Interleukin-1-induced subacromial synovitis and shoulder pain in rotator cuff diseases

The immune pathology of bursitis in rheumatic inflammatory diseases, degenerative conditions and mechanical stress: A systematic review

OBJECTIVE

To summarize current insights on the immune pathology of bursitis caused by rheumatic inflammatory diseases, degenerative conditions, or mechanical stress and identify knowledge gaps in this field. Data on tenosynovitis pathology was included for comparison.

METHODS

We performed a systematic review encompassing an electronic database search of all published literatures in PubMed/MEDLINE from inception to February 13, 2023, investigating the immunological changes occurring in the bursa of patients with inflammatory rheumatic diseases, degenerative conditions or mechanical stress (e.g., impingement syndrome).

RESULTS

Thirty-two articles provided data on the immune pathology of bursal tissue inflammation were identified. Histological and immunological perturbations included alterations of tissue morphology, infiltration of macrophages and some T cells, and enhanced expression of proinflammatory cytokines, such as interleukin (IL)-6, IL-1β and tumor necrosis factor alpha (TNF-α). These changes were described for all three underlying causes, although studies on bursitis associated with rheumatic inflammatory diseases were rare. Fibrosis was only reported in subacromial bursitis caused by mechanical stress within our included studies.

CONCLUSION

Current insights on bursitis were outdated and studies on bursitis associated with rheumatic inflammatory diseases are particularly lacking. Substantial overlap of enhanced expression of IL-6, IL-1β, TNF-α and infiltrating macrophages were found in bursitis irrespective of the underlying cause. In depth investigation on bursitis such as high throughput multi-omics are urgently needed to guide disease-specific therapeutic management.

The subacromial bursa modulates tendon healing after rotator cuff injury in rats

Rotator cuff injuries result in more than 500,000 surgeries annually in the United States, many of which fail. These surgeries typically involve repair of the injured tendon and removal of the subacromial bursa, a synovial-like tissue that sits between the rotator cuff and the acromion. The subacromial bursa has been implicated in rotator cuff pathogenesis and healing. Using proteomic profiling of bursa samples from nine patients with rotator cuff injury, we show that the bursa responds to injury in the underlying tendon. In a rat model of supraspinatus tenotomy, we evaluated the bursa's effect on the injured supraspinatus tendon, the uninjured infraspinatus tendon, and the underlying humeral head. The bursa protected the intact infraspinatus tendon adjacent to the injured supraspinatus tendon by maintaining its mechanical properties and protected the underlying humeral head by maintaining bone morphometry. The bursa promoted an inflammatory response in injured rat tendon, initiating expression of genes associated with wound healing, including Cox2 and Il6. These results were confirmed in rat bursa organ cultures. To evaluate the potential of the bursa as a therapeutic target, polymer microspheres loaded with dexamethasone were delivered to the intact bursae of rats after tenotomy. Dexamethasone released from the bursa reduced Il1b expression in injured rat supraspinatus tendon, suggesting that the bursa could be used for drug delivery to reduce inflammation in the healing tendon. Our findings indicate that the subacromial bursa contributes to healing in underlying tissues of the shoulder joint, suggesting that its removal during rotator cuff surgery should be reconsidered.

Blood flow velocity in the anterior humeral circumflex artery and tear size can predict synovitis severity in patients with rotator cuff tears

BACKGROUND

Rotator cuff tears are often associated with synovitis, but the ability of noninvasive ultrasonography to predict the severity of synovitis remains unclear. We investigated whether ultrasound parameters, namely peak systolic velocity in the anterior humeral circumflex artery and Doppler activity in the glenohumeral joint and subacromial space, reflect synovitis severity.

METHODS

A total of 54 patients undergoing arthroscopic rotator cuff repair were selected. Doppler ultrasound was used to measure peak systolic velocity in the anterior humeral circumflex artery and Doppler activity in the glenohumeral joint and subacromial space, and these values were compared with the intraoperative synovitis score in univariate and multivariate analyses.

RESULTS

Univariate analyses revealed that tear size, peak systolic velocity in the anterior humeral circumflex artery, and Doppler activity in the glenohumeral joint were associated with synovitis in the glenohumeral joint (P=0.02, P<0.001, P=0.02, respectively). In the subacromial space, tear size, peak systolic velocity in the anterior humeral circumflex artery, and Doppler activity in the subacromial space were associated with synovitis severity (P=0.02, P<0.001, P=0.02, respectively). Multivariate analyses indicated that tear size and peak systolic velocity in the anterior humeral circumflex artery were independently associated with synovitis scores in both the glenohumeral joint and the subacromial space (all P<0.05).

CONCLUSIONS

These findings demonstrate that tear size and peak systolic velocity in the anterior humeral circumflex artery, which can both be measured noninvasively, are useful indicators of synovitis severity. Level of evidence: IV.

Sensory innervation of the human shoulder joints in healthy and in chronic pain shoulder syndromes

BACKGROUND

Afferent innervation of shoulder joints plays a fundamental role in nociception and mechanoception and its alteration result in shoulder´s disease that course with pain and functional disability.

METHODS

Joints shoulder from healthy subjects (n = 20) and with chronic pain shoulder syndromes (n = 17) were analyzed using immunohistochemistry for S100 protein to identify nerve structures (nerve fibers and sensory corpuscles), coupled with a quantification of the sensory formations. Sensory nerve formations were quantified in 13 distinct areas in healthy joint shoulder and in the available equivalent areas in the pathological joints. Statistical analyses were conducted to assess differences between healthy shoulder and pathological shoulder joint (p< 0.05).

RESULTS

All analyzed structures, i.e., glenohumeral capsule, acromioclavicular capsule, the extraarticular structures (subcoracoid region and subacromio-subdeltoid bursa) and intraarticular structures (biceps brachii tendon and labrum articulare) are variably innervated except the extrinsic coracoacromial ligament, which was aneural. The afferent innervation of healthy human shoulder joints consists of free nerve endings, simple lamellar corpuscles and Ruffini's corpuscles. Occasionally, Golgi-Mazzoni's and Pacinian corpuscles were found. However, the relative density of each one varied among joints and/or the different zones within the same joint. As a rule, the upper half and anterior half of healthy glenohumeral capsules have a higher innervation compared to the lower and posterior respectably. On the other hand, in joints from subjects suffering chronic shoulder pain, a reduced innervation was found, involving more the corpuscles than free nerve endings.

CONCLUSIONS

Our findings report a global innervation map of the human shoulder joints, especially the glenohumeral one, and this knowledge might be of interest for arthroscopic surgeons allowing to develop more selective and unhurt treatments, controlling the pain, and avoiding the loss of afferent innervation after surgical procedures. To the light of our results the postero-inferior glenohumeral capsular region seems to be the more adequate to be a surgical portal (surgical access area) to prevent nerve lesions.

Clinical Implication of Glenohumeral and Subacromial Synovitis in Rotator Cuff Tears

Background

Synovitis of the glenohumeral (GH) joint and the subacromial (SA) space is commonly observed during arthroscopic rotator cuff surgery.

Purpose

To investigate the distribution, severity, and clinical implications of synovitis in the GH joint and SA space in patients with a full-thickness rotator cuff tear (RCT).

Study Design

Case series; Level of evidence, 4.

Methods

Data were retrospectively collected from 207 patients with a full-thickness RCT who underwent arthroscopic repair. Preoperative parameters used in the clinical assessment included pain, range of motion (ROM), muscle strength, and functional scores. Macroscopic assessment of synovitis was performed intraoperatively in the 3 regions of interest (ROIs) of the GH joint and 4 ROIS of the SA space using an evaluation system. The distribution and severity of synovitis and the association between synovitis and clinical assessment were evaluated.

Results

Synovitis was more severe in the GH joint than in the SA space (P < .001). Synovitis in the posterior GH joint and the lateral SA space, where most of the rotator cuff was located, was the most severe area among the ROIs of the GH joint and the SA space, respectively (P < .05). All types of pain, except for pain at rest, were associated with synovitis in the posterior GH joint (P < .05). All ROM measures were associated with synovitis in the posterior and inferior GH joint (|r| > 0.20; P < .05 for both). The strength of the supraspinatus and the infraspinatus was associated with synovitis in the posterior GH joint (P < .05). Shoulder function was associated with synovitis in the posterior and inferior GH joint and more in the posterior GH joint (P < .05 for both). Synovitis in the SA space was not associated with any of the clinical parameters.

