Citations are used to document sources of information, to acknowledge prior relevant research, and to substantiate claims, and therefore play a key role in the evolution of knowledge. Citations are usually used to quantify the impact of publications and journals. Under the rubric of bibliometrics, citation counts have been incorporated into metrics intended to measure the impact of researchers, publications, journals, universities, and even countries. According to Zitt, et al. “high-cited publications (HCPs) are among the most commonly used indicators” for measuring “excellence.” Many countries are moving toward research policies that emphasize excellence. Consequently, they develop evaluation systems to identify universities, research groups, and individual researchers that can be said to be “excellent.” Lately, this was shown in a European Commission benchmarking study, in which HCPs were used as indicators for comparing the research performance of the EU countries. The HCPs have also been applied as indicators in case studies of research groups and an explorative study by Tijssen et al. concluded that these do represent useful indicators for identifying “world-class” research. As the subject of research excellence has received increasing attention (in science policy) over the last few decades, increasing numbers of bibliometric studies have been published dealing with, characterizing, and ranking HCPs in different disciplines.
In the Indian orthopedic research, there are more than 4606 global publications in the Scopus database from 2012 to 2021. It is difficult for a researcher to read all these publications, especially for those new to the field. The bibliometric technique is an efficient method for analyzing the publications in a research field and this exercise will help the research community to get the insight into the past and current research being followed by scholars in the field. These bibliometric studies of HCPs have been undertaken in the past on orthopedics research at the international level,[8,9] regional level (Latin America), and national level in Italy, Mexico, and Turkey.[11,12,13] Some bibliometric studies have been undertaken on Indian publications in orthopedic research.[14,15,16] However, the bibliometric studies analyzing high-cited Indian orthopedic publications are lacking, and hence, it was thought imperative to analyze the top-cited papers in the field of orthopedics from Indian authors, over the last two decades.
In this study, we bibliometrically analyzed and provided network visualization of the 179 HCPs on the orthopedic research from India, using Scopus database. The study provides insights into publication performances and research characteristics using select indicators. In particular, it will identify leading institutions, authors, journals, and research areas; identify collaboration patterns between countries, organizations, and authors; and identify research trends and hotspots. This will be accomplished by analyzing author keywords and HCPs.
Orthopedic publications from India were identified and downloaded from Scopus database using a search strategy on May 09, 2022. We chose Scopus data as it is one of the largest abstract and citation databases of peer-reviewed literature and provides an overview of the world's research output in the fields of science, technology, medicine, social sciences, and arts and humanities. It is an international interdisciplinary database that covers and lists more number of journals in comparison to PubMed or Web of Science, particularly in medical science.
Eligibility criteria and study selection
The search strategy used keywords “Orthopaedics” or “Orthopedics” in the field tag “Title-ABS-Key” for the search and subsequently the search was limited to publication years 2002 to 2021. (TITLE-ABS-KEY (orthopaedics OR orthopedics) AND AFFILCOUNTRY (india)) AND PUBYEAR >2001 AND PUBYEAR <2022).
The available literature was analyzed for the year of publication, affiliations, type, and source of document, funding sources, international collaborative publications (ICP), leading organizations and authors, prominent journals, publication distribution by city of publications, type of study, broad subjects and subfields of interest, and significant keywords.
All the HCPs were classified under the broad subject categories (as defined by Scopus). This is based on journal subject classification. As a result, there is an overlapping of papers under different broad subjects. In order to simplify the analysis, we have combined two broad subjects: material science and engineering that led to 83 HCPs. These 83 papers belonged to materials used for orthopedic research. For rest of the papers, we have combined three broad subjects: medicine, biochemistry, genetics and molecular biology and pharmacology, toxicology, and pharmaceutics, leading to 96 other papers. In addition, we have removed dental science as a broad subject as it does not come within the purview of this area. Since the broad subjects are overlapping, its removal does not make a difference in the output of other broad subjects mentioned in this section. Based on author keywords, the type of studies under orthopedic research was identified from these 96 remaining HCPs, and these were classified as treatment studies, clinical studies, pathophysiology studies, risk factor studies complication studies and diagnostic studies based on keywords either independently or by combining two or more keywords. In addition, based on author keywords, we have made anatomical, subspecialty, and population age group classification of papers. Out of 96 remaining, only 45 contained population age groups, and remaining cover basic research.
