RETRACTED ARTICLE: Inflammation and shoulder pain—a perspective on rotator cuff disease, adhesive capsulitis, and osteoarthritis: conservative treatment

Cytokines' Role in the Pathogenesis and Their Targeting for the Prevention of Frozen Shoulder: A Narrative Review

Frozen shoulder (FS) is a common name for shoulder movement limitation with different degrees of shoulder rigidity and pain. It is characterized by varying developmental courses, different levels of shoulder movement limitation, and background ambiguity due to the multiplicity of its causative factors. Systemic inflammatory cytokines monitoring and restraining is easy to apply, fast to conduct, and needs lower costs compared to invasive methods for frozen shoulder stage evaluation and early controlling of its progress to the stage that necessitates surgical intervention. The aim of this review was to assess the recent findings concerning the role of cytokines in FS pathogenesis and the possibility of preventing or controlling their progress through targeting these cytokines by the new drugs candidates, such as hyaluronan (HA), botulinum toxin type A (BoNT A), Tetrandrine, tumor necrosis factor-stimulated gene-6 (TSG-6), and cannabidiol. Searching the PubMed site, we encountered out of 1608 records, from which 16 original studies were included for the quantitative construction of this systematic review screening of the recent studies to investigate the different FS pathogenic pathways. Most of the scenarios are centered around the inflammatory and fibrotic process triggered by synovial and capsular fibroblast stimulation. This mechanism depends mainly on alarmins cytokines, including thymic stromal lymphopoietin (TSLP), interleukin-33 (IL-33), and interleukin-25 (IL-25), with the stimulation of interleukin-1 α (IL-1α), interleukin-1 β (IL-1β), tumor necrosis alpha (TNF-α), cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) in a joint capsule. Different pathways of transforming growth factor- β (TGF-β) stimulation, resulting in overexpression of the fibrotic factors as tenascin C (TNC), fibronectin 1, collagen I (COL 1) and collagen III (COL III), and matrix metalloproteinases (MMPs) in the capsular or synovial/capsular fibroblasts. The overall investigation of these studies led us to conclude that the new drug candidates proved their efficiency in controlling the common pathogenesis of the inflammatory and fibrotic pathways of frozen shoulder and therefore represent a prospect for easy and early controlling and efficiently treating this serious disease.

Allogenic Pure Platelet-Rich Plasma Therapy for Adhesive Capsulitis: A Bed-to-Bench Study With Propensity Score Matching Using a Corticosteroid Control Group

BACKGROUND

While platelet-rich plasma (PRP) has been widely studied for musculoskeletal disorders, few studies to date have reported its use for adhesive capsulitis (AC). Fully characterized and standardized allogenic PRP may provide clues to solve the underlying mechanism of PRP with respect to synovial inflammation and thus may clarify its clinical indications.

PURPOSE

To clinically evaluate the safety and efficacy of a fully characterized pure PRP injection in patients with AC and to assess the effects of pure PRP on synoviocytes with or without inflammation in vitro.

STUDY DESIGN

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

METHODS

For the clinical analysis, a total of 15 patients with AC received an ultrasonography-guided intra-articular PRP injection and were observed for 6 months. Pain, range of motion (ROM), muscle strength, shoulder function, and overall satisfaction in the patients were evaluated using questionnaires at 1 week as well as at 1, 3, and 6 months after the PRP injection and results were compared with the results of a propensity score-matched control group that received a corticosteroid injection (40 mg triamcinolone acetonide). For the in vitro analysis, synoviocytes were cultured with or without interleukin-1β (IL-1β) and PRP. The gene expression of proinflammatory and anti-inflammatory cytokines as well as matrix enzymes and their inhibitors was evaluated.

RESULTS

At 6-month follow-up, pure PRP significantly decreased pain and improved ROM, muscle strength, and shoulder function to levels comparable with those after a corticosteroid injection. All pain values, strength measurements, and functional scores significantly improved up to 6 months in the PRP group, but these measures improved up to 3 months and then were decreased at 6 months in the corticosteroid group. ROM was significantly improved in the 2 groups at 6 months compared with baseline. Allogenic PRP did not cause adverse events. For the in vitro findings, PRP induced inflammation but significantly improved the IL 1β-induced synovial inflammatory condition by decreasing proinflammatory cytokines such as IL-1β, tumor necrosis factor-α, IL-6, cyclooxygenase-2, and microsomal prostaglandin E synthase-1 and decreased matrix enzymes (matrix metalloproteinase-1, -3, and -13 as well as a disintegrin and metalloproteinase with thrombospondin motifs-4 and -5) and further increasing anti-inflammatory cytokines such as vasoactive intestinal peptide.

