Trends of the publications of platelet-rich plasma use in osteoarthritis knee – A PubMed and Scopus bibliometric analysis

INTRODUCTION

Platelet-rich plasma (PRP) is a hot topic among orthopedic surgeons and has emerged over the past decade as a potential treatment options for various orthopedic conditions.^[1,2] The positive role of PRP in favoring cartilage anabolism, decreasing catabolism, and other anti-inflammatory effect on the synovium and cartilage has been demonstrated in various in vivo and in vitro studies;^[3,4] and this pre-clinical research has translated to clinical research over the past decade and various randomized controlled trials (RCTs) and meta-analysis have positively supported the use in early osteoarthritis (OA) knee.^[5,6] A large number of research studies related to PRP and OA have been published in the past two decades due to the huge clinical demand for such treatments. To date, there has not been any bibliometric analysis on PRP use in OA knee.

The aim of the present study was to perform bibliometric analysis of research articles published in this field and analyze the journals, authors, collaboration network, and countries of research involved in both pre-clinical studies and clinical studies. We used PubMed and Scopus to complement each other to fill gaps in the information. This will enable in choosing the right journal for the article type, identify the authors involved in this research, enable to analyze the number and type of each research, and hence better summarize the trends in publications pertaining to PRP use in OA knee.

MATERIALS AND METHODS

RESULTS

A total number of 921 documents were retrieved from the PubMed database, whereas for Scopus, it was 1309. The documents were published in 347 and 526 different sources for PubMed and Scopus, respectively. The various document types included the clinical studies, RCT, animal studies, in vitro studies, case reports, meta-analysis, and reviews [Table 2].

The highest number of documents was received in the year 2020 for Scopus (n = 214) as well as for PubMed (n = 138). The comparative time evolution of annual scientific production based on the number of documents for PubMed and Scopus is shown in [Figure 1]. It can be seen that the number of articles published before 2001 was <5. It also clearly depicts that the interest has grown among the research community over the past 10 years.

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Figure 1:

Annual scientific production from Scopus and PubMed.

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Analysis of authors

The total authors were 3857 and 5059 in PubMed and Scopus data, respectively. The authors of single-authored documents were 33 and 74 and that of multi-authored were 3824 and 4985 for PubMed and Scopus, respectively. The authors per document were 4.18 and 3.86 from PubMed and Scopus, respectively.

Kon E emerges to be the leading author in both the databases with the maximum number of documents (n = 30 for PubMed and n = 29 for Scopus) published in this field. The list is followed by Filardo G, Cole BJ, Sánchez M, and Di Matteo B [Figure 2] for both the databases (Supplementary material Part 2 for analysis of Top-Author’s Production over time).

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Figure 2:

Top 20 relevant authors with publications in this field.

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Authors collaboration network

[Figure 3] shows the coauthorship network of the authors for PubMed and Scopus. The clusters of authors’ collaboration were almost similar for both the databases. The red cluster represents the team of Kon et al. (Italian group of authors), the blue cluster has Sanchez et al. (Spanish authors), the green cluster represents Cole et al. (Chicago, USA), and so on.

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Figure 3:

Authors collaboration network (a) PubMed and (b) Scopus. The colors represent the different clusters obtained using Louvain algorithm.

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Analysis of journals

The most prominent journals in terms of number of documents and influential in terms of H index and citations are tabulated in [Table 3 and in Figure 4].

(Part 3 supplementary materials)

Table 3: Top 10 journals publishing PRP and OA knee relevant studies.

Journal name	Total documents in PubMed	Total documents in Scopus	Total citations in Scopus	H-index
Arthroscopy – Journal of Arthroscopic and Related Surgery	54	50	1837	18
American Journal of Sports Medicine	46	48	2366	19
Osteoarthritis and Cartilage	25	31	2143	18
Knee Surgery, Sports Traumatology, Arthroscopy	24	25	1620	18
BioMed Research International	15	16	326	9
PM&R: The Journal of Injury, Function and Rehabilitation.	15	15	274	6
The Journal of Knee Surgery	14	4	98	3
International Orthopaedics	13	5	136	4
Arthritis and Rheumatology	12	12	146	3
Orthopaedic Journal of Sports Medicine	11	20	188	6

Green indicates the top journal and yellow indicates second in the respective parameter

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Figure 4:

Top 10 journals based on total citations, citations per document, and documents from Scopus.