Conclusion

Synovitis in the posterior GH joint was the most severe form of synovitis in the GH joint in patients with a full-thickness RCT. Synovitis in the posterior GH joint was closely associated with increased pain and decreased ROM, muscle strength, and functional score. Synovitis in the SA space was milder and not associated with any clinical parameters.

Comparison Clinical Effects of Hypertonic Dextrose and Steroid Injections on Chronic Subacromial Bursitis: A Double-Blind Randomized Controlled Trial

OBJECTIVE

The aim of the study is to determine and compare the treatment efficacy of subacromial steroid injections and dextrose prolotherapy for chronic subacromial bursitis patients.

DESIGN

Fifty-four patients with chronic subacromial bursitis were enrolled in this double-blind randomized controlled trial. Shoulder Pain and Disability Index and visual analog scale were the primary outcomes.

RESULTS

The steroid group ( n = 26) exhibited significant visual analog scale score improvements comparing with baseline at weeks 2, 6, and 12; the dextrose prolotherapy group ( n = 28) exhibited visual analog scale score improvements at weeks 6 and 12. The steroid group displayed significant Shoulder Pain and Disability Index score improvements compared with baseline at weeks 2, 6, and 12; the dextrose prolotherapy group exhibited significant score decreases at weeks 2 and 6. Compared with the dextrose prolotherapy group, the steroid group demonstrated significantly greater decreases in visual analog scale scores at weeks 2 and 6; the steroid group showed significantly greater decreases in Shoulder Pain and Disability Index scores at weeks 2, 6, and 12.

CONCLUSIONS

Both hypertonic dextrose prolotherapy and steroid injections can provide short-term improvements of pain and disability among chronic subacromial bursitis patients. Moreover, steroid injections showed better effectiveness than hypertonic dextrose prolotherapy in ameliorating pain and improving function.

Expression of Apelin in Rotator Cuff Tears and Examination of Its Regulatory Mechanism: A Translational Study

OBJECTIVES

Inflammatory mediators play important roles in the pain associated with rotator cuff tears (RCTs), but their underlying mechanisms are unclear. Apelin, a neuropeptide, is upregulated under inflammatory conditions and possibly contributes to pain induced by rotator cuff tears. This translational study aimed to examine apelin expression and regulation by tumor necrosis factor alpha (TNF-α) in patients with RCT and in rat RCT models.

METHODS

Synovial tissues were harvested from the glenohumeral joints of the shoulders in 46 patients who underwent arthroscopic Bankart repair for recurrent shoulder dislocations (RSDs) or arthroscopic rotator cuff repair for RCTs. The harvested tissues were extracted and processed by reverse transcriptase-polymerase chain reaction (RT-PCR). Rats underwent sham or RCT surgery; the rotator cuff tissues were extracted 1, 7, 14, 28, and 56 days after surgery and analyzed for mRNA expression levels of the TNF-α and apelin using RT-PCR. The cultured rotator cuff cells (RCCs) were stimulated with TNF-α to examine their role in the regulation of apelin expression.

RESULTS

Apelin expression was higher in the RCT group than in the RSD group and significantly correlated with pain intensity. In rats, the expression was also higher in RCT. Apelin expression significantly increased during the acute and chronic phases in rats.

CONCLUSIONS

In cultured RCCs, apelin mRNA levels significantly increased after TNF-α stimulation. Apelin levels were regulated by TNF-α and were highly expressed in patients with RCT and rats in RCT models. Thus, apelin may be a new pain management target for RCTs.

The subacromial bursa is a key regulator of the rotator cuff and a new therapeutic target for improving repair

Rotator cuff injuries result in over 500,000 surgeries performed annually, an alarmingly high number of which fail. These procedures typically involve repair of the injured tendon and removal of the subacromial bursa. However, recent identification of a resident population of mesenchymal stem cells and inflammatory responsiveness of the bursa to tendinopathy indicate an unexplored biological role of the bursa in the context of rotator cuff disease. Therefore, we aimed to understand the clinical relevance of bursa-tendon crosstalk, characterize the biologic role of the bursa within the shoulder, and test the therapeutic potential for targeting the bursa. Proteomic profiling of patient bursa and tendon samples demonstrated that the bursa is activated by tendon injury. Using a rat to model rotator cuff injury and repair, tenotomy-activated bursa protected the intact tendon adjacent to the injured tendon and maintained the morphology of the underlying bone. The bursa also promoted an early inflammatory response in the injured tendon, initiating key players in wound healing. In vivo results were supported by targeted organ culture studies of the bursa. To examine the potential to therapeutically target the bursa, dexamethasone was delivered to the bursa, prompting a shift in cellular signaling towards resolution of inflammation in the healing tendon. In conclusion, contrary to current clinical practice, the bursa should be retained to the greatest extent possible and provides a new therapeutically target for improving tendon healing outcomes.

One Sentence Summary

The subacromial bursa is activated by rotator cuff injury and regulates the paracrine environment of the shoulder to maintain the properties of the underlying tendon and bone.

Present situation and development prospects of the diagnosis and treatment of rotator cuff tears

Rotator cuff tears are an important cause of shoulder pain and are caused by degeneration or trauma of the shoulder tendon at the anatomical neck of the humeral head. The understanding and research of rotator cuff tears have a history of hundreds of years, and their etiology, diagnosis, and treatment have a complete system, but some detailed rules of diagnosis and treatment still have room for development. This research paper briefly introduces the diagnosis and treatment of rotator cuff tears. The current situation and its valuable research direction are described.

Biomolecules Related to Rotator Cuff Pain: A Scoping Review

The pathophysiology of pain in patients suffering from rotator cuff (RC) tendinopathy or tears has been examined in various ways. Several molecules from tissue samples taken from the subacromial bursa, supraspinatus tendon, glenohumeral joint fluid, and synovium as well as from peripheral blood have been investigated. This article explores these studies, the assessed biomarkers, and groups their results according to the status of tendon integrity (tendinopathy or tear). Through a structured PubMed database search, 9 out of 658 articles were reviewed. Interleukins, mostly IL-1b and its antagonist, IL-1ra, matrix Metalloproteinases (MMPs), the vascular endothelial growth factor (VEGF) and TNF-a are biomarkers directly searched for correlation to pain level. Most studies agree that IL-1b is directly positively correlated to the degree of pain in patients with RC tendinopathy, especially when the examined sample is taken from the subacromial bursa. VEGF, and TNF-a have been related to shoulder pain preoperatively and TNF-a has also been linked with sleep disturbance. Further studies pointing to more biomarkers taken from the subacromial bursa or tendon directly relating to pain degree are warranted.

Macroscopic aspects of glenohumeral synovitis are related to rotator cuff tear severity

BACKGROUND

The microscopic pattern of inflammatory mediators associated with rotator cuff pathology is well documented; however, little is known regarding the contemporary presence of macroscopic inflammatory joint involvement. Our aim was to investigate shoulder synovitis in a large group of patients with different sized rotator cuff tears (RCTs) and to correlate the degree of macroscopic inflammatory changes of the glenohumeral joint with RCT severity.

MATERIALS AND METHODS

A total of 296 consecutive patients (169 F, 127 M; mean age ± standard deviation: 60.75 ± 7.91) submitted to arthroscopic RCT repair were enrolled. RCT was classified intraoperatively. Glenohumeral synovitis was investigated according to 4 parameters (Davis classification 2017: capsule color, villous projections, capillaries, and axillary recess). A total score was calculated, and a 3-grade severity scale was introduced. Statistics was performed.

