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Publication Trends and Hot Spots in Subacromial Impingement Syndrome Research: A Bibliometric Analysis of the Web of Science Core Collection

Authors Ge M, Zhang Y, Li Y, Feng C, Tian J, Huang Y, Zhao T

Received 9 November 2021

Accepted for publication 12 March 2022

Published 28 March 2022 Volume 2022:15 Pages 837—856

DOI https://doi.org/10.2147/JPR.S348528

Checked for plagiarism Yes

Review by Single anonymous peer review

Peer reviewer comments 3

Editor who approved publication: Dr Houman Danesh



Meng Ge,1,2,* Yuan Zhang,2,3,* Yanlei Li,1,2,* Chenchen Feng,1,2,* Jinlong Tian,1,2 Yazeng Huang,1,2 Tingxiao Zhao1

1Center for Plastic & Reconstructive Surgery, Department of Orthopedics, Zhejiang Provincial People’s Hospital (Affiliated People’s Hospital, Hangzhou Medical College), Hangzhou, Zhejiang, 310014, People’s Republic of China; 2Bengbu Medical College, Bengbu, People’s Republic of China; 3Center for General Practice Medicine, Department of Rheumatology and Immunology, Zhejiang Provincial People’s Hospital (Affiliated People’s Hospital, Hangzhou Medical College), Hangzhou, Zhejiang, 310014, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Tingxiao Zhao; Yazeng Huang, Center for Plastic & Reconstructive Surgery, Department of Orthopedics, Zhejiang Provincial People’s Hospital (Affiliated People’s Hospital, Hangzhou Medical College), Shangtang Road 158#, Hangzhou, Zhejiang, 310014, People’s Republic of China, Email [email protected]; [email protected]

Background: In recent years, the research on subacromial impingement syndrome (SIS) has gradually increased. Although the research directions are diverse, the overall research status and trend are not clear.
Objective: The aim of our study was to use bibliometric analysis to identify the trends in SIS-related research and to analyze the most highly cited scientific publications on SIS.
Methods: All data were retrieved from the Web of Science Core Collection database, and the year of publications, countries, journals, institutions and total number of citations were extracted and analyzed. The results related to countries, institutions and keywords were then analyzed using VOSviewer software and bibliometrics online analysis platform. And, we also identified the 100 most cited articles on SIS.
Results: A total of 548 articles related to AIS were identified. The frequency of publication on SIS has increased substantially over time. Among all countries, Turkey has contributed the most publications on SIS (n=118). The institution with the most articles was Istanbul University (n=17). Journal of Shoulder and Elbow Surgery topped the list of journals and has published 19 SIS-related publications. The hotspot of research changed from the former arthroscopic surgery to physical therapy and rehabilitation.
Conclusion: The scientific research on SIS has rapidly expanded in recent years. This study represents the first bibliometric analysis of SIS, gives us a systematic and comprehensive summary into the development of SIS.

Keywords: subacromial impingement syndrome, SIS, bibliometric analysis, research trends, VOSviewer, Web of Science

Introduction

Shoulder pain occupies a large portion of the orthopedic field, ranking third in musculoskeletal pain.1 Subacromial impingement syndrome (SIS) is the most common cause of shoulder pain, accounting for 44% to 65% of all complaints of shoulder pain lesions, with the age of onset mostly in the 40s and 50s.2–5 In 1972, Neer first proposed the concept of SIS and explained it in detail5. The main pathological mechanism of SIS is structural narrowing of the subacromial space, and its etiology includes a spectrum of disorders ranging from subacromial bursitis and rotator cuff tendinopathy to partial and total rotator cuff tears.6–8