Certain select indicators, such as number of publications, number of ICP, number of citations and citations rate (defined as the number of citations per publication [CPP]) were used. In addition, ICP were considered as the publications with multiple authors from different countries. If the number of publications contributed by an author was more than the average number of publications by all authors, then they were considered as highly productive organizations. Similarly, if the number of publications contributed by an author was more than the average number of publications by all authors, then they were considered highly productive authors.
Some bibliometric indicators were applied to evaluate the status and citation impact of the most productive journals, countries, organizations, and authors. Social network analysis was performed to evaluate and visualize the interaction among the most productive countries, organizations, authors, and keywords using VOSviewer (Leiden University, Netherlands) Bibioshiny (K-synth Srl, University of Naples Federico II).
Overall output, impact, and funding
The search yielded 4606 records from India, and 179 (3.88%) publications received total citations ≥50. These HCPs increased from 1 in 2002 to 19 in 2014 and then decreased to 0 in 2021. The highest number of HCPs were published in 2014 (n = 19), followed by 2013 (n = 18). Of all of the years examined, 2009 had maximum number of citations (n = 4603) [Table 1]. The 179 HCPs have received 22767 citations, averaging 127.19 CPP. Of the 179 HCPs, 129 publications were in citation range 51–100, 37 in citation range 102–185, 10 in citation range 216–296, 3 in citation range 408–854, and 2 in citation range 1356–3589.
Of the 179 HCPs, 44 (24.58%) received external funding support and have received 7496 citations, averaging 113.57 CPP. The major funding agencies supporting high-cited research in this area (along with their publication output) were Council of Scientific and Industrial Research [CSIR] (9 publications); department of science and technology (DST) (7 publications); department of biotechnology (DBT), West Bengal and Bangladesh CSIR (5 publications each); DST, West Bengal (4 publications); DBT, the Indian Council for Medical Research, National Institute of Hydrology, the United States of America (USA), and National Science Foundation, USA (3 publications each); and University Grants Commission, the Defence Research and Development Organisation and Ministry of Human Resource Development (2 publications each). Of the 179 HCPs, 68.16% (122) were published as articles, 29.61% (53) as reviews, 1.68% (3) as conference papers, and 0.56% (1) as a book.
In 96 nonengineering and materials science HCPs from India, 45 contain information on population age groups identified through keywords. Among 45 HCPs, adults constitute 37 publications, followed by middle aged (25 publications), aged (19 publications), children (15 publications), and adolescents (14 publications). There is large overlapping of papers under various population age groups. The remaining 51 nonengineering papers were focused on basic research.
International collaborative research
Only 66 (36.87%) out of 179 HCPs were international collaborative publications (ICPs) and these 66 ICPs have received 7496 citations, averaging 113.58 CPP. Among the 52 foreign collaborating countries in India's high-cited research in orthopedics, USA participated in the largest number of publications, (31) followed by the U. K. (11 publications); Australia, Canada, and Germany (9 publications each); Singapore (8 publications); Brazil (7 publications); China, Italy, and South Korea (6 publications each); Sweden and Switzerland (5 publications each); and Austria, Hong Kong, The Netherlands, Poland, and South Africa (4 publications each). Among foreign collaborating countries, Sweden registered the highest citation impact per publication (324.0), followed by Austria (101.25), the USA (99.52), Singapore (94.75), and Poland (92.0).
The largest number and share of publications (27 papers and 15.08 share) were published by the authors from Delhi, followed by Chennai (18 publications and 10.06% share); Bengaluru and Mumbai (14 publications and 7.82% share each); Chandigarh (9 publications and 5.03% share); Hyderabad (8 publications and 4.47% share); Kolkata (5 publications and 2.79% share); Pune (3 publications and 1.68% share); Rohtak and Trivandrum (2 publications and 1.12% share each); and Lucknow, Bhopal, and Shimla (1 publication, 0.56% each). However, Hyderabad registered the highest impact of CPP (547.0), followed by Bengaluru (172.79), Delhi (159.44), Shimla (112.0), Kolkata (109.6), Pune (108.0), Rohtak (102.0), Chennai (88.67), Mumbai (85.43), Chandigarh (72.44), Trivandrum (60.5), Bhopal (56.0), and Lucknow (54.0).
Type of studies
Of the 179 HCPs, 83 publications (46.37%) were focused on materials research used in orthopedics. The remaining 96 publications (53.63%) were further classified as treatment studies contributed the largest share of publications (24.58%, 44), followed by clinical studies (8.38%, 15 publications), pathophysiology (5.59%, 10 publications), risk factors and diagnostics (2.79%, 5 publications each), and complications (0.56%, 1 publication).