RESULTS

Intraclass correlation coefficient (ICC) results show good to excellent reliability: capsule color (ICC: 0.95; 95% confidence interval [CI]: 0.89-0.99), villous projections (ICC: 0.90; 95% CI: 0.85-0.95), capillaries (ICC: 0.91; 95% CI: 0.86-0.95), and axillary recess (ICC: 0.55; 95% CI: 0.80-0.89).The synovitis total score was found to be 1.47 ± 1.16, 2.86 ± 1.84, and 3.99 ± 1.64 in patients with type I, II, and III RCTs, respectively. A significant difference was found between groups (P < .001). The prevalence of all the examined parameters was found to be significantly different between the different sized RCT groups (capsule color: P < .001; villous projections: P < .001; capillaries: P < .001; and axillary recess: P < .001). According to a 3-grade severity scale, the prevalence of absent, mild, and severe glenohumeral synovitis significantly differed between the RCT severity groups (P < .001).

CONCLUSIONS

The present study demonstrated that synovitis is a constant finding of rotator cuff pathology; it is present in 75% of patients with RCTs and correlates with tear severity. Whether synovitis is the cause or effect of RCT is still questionable. Further studies are also needed to better understand its role as a pain generator, as documented in other diseases.

Incidence and risk factors for early postoperative stiffness after arthroscopic rotator cuff repair in patients without preoperative stiffness

The purpose of this study was to investigate the incidence and risk factors of early postoperative stiffness in patients without preoperative stiffness undergoing isolated arthroscopic rotator cuff repair (ARCR). Two hundred seventy-four patients who underwent primary ARCR were included. At 3 months after surgery, criteria for shoulder stiffness was set as follows: (1) passive forward flexion < 120˚, or (2) external rotation at side < 30˚. Patients with preoperative stiffness or who underwent additional procedures were excluded. Patients-related, radiological (muscle atrophy and fatty infiltration), and intraoperative (tear size, repair techniques, number of anchors used, and synovitis scores) risk factors were analyzed. Univariate and multivariate analyses were used to identify risk factors for postoperative stiffness. Thirty-nine of 274 patients (14.2%) who underwent ARCR developed postoperative stiffness. Univariate analyses revealed that early postoperative stiffness was significantly associated with diabetes mellitus (p = 0.030). However, radiological and intraoperative factors did not affect postoperative shoulder stiffness (all p > 0.05). Multivariate analyses revealed early postoperative stiffness was significantly associated with diabetes mellitus and timing of rehabilitation (p = 0.024, p = 0.033, respectively). The overall incidence of early postoperative stiffness following isolated ARCR in patients without preoperative stiffness was 14.2%. Diabetes mellitus and timing of rehabilitation were independent risk factors for early postoperative stiffness following ARCR.

Histological and molecular features of the subacromial bursa of rotator cuff tears compared to non-tendon defects: a pilot study

Background

The role of the subacromial bursa in the development or healing of shoulder pathologies is unclear. Due to this limited knowledge, we aimed to understand specific reactions of the subacromial bursa according to rotator cuff (RC) pathologies compared to non-tendon defects of the shoulder. We hypothesized that the tissue composition and inflammatory status of the bursa are likely to vary between shoulder pathologies depending on the presence and the extent of RC lesion.

Method

Bursa samples from patients with either 1) shoulder instability with intact RC (healthy bursa, control), 2) osteochondral pathology with intact RC, 3) partial supraspinatus (SSP) tendon tear, or 4) full-thickness SSP tear were investigated histologically and on gene expression level.

Result

Bursae from SSP tears differed from non-tendon pathologies by exhibiting increased chondral metaplasia and TGFβ1 expression. MMP1 was not expressed in healthy bursa controls, but strongly increased with full-thickness SSP tears. Additionally, the expression of the inflammatory mediators IL1β, IL6, and COX2 increased with the extent of SSP tear as shown by correlation analysis. In contrast, increased angiogenesis and nerve fibers as well as significantly upregulated IL6 and COX2 expression were features of bursae from patients with osteochondral pathology. Using immunohistochemistry, CD45+ leukocytes were observed in all examined groups, which were identified in particular as CD68+ monocytes/macrophages.

Conclusion

In summary, besides the strong increase in MMP1 expression with SSP tear, molecular changes were minor between the investigated groups. However, expression of pro-inflammatory cytokines correlated with the severity of the SSP tear. Most pronounced tissue alterations occurred for the osteochondral pathology and full-thickness SSP tear group, which demonstrates that the bursal reaction is not exclusively dependent on the occurrence of an SSP tear rather than longstanding degenerative changes. The present bursa characterization contributes to the understanding of specific tissue alterations related to RC tears or non-tendon shoulder pathologies. This pilot study provides the basis for future studies elucidating the role of the subacromial bursa in the development or healing of shoulder pathologies.

Perioperative Intravenous Lidocaine Infusion on Postoperative Recovery in Patients Undergoing Arthroscopic Rotator Cuff Repair Under General Anesthesia - A Randomized Controlled Trial

OBJECTIVE

Arthroscopic rotator cuff repair (ARCR) is known to cause severe postoperative pain which may interfere with recovery. Intravenous (IV) lidocaine has analgesic, anti-inflammatory, and anti-hyperalgesic effects, and is being used in various types of surgeries. However, the effect of IV lidocaine in ARCR is not well known.

MATERIALS AND METHODS

Ninety patients undergoing ARCR were randomly allocated to receive IV lidocaine (1.5▒mg/kg bolus of 1% lidocaine after anesthesia induction followed by a continuous infusion of 2▒mg/kg/h up to 1▒h after surgery) or an equal volume of saline. In both groups, an IV patient-controlled analgesia (PCA) device was used which contained fentanyl 10▒µg/mL, infused at 1▒mL/h with a 1▒mL bolus dose. The primary outcome was fentanyl requirements given via IV PCA during the first 24 hours after surgery. Perioperative pain scores and functional recovery were assessed as secondary outcomes.

RESULTS

The amount of fentanyl administered via IV PCA up to 24 hours after surgery was significantly lower in the Lidocaine group compared to the Control group (329 [256.2-428.3] vs. 394.5 [287.0-473.0], P=0.037) The number of PCA bolus attempts were lower in the Lidocaine group without statistical significance. There were no differences in postoperative pain scores or functional shoulder scores between the two groups.

DISCUSSION

IV lidocaine appears to be helpful in reducing opioid requirements during the acute postoperative period in patients undergoing ARCR. IV lidocaine may be a viable option as a component of multimodal analgesia in ARCR when regional analgesia is not possible.

Chronicity is associated with the glenohumeral synovitis in patients with a rotator cuff tear

Synovitis of the glenohumeral joint (GHJ) and subacromial space (SAS) is one of the most common findings during arthroscopic rotator cuff repair (RCR). The purpose of this study is to determine clinical factors associated with the degree of synovitis in patients with a rotator cuff tear and whether macroscopic synovitis affects early clinical outcomes following arthroscopic RCR. Arthroscopic videos of 230 patients treated with arthroscopic RCR were randomly reviewed by two experienced shoulder surgeons. The synovitis scores of the GHJ using Davis's grading system and the SAS using Jo's grading system were rated with a consensus. Univariate and multivariate analyses were used to identify the associations between the synovitis scores and various parameters, including demographics, preoperative, and postoperative clinical outcomes. Univariate analyses revealed that age, side, body mass index, duration of symptoms, preoperative stiffness, diabetes, muscle atrophy, fatty infiltration, tear size, preoperative clinical scores, and preoperative range of motion were significantly associated with the GHJ synovitis score (all p < 0.05). Multivariate analyses revealed that the duration of symptoms, tear size, and diabetes was significantly associated with the GHJ synovitis score (p = 0.048, p = 0.025, p = 0.011, respectively). Longer duration of symptoms, larger tear size, and the presence of diabetes was independently associated with increased GHJ synovitis in patients with a rotator cuff tear. These results suggest that GHJ synovitis might be more involved in the pathogenesis for pain and tear progression of rotator cuff disease compared with SAS synovitis.

It Is Time to Put Special Tests for Rotator Cuff-Related Shoulder Pain out to Pasture

"Special tests" for rotator cuff-related shoulder pain (RCRSP) have passed their sell-by date. In this Viewpoint, we outline fundamental flaws in the validity of these tests and their proposed ability to accurately identify a pathoanatomical source of pain. The potential harm of these special tests comes in conjunction with imaging findings that are utilized to inform a structural diagnosis or recommend invasive procedures. We offer recommendations for performing a clinical interview and physical examination for people with RCRSP that does not include shoulder orthopaedic tests. J Orthop Sports Phys Ther 2020;50(5):222-225. doi:10.2519/jospt.2020.0606.

