Fifty top-cited fracture articles from China: a systematic review and bibliometric analysis

Background With more than 50,000 orthopaedic surgeons, China is having an increasing impact on fracture surgery research. However, the most influential Chinese articles on fracture surgery have not been determined. This study aimed to characterise the most-cited articles on fracture surgery by Chinese authors to provide insight into the fracture research in China. Methods The Web of Science was used to search for citations of fracture surgery articles that originated in China. The 50 most-cited articles were identified. The title, number of citations, year of publication, journal, article type, level of evidence, city, institution, and authors were recorded and evaluated. Results The 50 top-cited papers were published between 1984 and 2012. The most prolific decade began in the year 2000. These articles received 28 to 209 citations (mean 52), were written in English, and published in 12 journals. Injury was the most popular journal, with the largest number of articles (11) on the top 50 list. The region with the largest number of published articles was Hong Kong (20), followed by Kaohsiung (8), Shanghai (8), and Taipei (7). Most were clinical studies (39), while the remaining studies were basic science articles (11). The hip was the most common topic in the clinical studies. The most popular level of evidence was IV. Conclusions This list of the top 50 publications identifies the most influential Chinese fracture surgery articles for the global community. This study presents insight into the historical contributions of Chinese researchers and the fracture surgery trends in China.


Background
The number of citations that a paper receives is a significant indicator of its influence and contribution to a certain field [1][2][3]. Citation analysis is an important measurement for assessing the academic significance of a paper [1][2][3]; it is a bibliometric method used to investigate the characteristics of a paper's citations. Many bibliometric studies have been conducted to investigate the top-cited papers in medical fields, such as diabetes, hypertension, osteoporosis, imaging, dentistry, cardiac surgery, and orthopaedics [4][5][6][7][8][9][10].
China is the most populous territory with over 1.3 billion people and is one of the most rapidly developing countries in the world [11]. Moreover, China has more than 50,000 orthopaedic surgeons [12]. The fracture research studies by these surgeons have resulted in great progress in recent years, gaining increasing attention from universities worldwide. China has an opportunity to become one of the leading forces in fracture surgery worldwide [13,14]. However, to our knowledge, influential fracture papers that have originated in China have not been analysed. Therefore, the present study aimed to analyse the 50 top-cited fracture papers from China and to assess their characteristics to provide insight into Chinese research on fracture surgery.

Methods
This study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement [15]. We adopted the designs of previous publications as models for the design of this study [4][5][6][7][8][9]. On October 15, 2015, a citation search was conducted using the Web of Science (Thomson Reuters, Philadelphia, Pennsylvania, USA). A total of 72 journals were under the "Orthopedics" category of the Journal Citation Reports (JCR) for the year 2014. All of these journals were included in the search for the top-cited papers in this study.
The inclusion criteria were as follows: (1) fracturerelated articles, (2) articles originating in China, and (3) those ranked as one of the top 50 papers according to the number of citations. Two authors independently conducted the literature search and data collection. Disagreements were resolved by discussion, and a third reviewer was consulted for the final decision if necessary. First, we entered the journal titles in the search window using the "OR" operator in the Web of Science database so that all articles from the 72 journals were identified. We then ranked the articles according to the number of citations. The search results were refined by selecting the filters "Peoples R China," "Hong Kong," "Taiwan," and "Macau." In addition, this study sought to include papers that orthopaedic trauma surgeons would find relevant to their practice. Thus, other articles on fractures, such as spine fracture, paediatric fracture, hand fracture distal to the wrist, stress fracture, infection not specifically related to fracture surgery, and arthroplasty, were excluded according to previous publications [16]. Each paper was reviewed, and papers without a first-author address from a Chinese region were excluded. Thereby, the inclusion of articles not originating in China but having one or more Chinese coauthors was avoided. The 50 top-cited Chinese papers on fracture surgery were finally collected. The title, number of citations, year of publication, journal source, article type, level of evidence, city, institution, and authors were analysed. The level of evidence for clinical studies was in accordance with the guidelines published by The Journal of Bone & Joint Surgery-American Volume [17].

Results
We initially identified 235,129 articles. The 50 mostcited articles from China were included in this study. Table 1 shows the 50 top-cited articles. The number of citations ranged from 209 to 28 (mean 52). The oldest paper, written in 1984, ranked 49th, while the most recent article, published in 2012, ranked 18th. The 2000s accounted for the most articles (24), followed by the 1990s (17), 2010s (5), and 1980s (4) (Fig. 1).
The 50 top-cited articles were published in English in 12 journals (Table 2). Injury (11)  Eleven studies were basic science articles, while 39 were clinical studies. The hip was the most discussed topic in the clinical studies, followed by the distal radius (Fig. 2). The most common article type among the clinical studies was case series ( Table 3). Most of the clinical studies had a level of evidence of IV (29) (Fig. 3).  The top 50 papers originated from mainland China (13), Hong Kong (20), and Taiwan (17). None of the articles originated from Macau (0). Eleven cities contributed to these 50 articles, led by Hong Kong (20) and followed by Kaohsiung (8), Shanghai (8), and Taipei (7) ( Table 4). Twenty-two institutions contributed to the top 50 articles. Eight institutions had at least two articles published. The Prince of Wales Hospital had the most published papers (11), followed by Queen Mary Hospital (6) and Chang Gung Memorial Hospital in Kaohsiung (5) ( Table 5). Multiple first-authors appeared more than once in the top 50 articles. The top first author was Leung KS (9), followed by Wang CJ (2), Leung F (2), and Lin J (2) ( Table 6).