The main clinical manifestations are upper arm supination, abduction, pain after internal rotation, decreased mobility, and loss or diminished arm strength and function.9–12 Because of the diverse and complex etiology of SIS, a thorough history and physical examination, combined with appropriate imaging, are required for a definitive diagnosis, including Neer’s sign, Hawkins-Kennedy sign, and pain arc sign.13,14 Some studies have also used “shoulder arthroscopy” as the “gold standard” for the diagnosis of SIS, but because of its invasive nature it is often used for surgical treatment rather than as a routine preoperative examination.15–17 The treatment of SIS is aimed at reducing pain and restoring function of the shoulder joint. Conservative treatment includes functional exercises, medication, closure therapy, the use of osteo-biological materials and injection therapy. Unlike conventional injection therapy, some scholars have also noted that simultaneous corticosteroid injection into the subacromial bursa and the long head of the biceps tendon sheath is safe and effective, While ensuring short-term efficacy, it also prolongs the duration of symptom relief. Surgical treatment includes traditional open surgery and arthroscopic surgery.18–24

Up to now, research on SIS has expanded dramatically to include study of its pathogenesis, clinical manifestations, radiological evaluation, and surgical and physical treatments, and a large number of SIS publications have been published annually.25–28 In recent years, bibliometric analysis as a reliable statistical method to quantitatively and qualitatively assess research status and trends in a field of study. This analysis method has been widely used in the orthopedic field.29–31 However, To the best of our knowledge, up to date, there is no targeted bibliometric analysis of global scientific research of SIS. Thus, the aim of the current study was to conduct a bibliometric study to summarize and analyses the progress and trends of SIS.

Materials and Methods

Search Strategy

All data for this study were obtained from articles indexed in the Web of Science Core Collection database. The search was conducted on June 25, 2021. The search strategy was as follows: Title = (subacromial impingement syndrome OR shoulder impingement syndrome OR impingement syndrome of the shoulder OR acromion impingement syndrome) AND Title = SIS AND Document type (article OR review) AND Language = English AND Time span = 1900 to 2021.

Tools

VOSviewer, bibliometrics online analysis platform and Microsoft Excel 2016 were used to analyze the data. VOSviewer is a software tool based on Java that assists with visualization and analysis of bibliometric data. We used this software and bibliometrics online analysis platform to visualize networks of authors, countries, institutions, co-citation of references, and co-occurrence of keywords.

Data Extraction

After devising the search strategy, 2 authors (G.M. and Z.T.X.) extracted the articles and bibliometric indicators independently, and the differences were discussed until consensus was achieved. All data were downloaded from the Web of Science Core Collection database, and VOSviewer and Microsoft Excel 2016 were used to extract and analyze article data, including authors, journals, institutions, countries, total citations, and research trends.

Result

Publication Trend

A total of 548 articles on SIS research were identified in the Web of Science Core Collection database. (Supplement Table 1) A trend toward an increasing number of publications between 1972 and 2021 was noted (Figure 1A). Quantitative analysis revealed that global research on SIS has rapidly increased in the past 20 years, with publications increasing rapidly from 80 between 2006 and 2010 to 157 between 2011 and 2015. This indicates that SIS has received increasing attention, and further research on SIS is ongoing.

Figure 1 Overview of publications relating to subacromial impingement syndrome (SIS). (A) Number of publications and citations from 1981 to 2021. (B) Geographic map showing sources of publications. (C) Top 10 countries publishing on SIS. (D) Network visualization map depicting international collaborations investigating SIS.

Country Distribution

The publications were drawn from 48 different countries. Among these countries, the Turkey published the largest number of publications (n=118), followed by United States (n=100), United Kingdom (n=47), Germany (n=27) and Brazil (n=25) (Figure 1B and C). The VOSviewer software was used to analyze the network visualization of co-authorship relationships between countries. The visual analysis shows that the Turkey has always been the center of SIS research in the world, and United States, United Kingdom, Germany, and Brazil have been found to be potential research powers. (Figure 1D).

Institution Distribution

A total of 726 institutions were represented in the published papers. The top 10 institutions were Istanbul University (Turkey; n=17), Hacettepe University (Turkey; n=15), Keele University (United Kingdom; n=14), Virginia Commonwealth University (United States; n=10), Aarhus University Hospital (Denmark; n=9), Federal University of Sao Carlos (Brazil; n=8), University Laval (Canada; n=7), Dokuz Eylul University (Germany; n=7), Baskent University (Turkey; n=7), University of Oregon (United States; n=6), National Taiwan University (Republic of China; n=6), and Marmora university (Canada; n=6) (Figure 2A). Publications from Virginia Commonwealth university were cited the most, with a total of 1003 times, followed by The University of Oregon with 932 citations and Arcadia University with 917 citations (Figure 2B).