Glenohumeral synovitis score predicts early shoulder stiffness following arthroscopic rotator cuff repair

Background

This study was conducted to determine if there is an association between an intraoperative glenohumeral synovitis score (GHSS) and postoperative shoulder stiffness in patients undergoing arthroscopic rotator cuff repair (ARCR).

Methods

Intraoperative GHSS was collected retrospectively from standardized arthroscopic images on consecutive patients undergoing primary ARCR. Range of motion was collected preoperatively and postoperatively at 3 and 6 months.

Results

290 consecutive patients underwent primary ARCR. At three-months follow-up, 32 (11.0%) patients had glenohumeral stiffness. Patients with stiffness had significantly higher mean GHSS.

Conclusion

Higher intraoperative GHSS was associated with early postoperative shoulder stiffness at three-months after ARCR.

Metabolic and inflammatory links to rotator cuff tear in hand osteoarthritis: A cross sectional study

Objectives

To estimate the prevalence and associated factors of rotator cuff tear (RCT) in patients with hand osteoarthritis (HOA).

Methods

Between June 2013 and December 2015, we recruited 1150 participants in rural area of South Korea. Of the 1150 participants, 307 participants with HOA were analyzed. Plain radiography of both hands, magnetic resonance imaging of both shoulders, and serum levels of high-sensitive C-reactive protein (hsCRP) and high-density lipoprotein (HDL) were obtained for all patients. HOA and RCT were diagnosed by clinical and radiologic findings.

Results

The prevalence of RCT in patients with HOA (192/307, 62.5%) was higher than that in those without HOA (410/827, 49.5%, p<0.001). Among the 307 patients with HOA, the patients with RCT were older, and had higher hsCRP and lower HDL levels than the patients without RCT. Multiple logistic regression analysis confirmed significant associations of age (odds ratio [OR], 1.06; 95% confidence interval [CI], 1.02–1.11), serum hsCRP levels ≥0.6mg/L (OR, 1.68; CI, 1.00–2.80), and low HDL levels (male, <50 mg/dL; female, <40 mg/dL) (OR, 1.93; CI, 1.05–3.56) with RCT in patients with HOA. For patients below 60 years old, the prevalence of RCT was 2.8-fold higher in the low HDL group than normal HDL group (p = 0.048). Finally, the prevalence of RCT was 2.6-fold higher in patients with HOA with both elevated hsCRP and low HDL levels compared with those with neither (p<0.05).

Conclusions

Our findings suggest inflammation and metabolic factors were associated with the prevalence of RCT in HOA patients.

IL-1β mediates NGF and COX-2 expression through transforming growth factor-activating kinase 1 in subacromial bursa cells derived from rotator cuff tear patients

BACKGROUND

Increased interleukin (IL)-1β expression in the subacromial bursa (SAB) is associated with severe pain in rotator cuff tears (RCTs). Additionally, transforming growth factor (TGF)-β-activated kinase 1 (TAK1) is essential for cytokine-mediated cascades. TAK1 also regulates the expression of pain-associated molecules such as cycloxygenase-2 (COX-2) and nerve growth factor (NGF) in synovial fibroblasts; however, this regulation in the SAB is not fully understood.

METHODS

SAB samples were harvested from 18 subjects with RCTs. The expression and localization of NGF and COX-2 was determined using polymerase chain reaction (PCR) analysis and immunohistochemistry. Regulation of COX-2 and NGF by IL-1β in subacromial bursa cells (SABCs) was investigated by culturing and stimulating SABCs with vehicle control (culture medium), 50 ng/ml recombinant human IL-1β (rhIL1-β), 50 ng/ml rhIL-1β and 10 μM celecoxib (COX-2 inhibitor), or 10 μM prostaglandin E2 (PGE2) for 24 h. The effects of TAK1 inhibition on rhIL-1β stimulation were determined by culturing and treating SABCs with control, 50 ng/ml rhIL-1β, or 50 ng/ml rhIL-1β and 10 μM (5Z)-7-oxozeaenol (TAK1 inhibitor) for 24 h. NGF and COX-2 mRNA expression was monitored using quantitative PCR.

RESULTS

COX-2 and NGF mRNA expression was observed in all SAB specimens. Immunohistochemical analysis showed that COX-2-positive cells were in the lining and sublining layers. NGF-positive cells were observed in the sublining layer. rhIL-1β treatment significantly increased NGF and COX-2 mRNA levels compared with control cells. The COX-2 inhibitor did not suppress rhIL-1β-induced NGF expression, and PGE2 stimulation did not alter NGF mRNA expression. In contrast, the TAK1 inhibitor significantly reduced rhIL-1β-stimulated COX-2 and NGF mRNA expression.

CONCLUSION

IL-1β regulates the expression of NGF and COX-2, pain-related molecules in the SAB, through TAK1. Therefore, TAK1 may be one potential therapeutic target for reducing pain in patients with RCTs.

Synovitis as a concomitant disease in shoulder pathologies

INTRODUCTION

Shoulder pathologies are often accompanied by rotator interval synovitis. This phenomenon is poorly described in the literature so far. The aim of the study was to analyze the occurrence of macroscopically visible synovial reaction in the rotator interval in patients with chronic shoulder pathologies and to perform a histopathological evaluation.

MATERIALS AND METHODS

In this prospective cohort study, 167 consecutive patients undergoing arthroscopic shoulder surgery for chronic shoulder pathology were included (♀ = 45, ♂ = 122; [Formula: see text]54.5 years ± 12.8). Included patients were divided into subgroups according to the encountered chronic shoulder pathology: (1) impingement syndrome with or without bursal sided partial rotator cuff tear (RCT); (2) articular sided partial RCT; (3) full-thickness RCT; (4) RCT that involves at least two tendons; (5) shoulder instability; and (6) cartilage damage. Standardized soft tissue biopsies from the rotator interval were taken. The synovitis score of Krenn/Morawietz was used for histopathological examination.

RESULTS

Extraarticular pathology (group 1) showed significantly decreased synovitis scores compared to all the other groups. Increased size of rotator cuff tears (group 4), as well as cartilage damage (group 6) showed significantly higher synovitis scores than group 3 (p < 0.05). Moreover, the synovitis score was significantly increased in patients with concomitant pathologies of the long head of the biceps (p = 0.001).

CONCLUSIONS

This study suggests that chronic intra- and extraarticular shoulder diseases are very often accompanied by a histopathologically verifiable low-grade synovitis. Intraarticular pathologies seem to induce increased levels of synovitis. Furthermore, the increased size of rotator cuff tears is accompanied by a higher degree of synovitis.

STUDY DESIGN

Cohort study, level of evidence, 2b.

Allogenic Pure Platelet-Rich Plasma Therapy for Rotator Cuff Disease: A Bench and Bed Study

BACKGROUND

Although platelet-rich plasma (PRP) is a popular option for rotator cuff disease, the underlying mechanism of PRP and its clinical indications are unclear. Further, some kinds of PRP might be detrimental to patients. Allogenic PRP prepared through a standardized process and fully characterized could eliminate variations in PRP as well as uncertainties regarding its use in each patient, which could provide clues about its mechanism of action and indications for its use.

PURPOSE

To assess the effects of pure PRP on tenocytes with or without inflammation in an in vitro study and to evaluate the safety and efficacy of a fully characterized pure PRP injection in patients with rotator cuff disease in a clinical study.

STUDY DESIGN

Controlled laboratory study and cohort study; Level of evidence, 3.

METHODS

For the in vitro study, tenocytes were enzymatically isolated and cultured from patients with rotator cuff tear and treated with or without interleukin 1β (IL-1β) and PRP. Gene expression and protein synthesis of pro- and anti-inflammatory cytokines, enzymes and their inhibitors, matrix synthesis, and cell viability were evaluated. For the clinical study, a total of 17 patients with rotator cuff disease received ultrasonography-guided subacromial PRP injection and were followed for 6 months. Pain, range of motion, muscle strength, shoulder function, and overall satisfaction in patients were compared with the results in a propensity score-matched control group who received corticosteroid (triamcinolone acetonide 40 mg).

