Introduction

The number of times an article is cited represents a useful method to measure, together with other parameters, its academic influence. However, the academic influence of an article is not equally related to the quality of the article itself. The publication of the first orthopaedic-specific journals traced back to the end of the 1800s with Transactions of the American Orthopaedic Association (now evolved into the American and British versions of “The Journal of Bone and Joint Surgery” [1]).

Currently, there are 67 journals categorized under the topic heading of “Orthopaedics” in the Institute for Scientific Information (ISI) Web Science (Thomson Reuters, New York, New York, USA) ranging from general orthopaedics to orthopaedics sub-specialty areas. The quality and the amount of publications available are remarkable and since nineteenth century are more and more increasing. Such amount of publications comprises articles with both more and less academic impacts. In the past years, many authors had researched the most frequently cited articles under the topic of surgical and medical specialties [2–5]. In orthopaedics, few studies as those of Lefaivre et al. [6, 7] were conducted under the topic of general orthopaedics, whereas other authors specifically analysed the most frequently cited articles in orthopaedic sub-specialties [8–13]. The most frequently cited orthopaedic articles were also analysed by country of origin [14].

Therefore, this study aims to collect, categorize and analyse the 50 most frequently cited Italian articles in the orthopaedic literature. The above-mentioned article does not consider the quality of the analysed articles, whereas it aims to determine the reasons why such articles resulted within the most frequently cited ones.

Furthermore, this study also aims to identify the influence of the articles and the Italian authors in order to help possible future research and study in the international scientific literature.

Materials and methods

Since 1945, the Institute for Science Information has been collecting and categorizing citation and information regarding the academic impact of the published articles and scientific researches. Such information has been electronically available since 1979 using the citation system “Science Citation Index Expanded”, in Web of Science [15].

Using the Science Citation Index Expanded database through the ISI Web of Knowledge, in August 2014, we performed a comprehensive search in order to classify the 50 most frequently cited articles in the orthopaedic literature during the last 30 years. We first selected the articles ranging from year 1983 to 2013 within the Journal Citation Report Science Edition, and then, we searched for citations to articles published in the subject category “Orthopaedics”. After, we filtered by country to exclude articles not originating from Italy, with publications in English. The 200 most frequently cited Italian articles identified were reviewed to exclude articles without a primary address or a reprint address in Italy. Hence, the 50 most frequently cited Italian articles among articles, review articles or reports were identified. The data collected for each article included the article title, journal type, name of author/s, country of origin, year of publication, article type, article sub-type (original study, review article, opinion, case report) and the orthopaedic field. In addition, we determined the citation density that is the total number of citation/years since publication and the impact factor of the publication journals. These 50 articles were published in 12 of the 67 journals categorized under the topic heading of “Orthopaedics” in the ISI Web Science. A correlation analysis (Pearson) of the impact factor of the journal of publication and the number of citations was performed; in addition, we correlated the impact factor and the citation density of the top 50 articles. A value of p < 0.05 was considered to be statistically significant.

Results

A total of 193,826 articles were published in orthopaedic journals between 1988 and 2013, but only 3,803 of those articles were originated in Italy. All the articles of our list of the 50 most frequently cited Italian articles in the orthopaedic literature were published in English. The majority of those articles was published between 2000 and 2013 (n = 27), no publications between 2012 and 2013 were included in our list top 50 articles, and 2005 resulted the year of most frequently cited articles (n = 7). The number of citations for the 50 most frequently cited Italian articles ranged between 423 of the first article (mean citation/years 21.15) and 83 of the fiftieth (mean citation/years 16.60). The article title, author/s, year of publication, journal title where the article was published, number of citations and citation density/year are listed in Table 1. The articles of this list were published in 12 of the 67 journals categorized under the topic heading of “Orthopaedics” in the ISI Web Science, including three general orthopaedics journals and nine sub-specialty journals, as shown in Table 2.

Table 1 List of top 50 cited Italian orthopaedic articles
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Table 2 Number of articles on top 50 list by source journal
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The total number of publications/journal, the impact factor of 2013 and the impact factor of the last 5 years are shown in Table 3. With regard to the number of the article sub-type, 43 were original studies followed by 6 review articles and 1 report. The effect of the impact factor of the journal on the ranking was evaluated using a correlation analysis; however, there was no correlation between the impact factor of 2013 (r = −0.101; p = 0.321) or the impact factor of the last 5 years (r = 0.088; p = 0.279). A weak correlation was found between the year of publication and the number of citations (r = 0.220; p = 1.569).