In terms of anatomical location, the major focus of HCPs was on Spine (10 publications, 5.59%) followed by knee and leg (8 publications, 4.47%); hip and thigh (6 publications, 3.35%); cervical spine (5 publications, 2.79%); wrist and hand and pelvis and acetabulum (3 publications, 1.68% each); elbow and forearm (2 publications, 1.12%); and sacrum and coccyx, lumbar and thoracolumbar spine (1 publication, 0.56% each). In terms of impact, lumbar spine registered the highest citation impact per publication (252.0), followed by sacrum and coccyx (178.0), knee and leg (85.38), hip and thigh (84.50), elbow and forearm (84.0), spine (78.0), cervical spine (76.40), pelvis and acetabulum (69.0), wrist and hand (66.0), and thoracolumbar Spine (67.0).
Subject-wise distribution of papers
Broad subject-wise distribution
The highest number of publications (77 publications and 41.90% share) was contributed by materials science, followed by medicine (73 publications and 40.78% share); engineering (51 publications and 28.49% share); biochemistry, genetics, and molecular biology (29 publications and 16.20% share); and pharmacology, toxicology, and pharmaceuticals (10 publications and 5.59% share). In terms of impact, materials science and engineering individually registered the highest citation impact per paper (246.96 and 98.35) and medicine and biochemistry, genetics and molecular biology had the least (86.50 and 90.34) [Table 2].
Infection and pediatric research accounted for the largest share of publications (7.82%, 14 publications each), followed by spine (6.15%, 11 publications), oncology (4.47%, 8 publications), arthroplasty (2.79%, 5 publications), trauma (1.68%, 3 publications), peripheral nerves (1.12%, 2 publications), and metabolic (0.56%, 1 publication). In terms of impact, metabolic research registered the highest citation per publication (116.0), followed by infection (99.30), peripheral nerves (98.0), arthroplasty (90.4), spine (85.54), pediatric (84.36), trauma (69.0), and oncology (68.0).
A total of 2983 keywords appeared in 179 HCPs. The most keywords occurred once, 413 keywords occurred two times, 285 keywords occurred 2–5 times and 107 keywords occurred 6–10 times. The results indicated that “hydroxyapatite” (n = 40); “biocompatibility” (n = 35); “bone” (n = 27); and “biomaterial,” “orthopedic surgery,” and “surface property” (n = 21) were the most popular keywords in the field. A total of 67 keywords with a frequency of more than four were chosen for the co-occurrence network. The co-occurrence network map displayed in [Figure 1] was constructed with the help of VOSviewer. All these 67 keywords were spread over 5 clusters and each cluster presented with a certain color. The significant keywords cloud map is displayed in Figure 2.
Top most productive organizations
A total of 659 organizations unsteadily participated in 179 HCPs: 579 organizations contributed 1 publication each, 74 organizations contributed 2–7 publications each, 2 organizations contributed 8 publications each, and one organization contributed 11 publications. The top 25 organizations contributed 3–11 publications and these together contributed 63.13% (113 publications) share in India's publications and 60.63% (13,804) share in India's citations. On further analysis, it was observed that 8 organizations contributed more than the average publication productivity (4.52) of all top 25 organizations; and 4 organizations registered average CPP and RCI above the average (122.16 and 0.96) of all 25 organizations. [Table 3] lists the top 3 most productive and 3 most impactful organizations.
Collaborative linkages among top 25 organizations
The collaboration linkages among the top 25 organizations [Figure 3] varied from 0 to 52, with the highest collaborative linkages depicted by All India Institute of Medical Sciences (AIIMS)-New Delhi (52 linkages), Amrita Institute of Medical Sciences (AIMS), Kochi (26 linkages), IIT, Madras (21 linkages), and CGCRI-Kolkata (18 linkages). The individual collaborative linkages among any two organizations are generally weak and varied from 1 to 4. Among these organizations the “CGCRI-Kolkata – WB Univ. Animal and Fishery Science, Kolkata” collaborated in the highest number of publications (n = 4), followed by 15 other pairs (with 1 linkage each).