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Conceptual structure

The conceptual structure was created using multiple correspondence analyses (MCAs) method of the network of terms extracted from title, abstracts, and authors’ keywords. It gives us an idea of the links between concepts through the co-occurrences of the terms. It helps in identifying the similar group of studies by dividing the keywords into clusters. Words present in the same clusters might represent the same concept/topic. Using the MCA methods for the conceptual structure map, two clusters were found [Figure 5]. The red-colored cluster seems to match clinical studies and the blue cluster corresponds to the animal studies and experimental studies.

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Figure 5:

Conceptual structure obtained from (a) PubMed and (b) Scopus.

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DISCUSSION

Bibliometric analysis is a good way at looking at global trends of the research within a topic, field, and across countries. It gives a wider outlook on the topic of interest. There are various publications on bibliometric analysis pertaining to spine topics,^[8,9] arthroscopy topics,^[10] and other orthopedic topics.^[11] To the best of our knowledge, this is the first bibliometric analysis on this topic and it provides a broad picture of the worldwide research in this upcoming orthobiologic field. PRP has emerged as a valuable therapeutic option for various musculoskeletal disorders due to the pool of growth factors it contains and its role is tissue healing.^[4] Initial studies in orthopedics were focused on PRP role in tendinopathies and started in 2006.^[12] The clinical use of PRP for early OA of knee was first used by Sanchez et al. in 2008^[13] and Kon et al.^[14] came up with the first RCT of PRP use in OA knee. We analyzed the time frame from 1975 to 2020 and it can be clearly seen that the boom in publications has been in the past decade and is seeing a steady rise in the number of publications in both Scopus and PubMed.

A PubMed search resulted in a smaller number of documents in comparison to Scopus due to its narrow scope and coverage. PubMed mostly covers biomedical and life sciences literature, whereas Scopus covers wider range of scientific topics. However, PubMed database is a freely available database whereas Scopus is based on the subscription model.

PubMed also has a sophisticated keyword optimization approach whereas Scopus provides search analysis tools that can produce representative figures. The alternate sources of bibliometric information such as Web of Science and Google Scholar are also available. However, Scopus data are considered to be more inclusive and accurate.^[15] Citation-related parameters are also better available in Scopus and using both PubMed and Scopus the databases, optimal results can be acquired.

The top three journals in terms of number of documents published are Arthroscopy – Journal of Arthroscopic and Related Surgery, American Journal of Sports Medicine, Osteoarthritis, and Cartilage. The American Journal of Sports Medicine has the highest total citations of 2366 and highest H-index of 19 in this particular field. Top journals in the respective subcategories (animal studies, clinical studies, review articles, and RCTs) are tabulated in [Table 5]. It gives a list of journals to follow and consider for publishing respective research for upcoming research work.

The prolific authors in this field are Kon E, Filardo G, Cole BJ, and Sanchez.^[16] [Table 5] also provides the top 10 authors in respective subcategories.

Original article by Patel et al. in 2013^[6] which first established the superiority of PRP over placebo for early OA knee is the highest cited paper with 386 citations in this field. Top five cited papers are tabulated in [Table 6].

The geographic distribution of scientific research in a particular field is important to analyze as it can give a rough idea of the research capabilities and available technologies in the countries and respective institutions. Researchers wanting to start these procedures can look forward to collaboration and fellowships and help from these relevant countries or institutions. The USA and China followed by Italy and Spain are the leading countries in research in this field. Six of the top 10 universities are in the United States and Rush University Medical Center (United States) tops the list of top universities involved in the research [Table 7]. Universities in the USA and Europe appear to be the leaders in this field.

During the beginning of the decade, there was a lot of hype around PRP use in orthopedics and there were a lot more review articles than original research and there was a need for more and more clinical trials.^[17] Even after 10 years of research, original clinical research articles (15.31% and 22.15%) are less compared to review articles (34.6% and 28.3%) in both PubMed and Scopus, respectively. The absence of adequate well-designed studies in this field is well recognized and hence evidence is equivocal and PRP is yet to find its mention in various international guidelines.^[18] Clinical research with well-designed studies is still the need of hour to establish the role of PRP in early OA knee.

CONCLUSION

The present study is the first bibliometric evaluation on the worldwide research productivity in the field of PRP and OA knee. There has been a steady increase in publication in this field and there are many journals which are publishing articles related to this relatively new field in orthopedics. There is a need for more clinical trials in this field.