RESULTS

PRP induced inflammation in the absence of inflammation and ameliorated inflammation in IL-1β-induced tendinopathic conditions by regulation of cytokines such as IL-1β, cyclooxygenase 2, microsomal prostaglandin E synthase 1, vasoactive intestinal peptide, and downstream matrix metalloproteinases. No general or local adverse events were noted with regard to allogenic PRP injection. Whereas steroid injection showed earlier improvement in some kinds of pain and functional scores, PRP generally showed comparable effects with steroid injection in all clinical outcomes at 6 months.

CONCLUSION

This study showed that allogenic pure PRP had pleiotropic effects on tenocytes depending on inflammation and that it did not cause adverse events but rather decreased pain and improved shoulder function to a degree comparable with steroid injection in patients with rotator cuff disease.

CLINICAL RELEVANCE

Allogenic PRP could be a treatment option for rotator cuff disease.

Classifying glenohumeral synovitis: a novel intraoperative scoring system

BACKGROUND

Synovitis of the shoulder is a common entity that is poorly described. This study aims to create a simple and reliable classification system for glenohumeral synovitis, which would benefit further research related to synovitis and outcomes.

METHODS

Twenty 30-second shoulder arthroscopy videos were distributed to 19 fellowship-trained orthopedic surgeons. The observers responded with their years in practice, fellowship type, whether synovitis affects outcomes, and whether synovitis affects plans. The surgeons then rated the videos based on the following: color of capsule (pale, pink, or red); villous projections (none, few, or extensive); capillaries in capsule (scattered or hypertrophied); and axillary recess (normal or contracted). Scores ranging from 0 to 6 were assigned. The videos were randomized and redistributed at a later date. Statistical analysis used an intraclass correlation coefficient with a mixed-effects model to calculate variability based on observer.

RESULTS

Nineteen observers completing the survey twice resulted in 760 videos being scored. There were 12 shoulder surgeons and 7 sports surgeons. Only 4 surgeons believed that synovitis did not affect outcomes, and the remaining 15 believed that it did. The intraclass correlation coefficient showed that 68% of the variation in measured scores was due to variation among patients and only 4% was due to variation among observers. There was no significant variation seen in scores due to surgeon experience, surgeon specialty, or first and second viewing.

CONCLUSIONS

This interclass observer reliability shoulder synovitis study defined a system with excellent reliability among a range of surgeons with diverse training and experience. In addition, there was excellent reliability for the same surgeon between viewings.

Growth factor expression after supraspinatus tear: a quantitative polymerase chain reaction (PCR) study in rats

INTRODUCTION

The objective of this study was to evaluate the temporal expression pattern of three different growth factors (VEGF, IL-1β, and TGF-1β) in a supraspinatus tendon lesion in an animal model. The hypothesis of this study is that there are variations in the expression of these factors in the first 8 weeks after injury.

MATERIALS AND METHODS

A full thickness defect was made in the supraspinatus tendon of 40 rat shoulders. The animal were sacrificed at 0, 3, 7, 14 and 56 days after injury and three tissue samples were obtained: bone from the tendon footprint; the supraspinatus tendon stump, and a fragment of the myotendinous junction. After mRNA extraction, quantitative PCR analysis was performed, and the expression of three different growth factors were evaluated in each zone.

RESULTS

There was an increased expression of IL-1β during the first week after injury at all levels evaluated with a clear peak in the first day after injury. There was also a significant increase in TGF-1β expression levels all along the first week in the three zones. There were no variations in VEGF expression in the three zones along the 8 weeks.

CONCLUSION

IL-1β was expressed predominantly in the initial stages after injury; TGF initiated its expression after the initial phase since day three, whereas VEGF remained basically unchanged during the entire process.

Macroscopic and microscopic assessments of the glenohumeral and subacromial synovitis in rotator cuff disease

Background

Whereas synovitis is one of most common findings during arthroscopic surgery in patients with rotator cuff diseases, no study has investigated its characteristics. We propose a macroscopic assessment system for investigating the characteristics of synovitis.

Methods

Fifty-four patients with a full-thickness rotator cuff tear undergoing arthroscopic rotator cuff repair with an average age of 62.5 ± 7.0 years were included. For the macroscopic assessment, 3 parameters, villous hypertrophy, hyperemia, and density, were measured and translated into grades in 3 regions-of-interest (ROI) in the glenohumeral joint and 4 ROIs in the subacromial space. For the microscopic assessments, 4 commonly used microscopic assessment systems were used. The reliability and association between the macroscopic and microscopic assessments were investigated.

Results

The inter- and intra-observer reliability of all of the macroscopic and microscopic assessments were excellent. The severity of synovitis was significantly greater in the glenohumeral joint than that in the subacromial space, 1.54 ± 0.61 versus 0.94 ± 0.56 (p < 0.001). Synovitis varied with respect to location, and was generally more severe near the tear with the macroscopic assessment system. Meanwhile, none of the microscopic assessment systems demonstrated differences between different ROIs in both the glenohumeral joint and the subacromial space.

Conclusions

The macroscopic assessment system for synovitis in rotator cuff disease in this study showed excellent reliability. It critically described characteristics of synovitis that microscopic assessment systems could not. Therefore, this system could be a useful tool for investigating synovitis in rotator cuff disease.

Smoking Predisposes to Rotator Cuff Pathology and Shoulder Dysfunction: A Systematic Review

PURPOSE

To investigate the association of smoking with rotator cuff (RTC) disease and shoulder dysfunction, defined as poor scores on shoulder rating scales.

METHODS

A systematic review was performed using a search strategy based on "shoulder AND [smoke OR smoking OR nicotine OR tobacco]." English-language clinical or basic science studies testing the association of smoking and shoulder dysfunction on shoulder rating scales or disease of the soft tissue of the shoulder were included. Level V evidence studies and articles reporting only on surgery outcomes, subjective symptoms, adhesive capsulitis, or presence of fracture or oncologic mass were excluded.

RESULTS

Thirteen studies were included, comprising a total of 16,172 patients, of whom 6,081 were smokers. All 4 clinical studies addressing the association between smoking and patient-reported shoulder symptoms and dysfunction in terms of poor scores on shoulder rating scales (i.e., Simple Shoulder Test; University of California, Los Angeles shoulder scale; and self-reported surveys) confirmed this correlation with 6,678 patients, of whom 1,723 were smokers. Two of four studies documenting provider-reported RTC disease comprised 8,461 patients, of whom 4,082 were smokers, and found a time- and dose-dependent relation of smoking with RTC tears and a correlation of smoking with impingement syndrome. Smoking was also reported in 4 other articles to be associated with the prevalence of larger RTC tears or tears with pronounced degenerative changes in 1,033 patients, of whom 276 were smokers, and may accelerate RTC degeneration, which could result in tears at a younger age. In addition, 1 basic science study showed that nicotine increased stiffness of the supraspinatus tendon in a rat model.

CONCLUSIONS

Smoking is associated with RTC tears, shoulder dysfunction, and shoulder symptoms. Smoking may also accelerate RTC degeneration and increase the prevalence of larger RTC tears. These correlations suggest that smoking may increase the risk of symptomatic RTC disease, which could consequently increase the need for surgical interventions.

LEVEL OF EVIDENCE

Level IV, systematic review of Level II through IV studies.

