1. Global publication trends
Number of global publications
A total of 8631 publications eventually were collected after applying the search criteria. Over the past decade, the number of publications has steadily increased year by year, from 483 (2010) to 1083 (2019). In addition, most of the researches were published in 2019 (1083, 12.5%) (Figure 1A).
Contributions of countries and regions
Moreover, a total of 86 countries and regions have published related articles/review, and the countries which had made the greatest contributions in TKA research were presented in Figure 1B and C. Among them, the United States contributed to the most publications (2835, 32.8%), followed by China (835, 9.7%), Japan (657, 7.6%), and the United Kingdom (652, 7.6%).
Global trends of publications
In order to predict the future, the time curve of the all-year publication numbers was created by using the logistic regression model, and the model fitting curves of the growth trend was shown in Figure 1D. Furthermore, with the help of this time curve, it’s estimated that the number of the publications in this domain would grow by nearly 3.5 times from 483 in 2010 to approximately 1700 by 2030.
2. Quality of the publications of each country/region
Total citation frequency
The USA had the highest number of total citations (42,461) among all the included publications, while the UK ranked the second (9487), then followed by Canada (8541), China (7199), and Germany (5715) (Figure 2A).
Average citation frequency
Publications from Denmark had the most average number of citations (22.39), then followed by Canada (20.73), Belgium (18.02), Netherlands (16.91), and the UK (15.18) (Figure 2B).
As shown in Figure 2C, the USA outranked other countries and regions with the most top H-index of 74, followed by Canada (43), the UK (43), China (35), and Germany (33).
3. Analysis of global publication
JOURNAL OF ARTHROPLASTY published 1486 articles/reviews, outranking other journals with the most publications. KNEE SURGERY SPORTS TRAUMATOLOGY ARTHROSCOPY ranked the second, with 762 publications. Moreover, there were 494 articles/reviews in KNEE, 285 in JOURNAL OF KNEE SURGERY, and 258 in INTERNATIONAL ORTHOPAEDICS on the TKA field. The top 20 journals with most publications were presented in Figure 3A.
The top 20 research orientations relevant to TKA were shown in Figure B. The most prevalent areas of research were orthopedics (6013 papers), surgery (2675 papers), sport science (1586 papers), engineering (432 papers), and general internal medicine (418 papers) respectively.
The top 20 authors with the greatest number of related publications were shown in Figure 3C, who have published a total of 1151 articles/reviews during the last decade, accounting for 13.3% of all literature in this field. Mont MA from the USA outranked other authors with a publications of 169 papers, followed by Matsumoto T from Japan with 64 papers, and Yeo SJ from Singapore with 63 papers. It’s noteworthy that we included all the authors for analysis in this study, regardless of the authors’ relative contribution towards one single research.
Hospital special surgery had the greatest number of publications with 234 papers, followed by Mayo clinic (210 papers), and then University of California system (201 papers). Figure 3D presented the top 20 institutions with most publications.
4. Bibliographic coupling analysis
As a well-established method of citation analysis, bibliographic coupling helps create a similarity relationship between documents on the basis of the number of references they share. When two works refer to a common third one in their bibliographies, bibliographic coupling occurs as an indication of sharing a related subject matter for these two works. The VOS viewer was used to analyze the journal names of all publications.
As illustrated in Figure 4A, a total of 172 journals appeared (the minimum number of publications of each journal was over five) in terms of total link strength (TLS). The top five journals with the largest TLS were shown as follows: JOURNAL OF ARTHROPLASTY (TLS=1158621 times), KNEE SURGERY SPORTS TRAUMATOLOGY ARTHROSCOPY (TLS=777852 times), KNEE (TLS=458865 times), CLINICAL ORTHOPAEDICS AND RELATED RESEARCH (TLS=281285 times), INTERNATIONAL ORTHOPAEDICS (TLS=271771 times).
Papers originating from 750 institutions were analyzed via VOS viewer, and the minimum number of publications from each institution was over five in the bibliometric map (Figure 4B). The top five institutions with the greatest TLS were as follows: Mayo clinic (TLS=287724 times), Hospital for Special Surgery (TLS=242212 times), Singapore general hospital (TLS=181272 times), Seoul national university (TLS=145571 times), and University Colorado (TLS=139958 times).