CONCLUSION

This study showed that PRP decreased pain and improved shoulder ROM and function to an extent comparable with that of a corticosteroid in patients with AC. Allogenic pure PRP acted in a pleiotropic manner and decreased proinflammatory cytokines only in the inflammatory condition.

CLINICAL RELEVANCE

Allogenic PRP could be a treatment option for the inflammatory stage of AC.

Pathological changes of frozen shoulder in rat model and the therapeutic effect of PPAR-γ agonist

Frozen shoulder is a common shoulder disorder characterized by a gradual increase of pain and a limited range of motion. However, its pathophysiologic mechanisms remain unclear and there is no consensus as to the most effective treatment. The purpose of the study was to investigate the effect of transforming growth factor-β (TGF-β) on fibrosis and inflammatory response of the shoulder joint of rat models and to explore the therapeutic effect of the peroxisome proliferator-activated receptor-γ (PPAR-γ) agonist. In the study, the effect of PPAR-γ agonist CDDO-IM treatment on cell proliferation, migration, and extracellular matrix proteins synthesis (vimentin, α-smooth muscle actin, collagen I, and collagen III) were tested by cell proliferation test, scratches test, real-time quantitative polymerase chain reaction, and Western blot analysis. The frozen shoulder was also established on the rat model by injecting adenovirus-TGF-β1 into rats' shoulder capsule. Pathological changes of the frozen shoulder tissue of the experimental group and PPAR-γ agonist treatment group were evaluated. The stiffness of joints of the three groups was tested. Inflammatory mediators' expression including cyclooxygenase-1, interleukin-1β, and tumor necrosis factor-α of the shoulder was tested by enzyme-linked immunosorbent assay, and the expression of extracellular matrix proteins was evaluated by hematoxylin and eosin staining and immunohistochemistry. The results showed that pathological changes of the frozen shoulder in the rat model include an abnormal proliferation of fibroblasts, infiltration of inflammatory cells, and disorder of fibrous structure, while rosiglitazone reduced the severity of the frozen shoulder in the treatment group. Clinically, PPAR-γ agonists may be a promising target for the treatment of the frozen shoulder.

KDR inferred haplotype is associated with upper limb dysfunction in breast cancer survivors of mixed ancestry

Introduction: Shoulder pain and disability are well-documented sequelae of breast cancer treatment. Angiogenesis signaling may have a role in the development of shoulder pain or shoulder disability in breast cancer survivors. The aim of this study was to determine if polymorphisms in angiogenesis-related genes are associated with shoulder pain or disability following breast cancer treatment.

Participants and methods: A cross-sectional study was conducted on 220 South African breast cancer survivors. The study aimed to evaluate associations between shoulder pain/disability and seven single nucleotide polymorphisms (SNPs) within five angiogenesis-associated genes: KDR (rs2305948 C>T; rs7667298 C>T), NOS3 (rs1549758 C>T), MMP2 (rs708269 A>T), THBS2 (rs9766678 A>G) and TIMP3 (rs5754312 T>A; rs715572 G>A). In addition, associations between shoulder pain/disability and inferred haplotypes for KDR and TIMP3 SNPs were evaluated. Participants were grouped into no–low and moderate–high shoulder pain/disability based on total pain/disability scores: ≤30 and >30, respectively using the shoulder pain and disability index (SPADI).

Results: No independent associations with shoulder pain/disability categories were found for all SNPs. However, 1 inferred haplotype (KDR “TT”) differed significantly (P=0.014) between the shoulder disability categories. After adjusting for participants’ age, the differences in KDR inferred haplotype frequencies between shoulder disability categories became non-significant (P=0.052).

Conclusion: Our findings provide a preliminary suggestion of a possible association between polymorphisms in genes involved in angiogenesis and the presence of moderate–high shoulder disability among South African breast cancer survivors. A larger prospective cohort study is currently being conducted by our group.