Targeted knockout of TNF-α by injection of lentivirus-mediated siRNA into the subacromial bursa for the treatment of subacromial bursitis in rats

Subacromial bursitis (SAB) is the major source of pain in rotator cuff disease. Although multiple investigations have provided support for the role of inflammatory cytokines in SAB, few have focussed on the use these cytokines in the treatment of SAB. The aim of the present study was to observe the therapeutic efficacy of lentivirus‑mediated RNA interference (RNAi) on carrageenan‑induced SAB by injecting lentivirus‑tumor necrosis factor (TNF)‑α‑RNAi expressing TNF‑α small interfering (si)RNA. Using screened siRNA segments, an siRNA was designed. A lentivirus vector expressing siRNA was established and packed as lentivirus particles. A lentivirus that expressed the negative sequence was used as a lentivirus‑negative control (NC). The carrageenan‑induced SAB model was established in 32 male Sprague‑Dawley rats. The modeled rats were randomly assigned to four groups: Lentivirus‑RNAi treatment group, lentivirus‑NC group, SAB group and phosphate‑buffered saline (PBS) blank control group. The lentivirus was injected (1x10(7) transducing units) into the subacromial bursa of the rats in the lentivirus‑RNAi group and lentivirus‑NC group, whereas 100 µl PBS was injected at the same site in the SAB group and the PBS blank control group. At 5 weeks following injection, the animals were sacrificed and venous blood was obtained. The effect of TNF‑α interference and the expression of inflammatory cytokines were determined by reverse transcription‑quantitative polymerase chain reaction, western blotting, hematoxylin and eosin staining, Van Gieson's staining and immunofluorescence. The expression of TNF‑α was decreased in the lentivirus‑TNF‑α‑RNAi group compared with that in the SAB group. Morphological observations revealed that the number of inflammatory cells were reduced and damage to tendon fibers was attenuated in this group, suggesting that the downregulation of the protein expression levels of TNF‑α‑associated nuclear factor‑κB, matrix metalloproteinase (MMP)1, MMP9, cyclooxygenase (COX)‑1 and COX‑2 may exert a therapeutic effect on inflammation of the SAB caused by rheumatoid arthritis. It was also found that the expression of stromal cell‑derived growth factor‑1 was downregulated in the lentivirus‑TNF‑α‑RNAi group. Therefore, the present study demonstrated that lentivirus‑mediated TNF‑α RNAi effectively inhibited the inflammatory response in SAB, and that injection of a lentivirus vector into the affected region is an effective way of achieving RNAi in vivo.

Shoulder pain and intra-articular interleukin-8 levels in patients with rotator cuff tears

AIM

Rotator cuff disease (RCD) is one of the most common disorders in the shoulder joint and causes joint pain and functional disability. In this study, we investigated the associations among cytokine levels and clinical symptoms in patients with RCD.

METHOD

Joint fluid specimens of the shoulder joint were obtained from 38 patients with RCD before arthroscopic surgery. The levels of inflammatory cytokines, including interleukin (IL)-1β, IL-6 and IL-8, were evaluated using enzyme-linked immunosorbent assay kits, and the associations between these cytokine levels and the clinical symptoms were determined. A multiple linear regression analysis was performed to identify the parameters accounting for the visual analogue scale (VAS) score at rest.

RESULTS

IL-8 level was correlated with IL-6 (r = 0.434, P = 0.006) and IL-1β (r = 0.575, P < 0.001) levels. The cuff tear size was inversely correlated with the VAS score at rest. A multiple stepwise linear regression analysis revealed that the VAS score at rest could be explained by the VAS score at night, the VAS score during movement and the intra-articular IL-8 level (adjusted R² = 0.544, P < 0.001). The intra-articular IL-8 level is associated with resting pain in rotator cuff tear patients.

CONCLUSION

These results suggest that an increased concentration of IL-8 is associated with resting pain in rotator cuff tear patients.

Proteomics perspectives in rotator cuff research: a systematic review of gene expression and protein composition in human tendinopathy

BACKGROUND

Rotator cuff tendinopathy including tears is a cause of significant morbidity. The molecular pathogenesis of the disorder is largely unknown. This review aimed to present an overview of the literature on gene expression and protein composition in human rotator cuff tendinopathy and other tendinopathies, and to evaluate perspectives of proteomics--the comprehensive study of protein composition--in tendon research.

MATERIALS AND METHODS

We conducted a systematic search of the literature published between 1 January 1990 and 18 December 2012 in PubMed, Embase, and Web of Science. We included studies on objectively quantified differential gene expression and/or protein composition in human rotator cuff tendinopathy and other tendinopathies as compared to control tissue.

RESULTS

We identified 2199 studies, of which 54 were included; 25 studies focussed on rotator cuff or biceps tendinopathy. Most of the included studies quantified prespecified mRNA molecules and proteins using polymerase chain reactions and immunoassays, respectively. There was a tendency towards an increase of collagen I (11 of 15 studies) and III (13 of 14), metalloproteinase (MMP)-1 (6 of 12), -9 (7 of 7), -13 (4 of 7), tissue inhibitor of metalloproteinase (TIMP)-1 (4 of 7), and vascular endothelial growth factor (4 of 7), and a decrease in MMP-3 (10 of 12). Fourteen proteomics studies of tendon tissues/cells failed inclusion, mostly because they were conducted in animals or in vitro.

CONCLUSIONS

Based on methods, which only allowed simultaneous quantification of a limited number of prespecified mRNA molecules or proteins, several proteins appeared to be differentially expressed/represented in rotator cuff tendinopathy and other tendinopathies. No proteomics studies fulfilled our inclusion criteria, although proteomics technologies may be a way to identify protein profiles (including non-prespecified proteins) that characterise specific tendon disorders or stages of tendinopathy. Thus, our results suggested an untapped potential for proteomics in tendon research.

Arthroscopic versus mini-open rotator cuff repair: an up-to-date meta-analysis of randomized controlled trials

PURPOSE

The aim of this meta-analysis was to compare the clinical outcomes of arthroscopic and mini-open rotator cuff repairs based on recently published Level I randomized controlled trials (RCTs).

METHODS

We systematically searched electronic databases to identify RCTs that compared arthroscopic and mini-open rotator cuff repairs from 1980 to October 2013. The clinical outcome scores, including the University of California, Los Angeles score and the Constant-Murley score, were converted to a common 100-point outcome score for further analysis. The results of the pooled studies were analyzed in terms of surgery time, weighted 100-point score, pain on a visual analog scale (VAS), and range of motion. Study quality was assessed and relevant data were extracted independently by 2 reviewers.

RESULTS

Five RCTs, including 166 patients in the arthroscopic repair group and 163 patients in the mini-open repair group, were included in this meta-analysis. The results of the meta-analysis showed that there were no significant differences in surgery time (P = .11), weighted 100-point score (P = .65), VAS pain score (P = .87), or range of motion (P = .29 for forward flexion and P = .82 for external rotation).

CONCLUSIONS

On the basis of current literature, no differences in surgery time, functional outcome score, VAS pain score, and range of motion were found at the end of follow-up between the arthroscopic and mini-open rotator cuff repair techniques. In addition, there was no significant difference in VAS pain score in the early phase between the 2 repairs.

LEVEL OF EVIDENCE

Level I, meta-analysis of Level I studies.

Induction of nerve growth factor expression and release by mechanical and inflammatory stimuli in chondrocytes: possible involvement in osteoarthritis pain

Introduction

Nerve growth factor (NGF) level is increased in osteoarthritis (OA) joints and is involved in pain associated with OA. Stimuli responsible for NGF stimulation in chondrocytes are unknown. We investigated whether mechanical stress and proinflammatory cytokines may influence NGF synthesis by chondrocytes.

Methods

Primary cultures of human OA chondrocytes, newborn mouse articular chondrocytes or cartilage explants were stimulated by increasing amounts of IL-1β, prostaglandin E₂ (PGE₂), visfatin/nicotinamide phosphoribosyltransferase (NAMPT) or by cyclic mechanical compression (0.5 Hz, 1 MPa). Before stimulation, chondrocytes were pretreated with indomethacin, Apo866, a specific inhibitor of NAMPT enzymatic activity, or transfected by siRNA targeting visfatin/NAMPT. mRNA NGF levels were assessed by real-time quantitative PCR and NGF released into media was determined by ELISA.

Results

Unstimulated human and mouse articular chondrocytes expressed low levels of NGF (19.2 ± 8.7 pg/mL, 13.5 ± 1.0 pg/mL and 4.4 ± 0.8 pg/mL/mg tissue for human and mouse articular chondrocytes and costal explants, respectively). Mechanical stress induced NGF release in conditioned media. When stimulated by IL-1β or visfatin/NAMPT, a proinflammatory adipokine produced by chondocytes in response to IL-1β, a dose-dependent increase in NGF mRNA expression and NGF release in both human and mouse chondrocyte conditioned media was observed. Visfatin/NAMPT is also an intracellular enzyme acting as the rate-limiting enzyme of the generation of NAD. The expression of NGF induced by visfatin/NAMPT was inhibited by Apo866, whereas IL-1β-mediated NGF expression was not modified by siRNA targeting visfatin/NAMPT. Interestingly, PGE₂, which is produced by chondrocytes in response to IL-1β and visfatin/NAMPT, did not stimulate NGF production. Consistently, indomethacin, a cyclooxygenase inhibitor, did not counteract IL-1β-induced NGF production.