Table 3 Number of articles on top 50 list by source journal
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Discussion

The importance and the influence of an article in the medical literature are also related to the number of citations obtained by the article itself. In fact, the number of citations indicates the number of times the article was read and made reference for future publications. The number of citations depends not only on the type of the article topic but also from the effect it has on the authors who read the article and make reference to the article for their future publications. However, the number of citations and the impact factor on the journal in which the article is published are not always an indication of the quality of the article itself. Indeed, both the names of the authors and the journals where the article is published may influence the number of citation significantly. Studies, as our study on the most frequently cited Italian articles in the orthopaedics field, were already made during the years by other authors in various specialties [1–4] and in the orthopaedics field, in different countries [13]. In Italy, thanks to the ancient tradition and the great number of authors and researchers, the research in the orthopaedics field has a significant role within the international scientific community (“Capozzo A, Catani F, Della Croce U, Leardini A (1995) Position and orientation in-space of bones during movement - anatomical frame definition and determination. Clinical biomechanics 10:171–178. doi:10.1016/0268-0033(95)91394-T” is the first Italian article within the most cited and is 86 out of 182,891 English articles from all over the world, whereas “Aglietti P, Buzzi R, Zaccherotti G, DeBiase P (1994) Patellar tendon versus doubled semitendinosus and gracilis tendons for anterior cruciate ligament reconstruction. American journal of sports medicine 22: 211–218. doi:10.1177/036354659402200210” is the second Italian articles and is ranked 203rd in the list). The results we obtained show a remarkable heterogeneity of the topics in the 50 most frequently cited articles in the Italian literature (nine orthopaedics sub-specialties), but 29 (58 %) of those articles can be enclosed in two sub-specialties: sport medicine/arthroscopy and biomechanics (see Table 4). These data, from our perspective, indicate the impact of such topics on the international literature encouraging the Italian researchers who are willing to increase the possibility of being cited to examine such topics in depth, but also these data reveal the importance of the contribution for the development of such academic disciplines given by the Italian orthopaedic scientific community during the last 30 years. Differently from other similar studies regarding general orthopaedics [6] or orthopaedics sub-specialties [7–12], our study does not show that the presence of a score or a classification within an article increases the number of citations of the article itself (the first and the only article containing a classification is the eighth within the 50 most cited articles: Boriani S, Weinstein JN, Biagini R. (1997) Spine update-primary bone tumours of the spine-terminology and surgical staging. Spine 22:1036–1044 doi:10.1097/00007632-199705010-00020). In accordance with Urrutia et al. [14], the study performed on the Italian orthopaedics literature did not show evidence of correlation between the impact factor of 2013 (r = −0.101; p = 0.321) and the impact factor of the last 5 years (r = 0.088; p = 0.279) and the number of citations. It is obvious that drawing up the list of the articles and defining the importance based on the number of citations have some limitations. As according to Lefaivre et al. [7] and Stern et al. [16], this type of citation analysis does not account for self-citation, citations in textbooks and lectures, and an author’s or authors’ potential preference to cite articles in the journal in which they seek to publish their work [7, 16]. Secondly, this study is limited by the categorization of journals in Web of Science. By design, only articles in the 67 journals categorized as “Orthopaedics” journals were considered. Although this represents a long and complete list of orthopaedic-specific journals, articles in the topic area of orthopaedic surgery published in general medical and basic science literature were not considered here in order to leave out work that has been influential in the specialty [16]. There is a clear time effect in citation analysis, with the most recent articles being at a disadvantage [17], but only a weak correlation was found (r = 0.220) between the year of publication and the number of citations with statistic relevance (p = 1.52). Finally, Kuhnian philosophy [18] would tell us that in a scientific community, there is a tendency for adherence to a paradigm. In this context, that would mean that there is “snowball effect” to citations, as other authors are more likely to cite it because of previous citations, rather than for its content or quality. Nonetheless, we should understand the characteristics that make articles citable by other authors in order to help researchers and universities in Italy to promote quality research in the fields that could become more influential for the international scientific community.

Table 4 Number of articles by field
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