Top most productive authors
In all, 2159 authors participated in 179 HCPs. The top 43 most productive Indian authors contributed 2–7 publications and together contributed 112 publications and 10820 citations, constituting 62.57% and 47.52% share of total Indian publications and citations received by them. On further analysis, it was observed that 13 authors contributed more than the average publication productivity (2.60) of all top 43 authors; and 18 authors registered average CPP and relative citation index above the average (96.61 and 0.76) of all 43 authors. [Table 4] lists the top 3 most productive and 3 most impactful authors. The list of impactful publications of the top 3 most impactful authors is available as an appendix [https://links.lww.com/APMD/A7], for a reference.
Collaborative linkages among top 43 authors
The collaboration linkages among the top 43 authors varied from 2 to 78, with the highest collaborative linkages (78) registered by P. Sancheti (Pune), followed by D. Lahiri (Roorkee) (26), K. Chatterjee (Bengaluru) (20), and S. K. Nandi (Kolkata) (14). The individual collaborative linkages among any two authors were generally weak and varied from 1 to 4. Among these authors are “K. Chaterjee – S. Kumar (Indian Institute of Science [IISc]-Bang)” and “H. Haleem – A. Javaid (Jamia Millia Islamia)” who collaborated in the highest number of publications (n = 4), followed by “S. K. Nandi – B. Kundu” (WBUAFS-CGCRI) (n = 3) and 26 other author pairs (with n = 2).
Most productive journals
The 179 HCPs were published in 119 journals. The distribution of HCPs by reporting journals is widely scattered. For instance, as many as, 91 journals published just 1 publication each, 11 journals published 2 publications each, 9 journals published 3 publications each, 2 journals published 4–5 publications each, 2 journals published 7 publications each, and 1 journal published 8 publications.
The top 24 journals published 2–8 publications and together published 77 publications, accounting for 43.75% share in India's total journal publications. Materials Science and Engineering C had the highest number of publications (n = 8), followed by Acta Biomaterialia and Journal of Clinical Orthopedics and Trauma (n = 7 each), Journal of Mechanical Behavior of Biomedical Materials (n = 5), Ceramics International (n = 4), ACS Applied Materials and Interfaces, Spine, Materials Chemistry and Physics and International Journal of Macromolecules (n = 3 each), etc., European Polymer Journal registered the highest citation per publication (404.5), followed by Indian Journal of Medical Research (198.9), Spine (149.0), Journal of Orthopedic Research (139.50), Science and Engineering C (120.0), International Journal of Macromolecules (112.0), Journal of Clinical Orthopedics and Trauma (98.71), ACS Applied Materials and Interfaces (97.33), and Nanotechnology (93.0).
The limitation of the present study is that the data from only a single search engine (Scopus) were used. Therefore, some of the publications that are not present in this database are missed and may also mitigate the publications in some nonmedical journals, for example, sensors international. However, we chose to use the data from Scopus, as it is the largest database and provides the maximum useful bibliometric information, as compared to the other databases such as WoS and Cochrane. Furthermore, mixing the information and data derived from the other sources would have been heterogeneous making the scientometric analysis complex and inaccurate.
We believe that this approach of citation analysis provided an opportunity to retrieve the most important articles on Indian orthopedics and describes the trends in India's orthopedics research. Our analysis provided an insight into the citation frequency of HCPs that help recognize the quality of the works, and the trends steering the study of orthopedics.
The present scientometric approach of citation analysis provided us an opportunity to retrieve the most important articles on Indian orthopedics and describe the trends in India's orthopedics research. We believe that this analysis provides useful insight into the citation frequency of high-cited cited articles published in Indian orthopedics to help recognize the quality of the works, discoveries, and the trends steering the study of orthopedics.
At the institution level, the IIS, Bengaluru (11 papers) is the most productive organization, and the Vellore Institute of Technology (VIT) received the highest total citations (4011 citations), and also the highest average citations per paper (1002.75). At the author level, K. Chatterjee (of IISc-Bengaluru) was the most productive author (7 papers) and received the highest citations (563) whereas P. Mukerjee (CGCRI-Kolkata) had the highest average citations per paper (173.0). At the journal level, Materials Science and Engineering Cis the most productive (8 papers) and European Polymer Journal registered the highest average citation per paper (404.5).