Conclusions

These results show that mechanical stress, IL-1β and extracellular visfatin/NAMPT, all stimulated the expression and release of NGF by chondrocytes and thus suggest that the overexpression of visfatin/NAMPT and IL-1β in the OA joint and the increased mechanical loading of cartilage may mediate OA pain via the stimulation of NGF expression and release by chondrocytes.

Role of serum fibrinogen levels in patients with rotator cuff tears

Although rotator cuff (RC) tendinopathy is a frequent pathology of the shoulder, the real understanding of its aetiopathogenesis is still unclear. Several studies showed that RC tendinopathy is more frequent in patients with hyperglycemia, diabetes, obesity, or metabolic syndrome. This paper aims to evaluate the serum concentration of fibrinogen in patients with RC tears. Metabolic disorders have been related to high concentration of serum fibrinogen and the activity of fibrinogen has been proven to be crucial in the development of microvascular damage. Thus, it may produce progression of RC degeneration by reducing the vascular supply of tendons. We report the results of a cross-sectional frequency-matched case-control study comparing the serum concentration of fibrinogen of patients with RC tears with that of a control group of patients without history of RC tears who underwent arthroscopic meniscectomy. We choose to enrol in the control group patients with pathology of the lower limb with a likely mechanic, not metabolic, cause, different from tendon pathology. We found no statistically significant differences in serum concentration of fibrinogen when comparing patients with RC tears and patients who underwent arthroscopic meniscectomy (P = 0.5). Further studies are necessary to clarify the role of fibrinogen in RC disease.

Inflammatory cytokines are overexpressed in the subacromial bursa of frozen shoulder

BACKGROUND

Frozen shoulder is a debilitating condition characterized by gradual loss of glenohumeral motion with chronic inflammation and capsular fibrosis. Yet its pathogenesis remains largely unknown. We hypothesized that the subacromial bursa may be responsible for the pathogenesis of frozen shoulder by producing inflammatory cytokines.

MATERIALS AND METHODS

We obtained joint capsules and subacromial bursae from 14 patients with idiopathic frozen shoulder and from 7 control subjects to determine the expression levels of interleukin (IL) 1α, IL-1β, IL-6, tumor necrosis factor α (TNF-α), cyclooxygenase (COX) 1, and COX-2 by real-time reverse transcriptase-polymerase chain reaction, immunohistochemistry, and enzyme-linked immunosorbent assay.

RESULTS

IL-1α, IL-1β, TNF-α, COX-1, and COX-2 were expressed at significantly high levels in the joint capsules of the frozen shoulder group compared with those of the control group. Intriguingly, IL-1α, TNF-α, and COX-2 were also expressed at significantly high levels in the subacromial bursae of the frozen shoulder group compared with those of the control group. Immunohistochemical analysis showed increased expression of COX-2 in both the joint capsules and subacromial bursae of the frozen shoulder group.

CONCLUSIONS

These findings imply that elevated levels of inflammatory cytokines in the subacromial bursa may be associated with the pathogenesis of inflammation evolving into fibrosis.

Shoulder morbidity after treatment for breast cancer is bilateral and greater after mastectomy

BACKGROUND

A recent study in our laboratory found significant differences in scapular kinematics between the affected and unaffected sides of women reporting shoulder pain following treatment for breast cancer. An earlier smaller study from our laboratory found reduced muscle activity from four key muscles and an association with greater shoulder pain and disability. The aims of this study were to: correlate altered muscle activity from a larger sample with observed movement deviations; compare within subject movement and muscle deviations in survivors with healthy variation; explore the impact of a mastectomy vs. a wide local excision (WLE) on the observed deviations.

METHOD

Cross-sectional study. One hundred and fifty-five women treated for unilateral carcinoma of the breast and 21 age-matched healthy women were included in the study. All patients filled out the Shoulder Pain and Disability Index (SPADI). Three-dimensional (3D)-kinematic data and EMG muscle activity were recorded during scaption on the affected and unaffected side. The association between kinematic data, EMG data, SPADI and covariates was determined using a two stage, random effects mixed multiple regression technique.

RESULTS

All scapula kinematic and muscle EMG parameters in both arms were altered in breast cancer survivors when compared to healthy participants. Altered movement patterns were different for left vs. right side affected. Mastectomy patients demonstrated greater movement deviations and reported significantly higher levels of pain than WLE patients.

CONCLUSION

Shoulder morbidity is bilateral, greater in patients having a mastectomy and is present for up to six years post-surgery. This study and others now provide ample evidence to support prospective surveillance programmes that can be integrated into Survivorship Programmes.

A systematic review of the histological and molecular changes in rotator cuff disease

INTRODUCTION

The pathogenesis of rotator cuff disease (RCD) is complex and not fully understood. This systematic review set out to summarise the histological and molecular changes that occur throughout the spectrum of RCD.

METHODS

We conducted a systematic review of the scientific literature with specific inclusion and exclusion criteria.

RESULTS

A total of 101 studies met the inclusion criteria: 92 studies used human subjects exclusively, seven used animal overuse models, and the remaining two studies involved both humans and an animal overuse model. A total of 58 studies analysed supraspinatus tendon exclusively, 16 analysed subacromial bursal tissue exclusively, while the other studies analysed other tissue or varying combinations of tissue types including joint fluid and muscle. The molecular biomarkers that were altered in RCD included matrix substances, growth factors, enzymes and other proteins including certain neuropeptides.

CONCLUSIONS

The pathogenesis of RCD is being slowly unravelled as a result of the significant recent advances in molecular medicine. Future research aimed at further unlocking these key molecular processes will be pivotal in developing new surgical interventions both in terms of the diagnosis and treatment of RCD.

Collagen production at the edge of ruptured rotator cuff tendon is correlated with postoperative cuff integrity

PURPOSE

The purpose was to evaluate the correlation between messenger RNA (mRNA) expression of collagen at the edge of the ruptured rotator cuff tendon and postoperative cuff integrity.

METHODS

The edge of the ruptured tendon was sampled during open rotator cuff surgery in 12 patients with full-thickness rotator cuff tears (mean age, 58.2 years). The mean period from symptom onset was 9.3 months (range, 1 to 36 months), and the mean tear size was 4.1 cm. As controls, rotator cuff tendons with no gross rupture were taken from 5 fresh cadavers. Production of type I and type III collagen was examined by real-time reverse transcription polymerase chain reaction. By use of magnetic resonance imaging, postoperative cuff integrity was evaluated based on the classification of Sugaya et al. and then scored, ranging from 5 points for type I to 1 point for type V.

RESULTS

Looking at the mRNA of type I and type III collagen in tendons, we found that the expression of mRNA for both collagen types in ruptured tendons was significantly greater than in control tendons (P = .0462 for type I collagen and P = .0306 for type III collagen). Correlating the mRNA of type I and type III collagen with repaired cuff integrity on postoperative magnetic resonance imaging, we found a close relation between expression of mRNA for both collagen types and postoperative rotator cuff integrity (r = 0.63 [P = .038] for type I collagen and r = 0.626 [P = .03] for type III collagen). Furthermore, expression of type I collagen mRNA showed a significant inverse correlation with the period from symptom onset (r = -0.845, P < .0005).

CONCLUSIONS

This study showed that expression of mRNA for type I and type III collagen at the edge of the ruptured rotator cuff tendon was significantly correlated with postoperative cuff integrity and that mRNA expression for type I collagen was significantly associated with the period from symptom onset. These results may suggest that conservative treatment should not be prolonged if patients do not respond within a certain period.

LEVEL OF EVIDENCE

Level III, prognostic case-control study.

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.

Prospective randomised comparison of arthroscopic versus mini-open rotator cuff repair of the supraspinatus tendon

PURPOSE

The aim of the study was to evaluate whether arthroscopic (ASC) repair of rotator cuff ruptures causes less postoperative pain and better range of motion (ROM) in the early postoperative period than a mini-open (MO) technique.