Biological Aspect of Pathophysiology for Frozen Shoulder

It is fairly well understood that frozen shoulder involves several stages, which reflect the series of process from capsular inflammation and fibrosis to spontaneous resolution of this fibrosis. However, the underlying pathophysiologic process remains poorly determined. For this reason, management of frozen shoulder remains controversial. Determining the pathophysiological processes of frozen shoulder is a pivotal milestone in the development of novel treatment for patients with frozen shoulder. This article reviews what is known to date about the biological pathophysiology of frozen shoulder. Although articles for the pathophysiology of frozen shoulder provide inconsistent and inconclusive results, they have suggested both inflammation and fibrosis mediated by cytokines, growth factors, matrix metalloproteinases, and immune cells. Proinflammatory cytokines and growth factors released from immune cells control the action of fibroblast and matrix remodeling is regulated by the matrix metalloproteinases and their inhibitors. To improve our understanding of the disease continuum, better characterizing the biology of these processes at clearly defined stages will be needed. Further basic studies that use standardized protocols are required to more narrowly identify the role of cytokines, growth factors, matrix metalloproteinases, and immune cells. The results of these studies will provide needed clarity into the control mechanism of the pathogenesis of frozen shoulder and help identify new therapeutic targets for its treatment.

A Study of IL-1β, MMP-3, TGF-β1, and GDF5 Polymorphisms and Their Association with Primary Frozen Shoulder in a Chinese Han Population

Primary frozen shoulder (PFS) is a common condition of uncertain etiology that is characterized by shoulder pain and restriction of active and passive glenohumeral motions. The pathophysiology involves chronic inflammation and fibrosis of the joint capsule. Single nucleotide polymorphisms (SNPs) at IL-1β, MMP3, TGF-β1, and GDF5 have been associated with risk of a variety of inflammatory diseases; however, no studies have examined these SNPs with susceptibility to PFS. We investigated allele and genotype frequencies of rs1143627 at IL-1β, rs650108 at MMP-3, rs1800469 at TGF-β1, and rs143383 at GDF5 in 42 patients with PFS and 50 healthy controls in a Chinese Han population. Serum samples from both cohorts were evaluated to determine the expression levels of IL-1β. We found that the IL-1β rs1143627 CC genotype was associated with a decreased risk of PFS compared to the TT genotype (P = 0.022) and that serum IL-1β was expressed at a significantly higher level in the PFS cohort compared to that found in the control group (P < 0.001). Our findings indicated no evidence of an association between rs650108, rs1800469, or rs143383 and PFS. IL-1β is associated with susceptibility to PFS and may have a role in its pathogenesis in a Chinese Han population.

Up-regulation of acid-sensing ion channels in the capsule of the joint in frozen shoulder

The purpose of this study was to evaluate the expression of acid-sensing ion channels (ASICs) in the capsule and synovial fluid of patients with frozen shoulder. Capsular tissue and synovial fluid were obtained from 18 patients with idiopathic frozen shoulder (FS group) and 18 patients with instability of the shoulder (control group). The expressions of ASIC1, ASIC2, and ASIC3 in the capsule were determined using the reverse transcriptase-polymerase chain reaction, immunoblot analysis, and immunohistochemistry (IHC). The concentrations in synovial fluid were evaluated using an enzyme-linked immunosorbent assay.

The mRNA expression of ASIC1, ASIC2 and ASIC3 in the capsule were significantly increased in the FS group compared with the control group. The protein levels of these three ASICs were also increased. The increased expressions were confirmed by IHC. Of the ASICs, ASIC3 showed the greatest increase in both mRNA and levels of expression compared with the control group. The levels of ASIC1 and ASIC3 in synovial fluid were significantly increased in the FS group.

This study suggests that ASICs may play a role as mediators of inflammatory pain and be involved in the pathogenesis of frozen shoulder.

Cite this article: Bone Joint J 2015;97-B:824–9.

Evaluation of rotator cuff muscle strength in healthy individuals

OBJECTIVE:

To compare the strength generated by the rotator muscles of the shoulder joint between the right upper limb and left upper limb among healthy individuals.

