- Review article
- Open Access
The most influential papers in unicompartmental knee arthroplasty
Knee Surgery & Related Research volume 32, Article number: 54 (2020)
Unicompartmental knee arthroplasty (UKA) is a treatment option for anteromedial osteoarthritis of the knee. The number of UKA has been increasing constantly worldwide in recent decades. The aim of this study was to determine the most frequently cited scientific articles addressing this subject and to establish a ranking of the 50 most influential papers.
The 50 most cited articles related to UKA were searched in Web of Science® (Clarivate Analytics, Penn., USA) by the use of defined search terms. All types of scientific papers with reference to this topic were ranked according to the absolute number of citations and analyzed for the following characteristics: journal title, year of publication, number of citations, citation density, geographic origin, article type, and level of evidence.
The 50 most cited articles had up to 453 citations. Most papers were published in the Journal of Bone and Joint Surgery (British volume). More than half of the articles were published in the 2000s and 2010s (n = 30). Ten countries contributed to the top 50 list, with most contributions from the UK (n = 17). Most articles could be attributed to the category of Clinical Science (n = 33), and most reported level IV studies.
Most of the frequently cited articles in UKA are clinical studies that have a low level of evidence. Few basic scientific studies could be identified, which suggests that most product development is done by commercial companies.
Unicompartmental knee arthroplasty (UKA) dates back to the 1950s, following the introduction of the MacIntosh and McKeever hemiarthroplasty . Since then, patient management, implant design, and surgical techniques, such as patient-specific instrumentation, have advanced [1, 2]. Nowadays, UKA is considered a less-invasive treatment option for anteromedial osteoarthritis than total knee (TKA) arthroplasty [3,4,5]. As a result, the number of UKA has been increasing constantly worldwide in recent decades [6,7,8]. Due to the clinical relevance of UKA, numerous scientific papers related to this topic were published, that is, more than 2000 articles.
A citation is a reference or a quotation from previous scientific work that has been published in books or scientific journals . The number of citations of published scientific articles is considered a parameter of its influence and impact in the scientific community. The impact factor of a journal is a widely accepted as a parameter of scientific quality and importance. It is calculated by the number of citations .
Analyses of citations in a specific scientific field allow us to give an overview of the most influential articles and offer physicians, researchers, and residents insight on the relevant current literature. Such studies have been done in different medical disciplines such as orthopedic surgery or general surgery; in a variety of orthopedic subspecialties including arthroplasty, arthroscopy, or hand surgery; and for conditions such as osteoporosis or anterior cruciate ligament rupture [10,11,12,13,14,15,16,17,18,19,20,21].
The aim of this study was to determine the most cited scientific articles related to UKA and to establish a ranking of the most influential papers by the use of the Web of Science® database.
Material and methods
In March 2020, Web of Science® (Clarivate Analytics, Penn., USA) was searched for the following search terms “Unicompartmental Knee Arthroplasty,” “Unicondylar Knee Arthroplasty,” “Unicompartmental Knee Replacement,” “Knee Arthroplasty,” “Knee Replacement,” “Implant,” and “Prosthesis.”
The search output was documented after completion of the search. All scientific articles related to UKA that could be identified were included and ranked according to the absolute number of citations (times cited in the Web of Science core collection). If the absolute number of citations was the same in two or more papers, the publication that had the higher citation density (see below) was ranked higher. The fifty most cited articles were chosen and represent the list of the most influential papers in UKA. The literature search and subsequent data analysis were done by a board-certified orthopedic surgeon.
The fifty most cited articles were studied in detail for the following characteristics: article title, journal title, year of publication, and origin of the corresponding author. Each publication was assigned to a single country of origin. This decision was based on the corresponding author’s address, as the corresponding author is in charge of the article and the guarantor of the data .
A citation density (the number of citations per year since publication) was calculated to show the relative impact of the included articles .
The included articles were allocated to different scientific categories as follows: “Clinical Science,” “Basic Science,” “Registry & Database,” and “Review.”
The level of evidence was assessed in all articles that were attributed to the Clinical Science category. This assessment was done according to the guidelines for clinical articles by the Oxford Centre for Evidence-Based Medicine 2016 Levels of Evidence .
The absolute number of citations for the fifty most cited articles on UKA range from 110 to 453 times. The fifty articles were cited, in total, 8436 times. The mean number of citations of an included paper was 169 times (± 69). The top ten papers reached at least 219 citations since publication.
The absolute numbers of citations for the fifty most influential articles on UKA are shown in Table 1, and the top ten papers, according to their relative number of citations (highest citation density), are presented in Table 2.
Thirty-three articles were allocated to the “Clinical Science” category, which was the most frequently noted category. Figure 1 presents the distribution according to the different categories.Within the category “Clinical Science,” the level of evidence was analyzed. Eighteen studies of this category were categorized as level IV studies. The distribution of the level of evidence is shown in Fig. 2.
The Journal of Bone and Joint Surgery (British volume) has published most papers of the list (n = 16). The Journal of Bone and Joint Surgery (American volume), Clinical Orthopaedics and Related Research, Acta Orthopaedica (Scandinavica), Journal of Arthroplasty, Lancet, and Knee were other journals that contributed to the list (Fig. 3).
