachment only (tear group) and tendon detachment plus figure resin (chronic group). The contralateral shoulder served as a sham-operated control (sham group). In the tear group, the supraspinatus and infraspinatus tendons were completely detached. In addition to cuff detachment, figure resin was placed on the greater tuberosity to prevent cuff reattachment and scar formation in the chronic group. Macroscopic and histologic changes were assessed at 4 and 12 weeks after surgery.

RESULTS

A full-thickness cuff defect was observed in all chronic-group rats at both 4 and 12 weeks after surgery, and it could be repaired secondarily by traction in lower tension. However, no cuff defects were observed in the tear group because of obvious scar tissue formation. On histologic evaluation, progressive tendon degeneration, muscle atrophy, and fatty infiltration were observed in the chronic model at 12 weeks after surgery.

CONCLUSION

We established a rat model of chronic rotator cuff tears using figure resin. This chronic rotator cuff tear model might be useful for further clinical investigations of rotator cuff repair.

Biology and mechano-response of tendon cells: Progress overview and perspectives

In this review, we summarize the group discussions on Cell Biology & Mechanics from the 2014 ORS/ISMMS New Frontiers in Tendon Research Conference. The major discussion topics included: (1) the biology of tendon stem/progenitor cells (TSPCs) and the potential of stem cell-based tendon therapy using TSPCs and other types of stem cells, namely, embryonic and/or induced pluripotent stem cells (iPSCs), (2) the biological concept and potential impact of cellular senescence on tendon aging, tendon injury repair and the development of degenerative disease, and (3) the effects of tendon cells' mechano-response on tendon cell fate and metabolism. For each topic, a brief overview is presented which summarizes the major points discussed by the group participants. The focus of the discussions ranged from current research progress, challenges and opportunities, to future directions on these topics. In the preparation of this manuscript, authors consulted relevant references as a part of their efforts to present an accurate view on the topics discussed.

Operatively treated traumatic versus non-traumatic rotator cuff ruptures: a registry study

BACKGROUND

Operative treatment of traumatic rotator cuff ruptures, i.e. ruptures with a predisposing traumatic event, is reported to yield superior results compared to operative treatment of non-traumatic, degenerative ruptures.

AIM

The purpose of this study was to evaluate the difference of outcome, peroperative findings, and demographics after operative treatment of traumatic versus non-traumatic rotator cuff rupture.

METHODS

A total of 306 consecutive shoulders with an operated rotator cuff rupture (124 traumatic and 182 non-traumatic) were followed up. Constant and Murley score, size of the rupture, and age of the patients were used as an outcome measure.

RESULTS

A total of 112 traumatic and 167 non-traumatic rotator cuff rupture shoulders were available for 1-year follow-up (91%). Mean Constant and Murley score was preoperatively lower in the traumatic group (46 versus 52, P = 0.01). At 3 months postoperatively, Constant and Murley scores were 61 and 60 (P = 0.72) and at 1 year 73 and 77 (P = 0.03), respectively. Altogether 91% of the patients in the traumatic and 93% in the non-traumatic group were satisfied with the final outcome (P = 0.45). In 94% of traumatic and 95% of a non-traumatic cases the rupture involved the supraspinatus tendon. In the traumatic group the rupture was larger and involved more frequently the whole supraspinatus insertion area (41% versus 17%, P < 0.0001). Mean age of patients was 58 and 57 years, respectively.

CONCLUSION

Operative treatment of both traumatic and non-traumatic rotator cuff ruptures gives essentially good results. In our cohort, patients' recollection of predisposing trauma reflects the size of the rotator cuff rupture, but does not reflect the age of the patients.

Effect of angiogenesis-related cytokines on rotator cuff disease: the search for sensitive biomarkers of early tendon degeneration

BACKGROUND

Hallmarks of the pathogenesis of rotator cuff disease (RCD) include an abnormal immune response, angiogenesis, and altered variables of vascularity. Degenerative changes enhance production of pro-inflammatory, anti-inflammatory, and vascular angiogenesis-related cytokines (ARC) that play a pivotal role in the immune response to arthroscopic surgery and participate in the pathogenesis of RCD. The purpose of this study was to evaluate the ARC profile, ie, interleukin (IL): IL-1β, IL-6, IL-8, IL-10, vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and angiogenin (ANG), in human peripheral blood serum and correlate this with early degenerative changes in patients with RCD.

METHODS

Blood specimens were obtained from 200 patients with RCD and 200 patients seen in the orthopedic clinic for nonrotator cuff disorders. Angiogenesis imaging assays was performed using power Doppler ultrasound to evaluate variables of vascularity in the rotator cuff tendons. Expression of ARC was measured by commercial Bio-Plex Precision Pro Human Cytokine Assays.

RESULTS

Baseline concentrations of IL-1β, IL-8, and VEGF was significantly higher in RCD patients than in controls. Significantly higher serum VEGF levels were found in 85% of patients with RCD, and correlated with advanced stage of disease (r = 0.75; P < 0.0005), average microvascular density (r = 0.68, P < 0.005), and visual analog score (r = 0.75, P < 0.0002) in RCD patients. ANG and IL-10 levels were significantly lower in RCD patients versus controls. IL-1β and ANG levels were significantly correlated with degenerative tendon grade in RCD patients. No difference in IL-6 and bFGF levels was observed between RCD patients and controls. Patients with degenerative changes had markedly lower ANG levels compared with controls. Power Doppler ultrasound showed high blood vessel density in patients with tendon rupture.

CONCLUSION

The pathogenesis of RCD is associated with an imbalance between pro-inflammatory, anti-inflammatory, and vascular ARC.