METHODS:

To evaluate the muscle strength of upper limbs from isometric contractions in the horizontal direction (rotation) an isometric dynamometer was used, equipped with transducers, signal conditioning, a data acquisition board, and finally, a computer. Study participants were 22 male military subjects, aged between 18 and 19 years old, body mass between 57.7 and 93.0 kg (71.8 ± 9.45 kg) and height between 1.67 and 1.90 m (1.75 ± 0.06 m), healthy and without clinical diseases or any type of orthopedic injury in the muscle skeletal system.

RESULTS:

The internal rotation in the right upper limb (RUL) was higher than the average strength of internal rotation in the left upper limb (LUL) (p = 0.723). The external rotation strength in RUL was lower than the average strength of external rotation in the LUL (p=0.788). No statistical difference was observed by comparing the strength values of all isometric strength tests.

CONCLUSION:

For the sample and methodology used to assess muscle strength, there was no statistical difference between the strength generated by the muscles of the rotator cuff of the right and left upper limbs. Experimental Study.

Melatonin Plays a Role as a Mediator of Nocturnal Pain in Patients with Shoulder Disorders

BACKGROUND

Nocturnal pain is commonly observed in patients with shoulder disorders such as a rotator cuff tear or frozen shoulder. This study was conducted to explore the possibility that melatonin plays a role as a mediator of nocturnal pain in patients with a rotator cuff tear or frozen shoulder.

METHODS

Subacromial bursa and joint capsule samples were collected from sixty-three patients: twenty-one patients with a rotator cuff tear, twenty-two with frozen shoulder, and twenty with shoulder instability (control group). The expression of melatonin receptor 1A (MTNR1A) and 1B (MTNR1B) and of acid-sensing ion channel 3 (ASIC3) in the subacromial bursa and the joint capsule were determined by real-time reverse transcription-polymerase chain reaction (RT-PCR) analysis. The protein level of ASIC3 was measured by immunoblot analysis. To determine the effect of melatonin as a pain mediator, an in vitro study with use of primary cultured fibroblast-like synoviocytes was performed by semiquantitative RT-PCR analysis, immunoblot analysis, and enzyme-linked immunosorbent assay (ELISA).

RESULTS

MTNR1A, MTNR1B, and ASIC3 expression was significantly increased in both the rotator cuff tear and frozen shoulder groups compared with the control group of patients with shoulder instability. Interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) significantly stimulated the expression of MTNR1A and MTNR1B in primary cultured fibroblast-like synoviocytes treated with proinflammatory cytokines. Melatonin treatment at a physiological concentration (10 nM) induced ASIC3 expression and IL-6 production. Treatment with luzindole, a melatonin-receptor antagonist, reversed melatonin-stimulated ASIC3 expression and IL-6 production.

CONCLUSIONS

Our study suggests that melatonin may play a role as a mediator of nocturnal pain with a rotator cuff tear or frozen shoulder, and this effect may be mediated via melatonin receptors.

CLINICAL RELEVANCE

Melatonin may be a therapeutic target of chronotherapy.

Outcome and risk of revision following shoulder replacement in patients with glenohumeral osteoarthritis

This thesis includes four studies focusing on the functional outcome, shoulder-specific quality of life and risk of revision following shoulder replacement in patients with glenohumeral osteoarthritis without symptomatic rotator cuff pathology. The Danish version of WOOS, translated according to international standardized guidelines, had substantial psychometric properties comparable to the original version. It is recommendable to use WOOS in the evaluation of patients with glenohumeral osteoarthritis treated with shoulder replacement. Data from DSR showed that the shoulder specific quality of life following total shoulder arthroplasty was superior to that of hemiarthroplasty (resurfacing hemiarthroplasty and stemmed hemiarthroplasty). The difference between stemmed hemiarthroplasty and resurfacing hemiarthroplasty was small and did not exceed the minimal clinically important difference. The revision rate following resurfacing hemiarthroplasty was surprisingly high compared with previous reports but there were no statistical significant differences in revision rate between arthroplasty designs. The shoulder specific quality of life and revision rate in patients under the age of 55 was worrying. The use of resurfacing hemiarthroplasty has relied on the results from case series only. The efficacy in the treatment of glenohumeral osteoarthritis has been promising but the CMS found in the randomized clinical trial indicate that the functional outcome may be inferior to that of stemmed hemiarthroplasty and less favourable than previously reported. However, the limited number of patients may have influenced the results and a larger definitive RCT is needed.Shoulder replacement is relevant and effective in the treatment of glenohumeral osteoarthritis; however, resurfacing hemiarthroplasty was associated with a poorer outcome and a higher risk of revision than previously assumed especially in patients under the age of 55. Based on data from this thesis, and based on existing knowledge, it seems like total shoulder arthroplasty should be preferred in the treatment of glenohumeral osteoarthritis. Shoulder replacement is rarely indicated in younger patients where other treatment options (e.g., physiotherapy; intraarticular injections of hyaluronate; and joint preserving surgery) should be considered until the efficacy of shoulder replacement has been more thoroughly documented.