Figure 2 Highest impact institutions publishing on SIS. (A) The 10 institutions with the most publications. (B) The 10 institutions with the most citations. (C) Network visualization map demonstrating institutional collaborations related to SIS.

With respect to co-authorship relationships between institutions examined in our network visualization analysis, Virginia Commonwealth University had the highest total link strength (n=471), followed by Arcadia University (n=423), The University of Oregon (n=420) and Keele University (n=326). In this analysis, the thickness of the line reflects the frequency of co-authorship collaboration among the institutions. Only institutions with a minimum of 13 articles were included, and a total of 65 institutions met this threshold. Hacettepe University had closely collaborations with Baskent University and National Taiwan University. Pittsburgh University had massive collaborations with Duke University, Texas Scottish Rite Hospital for Children and Pain Relief & Physical Therapy (Figure 2C).

Journal of Publication

The 548 publications were published in 215 academic journals. The top 20 Journals published 40.1% of all publications (Table 1). The top 3 journals were: Journal of Shoulder and Elbow Surgery, Bone and Joint Surgery-American Volume, BMC Musculoskeletal Disorders. Journal of Bone and Joint Surgery-American Volume had the highest number of citations. The Journals with more than 10 of the publications on SIS, mean impact factor (IF) was 4.604, indicating that the included studies were highly reliable.

Table 1 Journals Publishing Most on Subacromial Impingement Syndrome

Keywords Analysis and Research Interest

Keywords from publications on SIS research were analyzed using a co-occurrence network analysis tool in the VOSviewer software. In this analysis, the minimum number of occurrences of a key word in publication was set at 15. A total of 48 keywords were identified, and classified into 3 clusters: “Treatment,” “Symptoms,” and “Diagnosis,”. In the treatment cluster, the most popular keywords were “acromioplasty,” “arthroscopic surgery,” and “decompression.” In the symptoms cluster, the most popular keywords were “arm,” “exercise,” “kinematics,” and “manual therapy,” In the Diagnosis cluster, the most popular keywords were “corticosteroid injectoir,” “disability,” “double-blind,” and “efficacy.” (Figure 3A)

Figure 3 Keyword analysis. (A) Network visualization map showing cluster analysis of keywords associated with SIS. Different colours represent different clusters, red for treatment cluster, green for symptoms cluster and blue for diagnosis cluster (B) Network visualization map showing evolution of keyword frequency over time. Colors were assigned according to the average year in which keywords appeared in articles.

To further understand the dynamic change of research topic, we evaluated the evolution of the top most frequent key words in the periods (Figure 3B). Colors were assigned according to the average year in which keywords appeared in articles. For instance, purple keywords appeared earlier than yellow keywords. In the early stage of SIS research, the “rotator cuff,” “rehabilitation,” “arthroscopic surgery” and “acromioplasty,” were the main hotspots. Recent trends showed that the words “exercise,” “pain,” “manual therapy,” and “physiotheraphy” increased in popularity.

The 100 Most-Cited Articles

The top 100 most-cited publications on SIS identified in our study were published between 1972 and 2021 (Table 2).5–7,9,10,12,14,15,18,19,21,22,32–119 The publishing period responsible for the largest number of these studies was 2006 to 2010 with 26 articles, followed by 2011 to 2015 with 25 articles (Figure 4A).

Table 2 The Top 100 Most-Cited Articles on Subacromial Impingement Syndrome

Figure 4 Analysis of the top 100 most-cited publications on SIS. (A) Year of publication. (B) Distribution of publications by country of origin. (C) Institutions with more than one publication. (D) Publication topics.

Twenty-two different countries were identified as origins of these 100 publications, authors from the United States contributed to 39 articles, followed by United Kingdom with 9 articles, Canada with 7 articles, Turkey with 6 articles, Germany with 5 articles, Netherlands with 4 articles, Sweden with 4 articles, Finland, Brazil, and China with 3 articles, respectively (Figure 4B).