Country and regions
There were 57 country and regions included (the minimum number of publications from each country or region was over five) and all the publications were analyzed by VOS viewer (Figure 4C). The top five country and regions with largest TLS were presented as follows: the USA (TLS=1933073 times), Germany (TLS=680506 times), Japan (TLS=632174 times), South Korea (TLS=631428 times), and China (TLS=609660 times).
5. Coauthorship analysis
Coauthorship analysis illustrates the relationship among items based on the number of the coauthored documents, which was a powerful tool to assess collaboration trends and to identify leading scientists, countries, and organizations.
As presented in Figure 5A, a total of 1584 authors with a minimum limitation of more than 5 publications were identified and analyzed via VOS viewer. The top five authors with greatest TLS were shown as follows: Mont MA (TLS=768 times), Matsumoto T (TLS=414 times), Kuroda R (TLS=400 times), Kurosaka M (TLS=340 times), and Ishida K (TLS=325 times).
Countries and regions
A total of 56 countries and regions with a minimum limitation of more than 5 publications were identified and analyzed by using VOS viewer (Figure 5B). The top five country and regions with largest TLS were presented as follows: the USA (TLS=677 times), the UK (TLS=318 times), Germany (TLS=258 times), Canada (TLS=219 times), and Australia (TLS=204 times).
As shown in Figure 5C, there were 712 institutions finally included with a minimum limitation of more than 5 publications, whose publications were analyzed by VOS viewer. Moreover, Hospital for Special Surgery (TLS=224 times), Cleveland clinic (TLS=191 times), University Colorado (TLS=154 times), Mayo clinic (TLS=142 times), and University Tennessee (TLS=128 times) were the top five institutions with greatest TLS.
6. Cocitation analysis
Cocitation analysis establishes the relationship of items on the basis of how many times they are cited together, and is demonstrated as a way to help identify key literature for cross-disciplinary ideas.
A total of 2141 publications were included (the minimum number of citations for one reference was over 20 times) and analyzed via VOS viewer (Figure 5D). The top five publications with largest TLS were presented as follows: Insall et.al (TSL=13413 times), Kurtz et.al (TSL=8451 times), Ewald et.al (TSL=7568 times), Bourne et.al (TSL=6666 times), and Berger et.al (TSL=6571 times).
The journal was included if the minimum number of citations from one source was over 20 times. In total, there were 902 journals which met the aforementioned criteria (Figure 5E). The top five journals with greatest TLS were illustrated as follows: CLINICAL ORTHOPAEDICS AND RELATED RESEARCH (TLS=941132 times), JOURNAL OF ARTHROPLASTY (TLS=900527 times), JOURNAL OF BONE AND JOINT SURGERY AMERICAN VOLUME (TLS=643757 times), JOURNAL OF BONE AND JOINT SURGERY BRITISH VOLUME (TLS=398451 times), and KNEE SURGERY SPORTS TRAUMATOLOGY ARTHROSCOPY (TLS=310785 times).
7. Co-occurrence analysis
Co-occurrence analysis illustrates the relationship of items based on the number of publications where they occur together. Not only the popular areas and research directions could be identified through co-occurrence analysis, but also it turns out to be an important indicator to monitor developments in scientific areas and other disciplines. The keywords, which were used over five times among included publications, were identified and analyzed via VOS viewer. As presented in Figure 6A, the 2225 included keywords could be divided into approximately 5 clusters: “alignment study”, “revision TKA study”, “complication study”, “rehabilitation study”, and “perioperative management study” (Figure 6A). The most prominent topics about TKA research were shown as follows. In the cluster of “alignment study”, the main keywords were alignment, kinematics, flexion, and system. As for the “revision TKA study” cluster, the primary keywords were follow-up, prosthesis, revision, and fixation. In the “complication study” cluster, the most used keywords were surgery, meta-analysis, management, and complications. As for the “rehabilitation study” cluster, the prominent keywords were osteoarthritis, pain, rehabilitation, and quadriceps strength. In the cluster of “perioperative management study”, the frequently used keywords were efficacy, post-operative pain, double-blind, and femoral nerve block.
In Figure 6B, different colors were applied by VOS viewer for each keyword, based on the mean times they appeared in the all included publications. The color blue indicated the keywords appeared earlier, whereas the color red stood for the later occurrence. As illustrated in Figure 6B, a trend of balanced development existed in all the five clusters respectively during the past decade. By comparison, more studies focused on the cluster of "revision TKA" after 2014. However, recent trends indicated that the other four clusters were also undergoing different degrees of changes on the research hotspot, which meant a diversified developing trend.