Self-correction in biomedical publications and the scientific impact

AIM

To analyze mistakes and misconduct in multidisciplinary and specialized biomedical journals.

METHODS

We conducted searches through PubMed to retrieve errata, duplicate, and retracted publications (as of January 30, 2014). To analyze publication activity and citation profiles of countries, multidisciplinary, and specialized biomedical journals, we referred to the latest data from the SCImago Journal and Country Rank database. Total number of indexed articles and values of the h-index of the fifty most productive countries and multidisciplinary journals were recorded and linked to the number of duplicate and retracted publications in PubMed.

RESULTS

Our analysis found 2597 correction items. A striking increase in the number of corrections appeared in 2013, which is mainly due to 871 (85.3%) corrections from PLOS One. The number of duplicate publications was 1086. Articles frequently published in duplicate were reviews (15.6%), original studies (12.6%), and case reports (7.6%), whereas top three retracted articles were original studies (10.1%), randomized trials (8.8%), and reviews (7%). A strong association existed between the total number of publications across countries and duplicate (rs=0.86, P<0.0001) and retracted items (rs=0.812, P<0.0001). A similar trend was found between country-based h-index values and duplicate and retracted publications.

CONCLUSION

The study suggests that the intensified self-correction in biomedicine is due to the attention of readers and authors, who spot errors in their hub of evidence-based information. Digitization and open access confound the staggering increase in correction notices and retractions.

Shoulder muscle function in frozen shoulder syndrome patients following manipulation under anesthesia: a 6-month follow-up study

INTRODUCTION

The present study evaluates changes in shoulder muscle function in patients with frozen shoulder syndrome (FSS) following manipulation under general anesthesia (MUA).

PATIENTS AND METHODS

Fifteen FSS patients with mean (±SD) age of 53.6±9.7 years were included in this study. Isometric endurance of the shoulder muscles was characterized by time and net impulse (NI), which were assessed with the patient holding a weight in the hand until exhaustion. Fatigability of the deltoid and trapezius muscles during isometric endurance test was assessed by electromyogram power spectrum median frequency (MF) slope per minute. Patients were also screened for daytime pain. Data were collected before MUA, and at 1 and 6 months postoperatively.

RESULTS

Six months postoperatively, the MF slope for the trapezius and deltoid muscles of the involved and uninvolved shoulders did not differ (P>0.05), whereas NI remained lower and endurance time was longer (P<0.05). Shoulder pain was reduced as compared to preoperative levels (on visual analog scale) 1 and 6 months postoperatively (P<0.05).

DISCUSSION

In patients with FSS, the fastest improvements in shoulder muscle NI, fatigability and pain take place in the first month after MUA; 6 months after MUA, however, NI and endurance time remained impaired for the involved shoulder. Physiotherapy should pay more attention to muscle function recovery.

LEVEL OF EVIDENCE

Level III, prospective follow-up study.

Validation of the Simple Shoulder Test in a Portuguese-Brazilian population. Is the latent variable structure and validation of the Simple Shoulder Test Stable across cultures?

BACKGROUND

The validation of widely used scales facilitates the comparison across international patient samples. The objective of this study was to translate, culturally adapt and validate the Simple Shoulder Test into Brazilian Portuguese. Also we test the stability of factor analysis across different cultures.