The interaction among productive countries/territories, organizations, authors, and keywords were analyzed. For organizations, AIIMS-New Delhi (52 linkages), AIMS, Kochi (26 linkages), IIT, Madras (21 linkages), and CGCRI-Kolkata (18 linkages) had the highest collaboration intensity. However, among the institutions, “CGCRI-Kolkata – WB Univ Animal and Fishery Science, Kolkata” collaborated in the maximum number of publications (n = 4). For authors, P. Sancheti (Pune) (78), D. Lahiri (Roorkee) (26), K. Chatterjee (Bengaluru) (20), and S. K. Nandi (Kolkata) (14) had the highest collaboration intensity. However, “K. Chatterjee – S. Kumar (IISc-Bang)” and “A. Haleem – M. Javaid (Jamia Millia Islamia)” collaborated in the highest publications (n = 4).
The original research articles were further classified into broad subjects such as materials science (41.90%), medicine (40.78% share), and engineering (28.49% share) and by subspecialty as pediatric and infection (14 papers each), spine (11 papers), and oncology (8 papers). The analysis of HCPs suggests that the studies related to treatment, clinical, and pathophysiology were the most researched areas in Indian orthopedics. By anatomical location, the analysis suggested that the most focused locations are spine, knee and leg, and hip and thigh.
This scientometric analysis was done over two decades and has been the most elaborate study done on a similar topic, so far. We observed that the older articles (from 2002 to 2014) received more citations than the newly published articles (from 2014 to 2021) [Table 1]. It is understood that some of the recently orthopedic publications might also get sufficient citations in the future to be considered as HCPs. Authors from across the globe have recently started analyzing the top orthopedic-related articles published in their countries or a particular journal.[9,10,11,12,13,14,15,16] Mavrogenis et al. have analyzed the top-100 articles published in the International Orthopaedics, and Vishwanathan et al. studied the top-50 cited articles that were published in the Journal of Clinical Orthopaedics and Trauma and reported that a majority of top-cited articles were related to trauma and adult reconstruction. Whereas, some of the other authors have analyzed the best papers from their own countries, namely, Urrutia et al. from Latin America, Yalcinozan from Turkey, Piolanti et al. from Italy, Berebichez-Fridman and Berebichez-Fastlicht from Mexico, and Patralekh et al. from India. All the above-mentioned studies were focused on the publications in the last decade and a particular journal or from a country. Karlapudi et al. reported a steady increase in the orthopedic publications during the last decade and the Journal of Clinical Orthopaedics and Trauma was the leading Indian journal to publish these articles. Similar to our findings, they found that the institutes from New Delhi contributed the maximum publications and also received maximum citations.
It is interesting to note that the HCPs were maximally contributed by the engineering institutes than the medical institutes, and were mostly focused on biomaterials from engineering perspectives. Hence, a close tie-up and collaboration are required between the medical professionals and their counterparts, “bio-engineers,” to emerge with high-quality research and innovations in the field of orthopedic surgery. Most of the significant collaborations in this study are observed between medical organizations, with the exception of collaboration between IIT-New Delhi and AIIMS-New Delhi.
The major limitation of the present study is that the data from only a single search engine (SCOPUS) were used. Therefore, some of the publications that are not present in this database are missed. However, we have chosen to use the data from SCOPUS, as it is the largest database and provides the maximum useful bibliometric information, as compared to the other databases such as WoS and Cochrane. Furthermore, mixing the information and data derived from the other sources would have been heterogeneous making the scientometric analysis complex and inaccurate.
In this bibliometric study, we found 4606 publications on Indian orthopedic research as listed in the Scopus database during 2002–21. Only 179 publications (3.88%) received more than 50 citations. Delhi was the epicenter of research and publication activities. This study provides insights into publication performances and research characteristics using select indicators and has identified the leading institutions, authors, journals and research areas, collaboration patterns between countries, organizations, and authors. Moreover, it also identifies the research trends and hotspots, by analyzing author keywords and HCPs. We noticed that the majority of HCPs were contributed by India's well-known engineering and technological institutes and were focused on the usefulness of existing identified biomaterials or new upcoming materials related to orthopedics. A large portion of research (as reflected in keyword frequency) was related to biomaterials. In order to diversify India's research on orthopedics, we believe that there is an urgent need to expand international collaboration which will help to improve both research output and research impact and quality.
Conflicts of interest
There are no conflicts of interest.
Institutional ethical committee approval
Being a study based on the literature search and not involving any human participation or intervention, ethical committee approval was not needed.
Declaration of patient consent
The authors certify that he has obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that his name and initials will not be published, and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
All the four authors contributed equally in conceptualizing the study, literature search, statistical analysis of the data, manuscript writing and editing.