The Chelsea & Westminster Hospital contributed 4 publications out of the 100, the highest among the institutions represented, followed by Arcadia University with 3 articles (Figure 4C).

Overall, 45 different journals were represented on the list of the 100 most cited publications. Journal of Bone and Joint Surgery-American Volume was the most popular journal, which was responsible for 9 articles and 2737 total citations. This was followed by Journal of Shoulder and Elbow Surgery with 8 articles and 603 total citations. American Journal of Roentgenology, Clinical Orthopaedics and Related Research, and Journal of Orthopaedic & Sports Physical Therapy with 6 articles. (Table 3).

Table 3 Top 5 Journals Publishing the 100 Most-Cited Articles on Subacromial Impingement Syndrome

With respect to authorship, Michener, L. A. contributed 6 articles, followed by Karduna, A. R. with 4 articles, Lewis, J. S., and Timmons, M. K. with 3 articles respectively (Table 4).

Table 4 Top 4 Authors Contributing to the 100 Most-Cited Articles on Subacromial Impingement Syndrome

The most common research focuses were Physical Examination (25 articles), followed by Conservative Treatment and Clinical Description (18 articles) Imaging Findings (11 articles), Diagnosis (9 articles) (Figure 4D).

Discussion

Subacromial impingement syndrome is one of the most common causes of shoulder pain and is associated with a large number of shoulder injuries.1–3 Patients often suffer from pain that severely affects the function of the shoulder joint and can even lead to disability, which shows that research on subacromial impingement syndrome is crucial.4–7 Currently, research on SIS has expanded dramatically to include study of its pathology, clinical presentation, natural history, radiological evaluation, and management, and a large number of SIS publications have been published annually. Although the number of studies was sizable, a vacancy of integral analysis of research hot spots is imminent. Therefore, we used bibliometric mapping in the present study to achieve the visualization of the analysis results of SIS research from 1972 to 2021. The VOSviewer, bibliometrics online analysis platform and Microsoft Excel 2016 were used to carry out our survey. This study intuitively showed the research framework, overall knowledge structure, research hotpot, and development trends of the field of SIS, through integrated analysis of the content and external features of research literature. Hopefully, this study will help scientific researchers and surgeon better understand the research status and trends, determine future research direction.

Publication Trends in the SIS Scientific Literature

There has been a rapid growth in SIS-related publications in the last 20 years. The total publications of Turkey and citations of United States ranked first of all the countries, suggesting that Turkey and United States dominates studies of SIS. With respect to institutional contributions, Istanbul University published the most contributing 17 articles and Virginia Commonwealth university ranked first in the total citations, reflecting both the importance and leading role of the institutions in SIS.

Journal of Bone and Joint Surgery-American Volume, Journal of Shoulder and Elbow Surgery, American Journal of Roentgenology, Clinical Orthopaedics and Related Research and Journal of Orthopaedic & Sports Physical Therapy are the top 5 productive journals on SIS, indicating that there will be more high-quality publications on this topic to be published on these journals. Authors interested in SIS research should pay more attention to these journals.

Research Focuses

Keyword analysis results indicated the shoulder pain, rotator cuff injury, rehabilitation, and exercise were the clustering centers of keywords, and the research hotspots gradually changed with the progress of time, from the initial surgical treatment and injury mechanism to conservative treatment and patient prognosis. For example, the early keywords appearing more often are arthoscopic surgery, acromioplasty, rotator cuff tears, while the recent keywords are mostly manual therapy, exercise, corticosteroid injection, disability, and efficacy.

The Most Influential Articles

The most cited publication in SIS was the classic 1972 paper in the American Volume of Journal of Bone and Joint Surgery by Neer5 “Anterior acromioplasty for the chronic impingement syndrome in the shoulder: a preliminary report,” that first introduced the concept of anterior impingement syndrome, repeated impingement of the greater tuberosity of the humerus with the rostral shoulder arch during shoulder pronation and abduction, resulting in subacromial bursa inflammation, rotator cuff tissue degeneration, or even tearing, causing shoulder pain and impaired mobility, which is a general term for anterior or anterolateral superior shoulder pain caused by a combination of factors alone or in combination. In this article, they detail the anatomical findings and rationale, indications, techniques and preliminary results related to anterior capsuloplasty performed since 1965 at the Columbia University College of Physicians and Surgeons and New York Orthopaedic Hospital.