OBJECTIVE

The objective of this study was to translate, culturally adapt and validate the Simple Shoulder Test into Brazilian Portuguese. Also we test the stability of factor analysis across different cultures.

METHODS

The Simple Shoulder Test was translated from English into Brazilian Portuguese, translated back into English, and evaluated for accuracy by an expert committee. It was then administered to 100 patients with shoulder conditions. Psychometric properties were analyzed including factor analysis, internal reliability, test-retest reliability at seven days, and construct validity in relation to the Short Form 36 health survey (SF-36).

RESULTS

Factor analysis demonstrated a three factor solution. Cronbach's alpha was 0.82. Test-retest reliability index as measured by intra-class correlation coefficient (ICC) was 0.84. Associations were observed in the hypothesized direction with all subscales of SF-36 questionnaire.

CONCLUSION

The Simple Shoulder Test translation and cultural adaptation to Brazilian-Portuguese demonstrated adequate factor structure, internal reliability, and validity, ultimately allowing for its use in the comparison with international patient samples.

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.

Oxford Shoulder Score: cross-cultural adaptation and validation of the Turkish version

BACKGROUND

The Oxford Shoulder Score (OSS) is a questionnaire developed to evaluate patients with certain shoulder problems. This study aimed to translate and culturally adapt a Turkish version of the OSS and validate its use for assessing Turkish patients with shoulder pathology.

PATIENTS AND METHODS

OSS was translated and culturally adapted according to the guidelines in the literature. Eighty-four patients (mean age 49.26 ± 11.92 years) with shoulder problems participated. Patients completed the Turkish OSS, the Short Form 36 (SF-36), and the Shoulder Pain and Disability Index (SPADI). Internal consistency was tested using Cronbach α coefficient. Reproducibility was assessed by asking patients to complete another OSS 48 h after the first test. Correlation between the total results of both tests was determined by the Pearson correlation coefficient and ICC. Validity was assessed by calculating the Pearson correlation coefficient between the OSS and SPADI and SF-36 scores. Floor and ceiling effects were analyzed.

RESULTS

The internal consistency was high (Cronbach's α 0.92). The reproducibility tested by two different methods showed no significant difference. Correlation between the OSS and SPADI and SF-36 physical component summary score were -0.7, and 0.6, respectively (p < 0.001). There was no floor or ceiling effect in total OSS score.

CONCLUSION

The Turkish version of the OSS proved to be valid, reliable and reproducible instrument as demonstrated by high Cronbach α and Pearson Correlation Coefficients. The application and evaluation of the instrument was feasible and minimally time consuming for use in clinical trials in Turkish-speaking patients with shoulder problems.

Italian cross-cultural adaptation and validation of the Oxford Shoulder Score

BACKGROUND

The Oxford Shoulder Score (OSS) is an English-language questionnaire specifically designed to evaluate patients affected by shoulder pain. Although this scoring system has been translated into other languages, an Italian version of it is still not available. The aim of the present study was to translate, culturally adapt, and validate the Italian version of the OSS.

MATERIALS AND METHODS

We recruited 140 patients with shoulder pain caused by degenerative or inflammatory state or disorder of the shoulder. Patients completed the following questionnaires: Italian OSS, University of California, Los Angeles (UCLA) Shoulder Rating Scale, Constant-Murley shoulder assessment, and the Medical Outcome Study Short-Form 36 Health Survey (MOS SF-36). Internal consistency was tested using Cronbach coefficient alpha. Reproducibility was assessed by asking 110 patients to complete another OSS 48 hours after the first. Correlation between the total results of both tests was determined by the Pearson correlation coefficient. Validity was assessed by calculating the Pearson correlation coefficient between the OSS and the UCLA, Constant-Murley, and SF-36 assessments.

RESULTS

Cronbach alpha was 0.95. The Pearson correlation coefficient was r=0.97. With respect to validity, there was a significant correlation between the Italian OSS and the individual scores of UCLA, Constant-Murley, and SF-36.

DISCUSSION

Psychometric properties of the Italian OSS compared well with those reported for the English OSS. As demonstrated by the high values of Cronbach alpha and Pearson correlation coefficients, in accordance with the English version of the OSS, the Italian version proved to be a reliable, valid, and reproducible measure of shoulder pain perception in Italian-speaking patients.