Discussion
The top-cited articles represent the most influential articles in their respective fields [4][5][6][7][8][9]. Citation analysis helps to identify significant research studies, the important contributors, and their main characteristics [4-9, 16, 18]. In addition, understanding the historical context, developing processes, and future trends in a certain field can be helpful [4][5][6][7][8][9]18]. The number of publications regarding investigations of the most-cited articles in medical fields has been increasing [4][5][6][7][8][9]. Similarly, a paper that investigated the most-cited articles on fracture surgery was published in 2013 [16]. However, only one Chinese article was included in that study [16]. Therefore, the most-cited articles from Chinese authors in the field of fracture had not been investigated despite the increasing importance of Chinese research studies in the global community. To our knowledge, this is the first study to have identified the top-cited Chinese articles on fracture surgery.
The number of citations of the 50 top-cited publications ranged from 209 to 28. The reason that few Chinese articles have appeared on previous top article lists may be due to the smaller number of citations than those in the global community [16]. This result indicates that even though there has been a rapid increase in research output, Chinese authors should also work to improve the quality of their research studies [19]. However, this study also demonstrates that the 2000s was the most productive decade, indicating an increasing volume of important research studies from Chinese authors. It is reasonable to expect that China will contribute more influential papers in the future.
The 50 papers were all published in English, probably because English is the most common language used in fracture surgery articles [16]. Moreover, this may suggest a reason why fewer fracture articles from China were published in English journals, as Chinese authors may find it difficult to write their research studies in English.
The top 50 papers were published in 12 journals. The journal that included the largest number of papers was  Injury, indicating that high-level Chinese articles on fracture surgery are likely to be published in Injury. Therefore, this journal plays an important role in the sharing of Chinese knowledge in the field of fracture surgery. A previous study demonstrated that the impact factor of the journal was the most important indicator of the number of citations, and a large proportion of the most-cited papers were published in other high-impact journals [20]. However, this was not borne out by our study. The Journal of Bone & Joint Surgery-American Volume, which has the highest impact factor (5.28) on the journal list, published fewer articles than Injury. This result suggests that citations are not necessarily affected by the journal impact factor because various other factors contributed to the citations for certain journals [10,21].
Although mainland China has the highest number of patients and physicians among the Chinese regions, Hong Kong published the most papers on the top 50 list. This indicates that Hong Kong produces more high-quality papers than other Chinese regions. Similar findings have also been published previously [22]. Eleven cities were responsible for the top 50 papers. The ranking was led by Hong Kong, followed by Kaohsiung, Shanghai, and Taipei. These top four cities published nearly 90 % of the articles on the top 50 list. This finding confirms the important influence of these cities on fracture surgery in China. It also suggests that high-level Chinese research on fracture surgery is concentrated in several cities, which can be attributed to the large size of the orthopaedic communities in these cities and sufficient financial support [23,24].   On the top 50 list, clinical studies were more popular than basic science research, which is consistent with the situation in the global community [16]. One of the contributing factors may be that China's large population is advantageous to the recruitment of participants. The clinical articles focused on a variety of different topics. Hip fracture was the most discussed topic, which was consistent with the findings of a previous publication [16]. Most clinical articles had level IV evidence. This result indicates that the level of evidence do not necessarily influence the total number of citations. Moreover, some institutions and authors had good publication records in the field of fracture surgery; for example, The Prince of Wales Hospital and Leung KS were at the top of the list. Their output of high-level articles suggests their specific contributions to the field of fracture surgery and their great impact in China. This study has several limitations. First, high-impact articles were identified through a validated method, but influential Chinese papers with fewer citations might have been excluded. Second, we used categories to identify orthopaedic journals, which might not include all fracture articles. Influential Chinese articles on general medicine and basic research journals were not evaluated. Third, multiple factors influenced the number of citations. Self-citation and citations in textbooks and lectures could not be investigated in this study [10,25,26]. In addition, the authors tended to cite papers from the journals to which they submit their own research studies [27]. Fourth, this is a study with a cross-sectional design conducted at a single time point. The rankings of the list could change if the study were to be performed at a subsequent time point.

Conclusions
This study is the first bibliometric study of the mostcited Chinese papers on fracture surgery. The present study shows the most influential Chinese articles for global orthopaedic trauma surgeons and provides an overview of the impact of Chinese research studies on fracture surgery. This study provides historical insight into Chinese fracture research and the trends in the field of fracture surgery in China.