A study published by Michener et al from 2003 was the second most-cited article.6 In this study, they detailed the anatomy of subacromial impingement syndrome, which they found to be the most common cause of shoulder pain, with altered glenohumeral and scapular kinematics, increased anterior and superior displacement of the humeral head and decreased posterior tilt, external rotation and superior rotation. Weakness or fatigue of the muscles controlling these joints, increased flexion of the thoracic and cervical spine, and altered shoulder and lumbar posture have also been shown to be present in patients with SIS. Thus, they point out that postural, kinematic and muscular changes can directly or indirectly alter the dimensions of the subacromial space and the relationship to structures within the subacromial space. Changes in these relationships can also be brought about by architectural deviations in the boundaries of the subacromial space. These multiple factors usually appear in some combination, rather than as a single factor appearing alone. They also look to the future, all patients with SIS should be evaluated for a combination of all anatomical and biomechanical factors in order to design a treatment plan with the best chance of success, and future research needs to further elucidate the mechanisms of SIS and the relationships between the multiple factors implicated in this disorder.

“Shoulder function and 3-dimensional scapular kinematics in people with and without shoulder impingement syndrome” by McClure et al in 2006 was the third most-cited article.7 This purpose of this study was to compare 3-dimensional scapular kinematics, shoulder range of motion, shoulder muscle force, and posture in subjects with and without primary shoulder impingement syndrome. The author recruited Forty-five subjects with impingement syndrome were and compared with 45 subjects without known pathology or impairments matched by age, sex, and hand dominance. They measured shoulder motion and thoracic spine posture and use a dynamometer to measure the force of the muscle. An electromagnetic motion analysis system was used to capture shoulder kinematics during active elevation in both the sagittal and scapular planes as well as during external rotation with the arm at 90 degrees of elevation in the frontal plane. In the end they found Scapular upward rotation and clavicular elevation were slightly greater in the impingement group during flexion and slightly greater posterior scapular tilt and clavicular contraction during scapular plane elevation compared to the control group. The range of motion and force was smaller in all directions in the impingement group compared to the control group. There was no difference in resting position between the two groups.

The most recent publication in our list was by Michener published in 2013 and titled “Supraspinatus tendon and subacromial space parameters measured on ultrasonographic imaging in subacromial impingement syndrome”.18 This study indicates that the supraspinatus tendon is thicker and occupies a greater proportion of the acromiohumeral distance (AHD), supporting an intrinsic mechanism for the etiology of acromioclavicular impingement syndrome. The extrinsic mechanism of tendon compression is also supported theoretically, but future imaging studies will need to confirm direct compression accompanied by elevation. In addition, they found that treatment strategies to reduce tendon thickness could reduce symptoms, and if it can be proven that the pain is indeed caused by tendon compression, surgical intervention to increase subacromial clearance could be considered to achieve a cure.

Limitations

This study provided bibliometric information related to SIS extracted from Web of Science Core Collection database. Although this analysis was relatively comprehensive and objective, it had several limitations. First, some of influential articles that were not included in this database, so they were excluded from our study. Second, our search criteria were limited to articles in English, we might have missed out some of high-impact articles written in other languages.

Conclusion

This bibliometric analysis showed that there is a growing trend both in published articles related to SIS in the last 20 years. Turkey has contributed the most to the SIS literature. Istanbul University, Hacettepe University, Keele University are the top three institutions. Journal of Shoulder and Elbow Surgery, Journal of Bone and Joint Surgery-American Volume, BMC Musculoskeletal Disorders are the top three journals publishing on this topic. Conservative treatment and physical testing have been the focus of recent research. Besides, these 100 most cited papers provide an important reference for future researchers.

Disclosure

The authors report no conflicts of interest in this work.

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