METHODS

Inclusion criteria were a rupture of the supraspinatus tendon with retraction with a maximum to the apex of the humeral head and minor fatty degeneration and atrophy of the muscle. Each group (n = 17) had similar demographics and preoperative magnetic resonance imaging (MRI) findings (mean age 60.1 years, SD 8.8, range 43-71). The ASC group underwent double-row repair with resorbable anchors; the MO group received a transosseous repair. The postoperative rehabilitation was standardised and equivalent in both groups.

RESULTS

In the first week fewer nonsteroidal anti-inflammatory drug (NSAID) tablets were needed in the ASC group. Pain scores on the visual analogue scale were similar in the first three weeks; however, from week four to eight the MO group had less pain (p < 0.05). After six months, the Constant-Murley score and the ROM improved significantly (p < 0.05) in both groups without differences between the groups. Postoperative MRI revealed in three of 16 patients a discontinuity of the tendon in both groups; in the ASC group there were more patients (n = 9) with a thinning of the tendon compared to the MO group (n = 6).

CONCLUSIONS

There was less use of NSAIDs in the first postoperative week in the ASC group, indirectly indicating less pain, but higher pain scores in the later course (weeks four to eight) compared to the MO group. ROM, MRI findings and the scores were similar after six months, demonstrating that both techniques are equivalent regarding the outcome in this period.

Lifestyle and metabolic factors in relation to shoulder pain and rotator cuff tendinitis: a population-based study

Background

Shoulder pain is a common health problem. The purpose of this study was to assess the associations of lifestyle factors, metabolic factors and carotid intima-media thickness with shoulder pain and chronic (> 3 months) rotator cuff tendinitis.

Methods

In this cross-sectional study, the target population consisted of subjects aged 30 years or older participating in a national Finnish Health Survey during 2000-2001. Of the 7,977 eligible subjects, 6,237 (78.2%) participated in a structured interview and clinical examination. Chronic rotator cuff tendinitis was diagnosed clinically. Weight-related factors, C-reactive protein and carotid intima-media thickness were measured.

Results

The prevalence of shoulder joint pain during the preceding 30 days was 16% and that of chronic rotator cuff tendinitis 2.8%. Smoking, waist circumference and waist-to-hip ratio were related to an increased prevalence of shoulder pain in both genders. Metabolic syndrome, type 2 diabetes mellitus and carotid intima-media thickness were associated with shoulder pain in men, whereas high level of C-reactive protein was associated with shoulder pain in women. Increased waist circumference and type 1 diabetes mellitus were associated with chronic rotator cuff tendinitis in men.

Conclusions

Our findings showed associations of abdominal obesity, some other metabolic factors and carotid intima-media thickness with shoulder pain. Disturbed glucose metabolism and atherosclerosis may be underlying mechanisms, although not fully supported by the findings of this study. Prospective studies are needed to further investigate the role of lifestyle and metabolic factors in shoulder disorders.

Long lasting pain hypersensitivity following ligation of the tendon of the masseter muscle in rats: a model of myogenic orofacial pain

Background

A major subgroup of patients with temporomandibular joint (TMJ) disorders have masticatory muscle hypersensitivity. To study myofacial temporomandibular pain, a number of preclinical models have been developed to induce myogenic pain of the masseter muscle, one of the four muscles involved in mastication. The currently used models, however, generate pain that decreases over time and only lasts from hours to weeks and hence are not suitable for studying chronicity of the myogenic pain in TMJ disorders. Here we report a model of constant myogenic orofacial pain that lasts for months.

Results

The model involves unilateral ligation of the tendon of the anterior superficial part of the rat masseter muscle (TASM). The ligation of the TASM was achieved with two chromic gut (4.0) ligatures via an intraoral approach. Nocifensive behavior of the rat was assessed by probing the skin site above the TASM with a series of von Frey filaments. The response frequencies were determined and an EF₅₀ value, defined as the von Frey filament force that produces a 50% response frequency, was derived and used as a measure of mechanical sensitivity. Following TASM ligation, the EF₅₀ of the injured side was significantly reduced and maintained throughout the 8-week observation period, suggesting the presence of mechanical hyperalgesia/allodynia. In sham-operated rats, the EF₅₀ of the injured side was transiently reduced for about a week, likely due to injury produced by the surgery. Somatotopically relevant Fos protein expression was indentified in the subnucleus caudalis of the spinal trigeminal sensory complex. In the same region, persistent upregulation of NMDA receptor NR1 phosphorylation and protein expression and increased expression of glial markers glial fibrillary acidic protein (astroglia) and CD11b (microglia) were found. Morphine (0.4-8 mg/kg, s.c.) and duloxetine (0.4-20 mg/kg, i.p.), a selective serotonin-norepinephrine reuptake inhibitor, produced dose-dependent attenuation of hyperalgesia.

Conclusions

Ligation injury of the TASM in rats led to long-lasting and constant mechanical hypersensitivity of myogenic origin. The model will be particularly useful in studying the chronicity of myogenic pain TMJ disorders. The model can also be adapted to other regions of the body for studying pathology of painful tendinopathy seen in sports injury, muscle overuse, and rheumatoid arthritis.

The prevalence of neovascularity in patients clinically diagnosed with rotator cuff tendinopathy

Background

Shoulder dysfunction is common and pathology of the rotator cuff tendons and subacromial bursa are considered to be a major cause of pain and morbidity. Although many hypotheses exist there is no definitive understanding as to the origin of the pain arising from these structures. Research investigations from other tendons have placed intra-tendinous neovascularity as a potential mechanism of pain production. The prevalence of neovascularity in patients with a clinical diagnosis of rotator cuff tendinopathy is unknown. As such the primary aim of this pilot study was to investigate if neovascularity could be identified and to determine the prevalence of neovascularity in the rotator cuff tendons and subacromial bursa in subjects with unilateral shoulder pain clinically assessed to be rotator cuff tendinopathy. The secondary aims were to investigate the association between the presence of neovascularity and pain, duration of symptoms, and, neovascularity and shoulder function.

Methods

Patients with a clinical diagnosis of unilateral rotator cuff tendinopathy referred for a routine diagnostic ultrasound (US) scan in a major London teaching hospital formed the study population. At referral patients were provided with an information document. On the day of the scan (on average, at least one week later) the patients agreeing to participate were taken through the consent process and underwent an additional clinical examination prior to undergoing a bilateral grey scale and colour Doppler US examination (symptomatic and asymptomatic shoulder) using a Philips HDI 5000 Sono CT US machine. The ultrasound scans were performed by one of two radiologists who recorded their findings and the final assessment was made by a third radiologist blinded both to the clinical examination and the ultrasound examination. The findings of the radiologists who performed the scans and the blinded radiologist were compared and any disagreements were resolved by consensus.

Results

Twenty-six patients agreed to participate and formed the study population. Of these, 6 subjects were not included in the final assessment following the pre-scan clinical investigation. This is because one subject had complete cessation of symptoms between the time of the referral and entry into the trial. Another five had developed bilateral shoulder pain during the same period. The mean age of the 20 subjects forming the study population was 50.2 (range 32-69) years (SD = 10.9) and the mean duration of symptoms was 22.6 (range .75 to 132) months (SD = 40.1). Of the 20 subjects included in the formal analysis, 13 subjects (65%) demonstrated neovascularity in the symptomatic shoulder and 5 subjects (25%) demonstrated neovascularity in the asymptomatic shoulder. The subject withdrawn due to complete cessation of symptoms was not found to have neovascularity in either shoulder and of the 5 withdrawn due to bilateral symptoms; two subjects were found to have signs of bilateral neovascularity, one subject demonstrated neovascularity in one shoulder and two subjects in neither shoulder.

Conclusions

This study demonstrated that neovascularity does occur in subjects with a clinical diagnosis of rotator cuff tendinopathy and to a lesser extent in asymptomatic shoulders. In addition, the findings of this investigation did not identify an association between the presence of neovascularity; and pain, duration of symptoms or shoulder function. Future research is required to determine the relevance of these findings.