Research institutions from the UK had the highest number of contributions (n = 17). Nine further countries contributed to the top 50 list: the USA with 16; Sweden with six; France with four; Finland with two; and Australia, Austria, Canada, India, and Norway with one each. Thirty-one publications were from Europe and 17 from North America.
The publication years of these articles span 1981 to 2014. Figure 4 shows the decade in which the research was published. Most articles were published in the 2000s (n = 23), followed by the 1990s (n = 13), and then the 1980s and 2010s with seven publications per decade.
UKA is considered an alternative treatment option for anteromedial osteoarthritis to TKA. Because of the growing scientific interest in the field of UKA, we tried to identify the most influential articles related to UKA as guidance for clinical practice and future research. Publications on UKA were cited up to 453 times since publication, with the top ten articles in this field being cited at least 219 times. The citation number of articles in UKA is lower than in other fields of orthopedics, such as total hip and knee arthroplasty, cartilage surgery, and anterior cruciate ligament injury [13, 16, 20, 21]. However, compared to articles on hand surgery or pediatric orthopedics, articles on UKA are well cited [15, 18]. This indicates that the field of UKA is a highly driven industry such as the field of arthroplasty on the whole [24, 25].More than two-thirds of the articles were attributed to the category “Clinical Science.” Most of these were level IV studies, which indicates a low level of evidence in the field of UKA. This points to a need for clinical studies in UKA with better study design so as to gain more evidence in the future. Only three articles were level I studies. Two of these were prospective randomized controlled trials comparing UKA and TKA in the treatment of osteoarthritis of the knee.
The second most frequent category was “Registry and Database,” with ten articles. This indicates the great interest in implant performance and survival. Only six papers were in the category “Basic Science.” Product developments in the field of UKA are mostly done by commercial companies. These products are then used in clinical practice and studied clinically. Interestingly, the most highly cited contributions in the field of UKA were from the UK (n = 17). This is in contrast to most bibliometric analyses done so far, in which the USA contributed most of the scientific work [10,11,12,13,14,15,16,17,18,19,20,21]. Furthermore, in the field of UKA, a high number of contributions are from European countries, especially Scandinavian ones. This is also confirmed by the publishing journals. A large proportion of the articles was published in the Journal of Bone and Joint Surgery (British volume). Another seven articles were published in European journals. This finding is also in contrast to other bibliometric analyses in orthopedic surgery so far [10,11,12,13,14,15,16,17,18,19,20,21]. Interestingly, most articles have been published since 2000. This indicates an increasing trend in UKA in the last recent decades.
In general, bibliometrics has its limitations. The identification of the fifty most cited papers still remains a selection, even when using predefined search criteria. In this study, the absolute number of citations was considered an objective parameter. Among the scientific community, the impact factor is an accepted parameter of an article’s influence. The impact factor is directly influenced by the number of citations. However, the citation numbers of articles can be manipulated by various factors such as self-citations (in small numbers) and therefore might not necessarily represent the objective value of scientific work .
The literature search was performed in the Web of Science®. Textbooks, doctoral theses, presentations, and new media are not included in this database. Therefore, citations of articles of such sources might have been missed.
Another limiting factor might be the cross-sectional study design based on total citation numbers. As a result, more recent influential papers might not have been identified and were not considered eligible for the list.
This study provides a list of the fifty most influential articles on UKA, which will help physicians and scientists to obtain an overview on past and current trends in the field of UKA. Most articles could be attributed to the category Clinical Science and provided a low level of evidence. This provides a basis for both further discussion and highlights the need for future research.
Availability of data and materials
The datasets developed during and/or analyzed during the current study are available from the corresponding author on reasonable request.
Johal S, Nakano N, Baxter M, Hujazi I, Pandit H, Khanduja V (2018) Unicompartmental knee arthroplasty: the past, current controversies, and future perspectives. J Knee Surg 31:992–998
Vince KG, Cyran LT (2004) Unicompartmental knee arthroplasty: new indications, more complications? J Arthroplast 19:9–16
Jennings JM, Kleeman-Forsthuber LT, Bolognesi MP (2019) Medial unicompartmental arthroplasty of the knee. J Am Acad Orthop Surg 27:166–176
Murray DW, Parkinson RW (2018) Usage of unicompartmental knee arthroplasty. Bone Joint J 100-B:432–435
Christ AB, Pearle AD, Mayman DJ, Haas SB (2018) Robotic-assisted unicompartmental knee arthroplasty: state-of-the art and review of the literature. J Arthroplast 33:1994–2001
Riddle DL, Jiranek WA, McGlynn FJ (2008) Yearly incidence of unicompartmental knee arthroplasty in the United States. J Arthroplast. 23:408–412
Kahlenberg CA, Richardson SS, Gruskay JA, Cross MB (2020) Trends in utilization of total and unicompartmental knee arthroplasty in the United States. J Knee Surg. https://doi.org/10.1055/s-0040-1702189
Hansen EN, Ong KL, Lau E, Kurtz SM, Lonner JH (2018) Unicondylar knee arthroplasty in the U.S. patient population: prevalence and epidemiology. Am J Orthop (Belle Mead NJ) 47. https://doi.org/10.12788/ajo.2018.0113
Lee KP, Schotland M, Bacchetti P, Bero LA (2002) Association of journal quality indicators with methodological quality of clinical research articles. JAMA 287:2805–2808
Kelly JC, Glynn RW, O'Briain DE, Felle P, McCabe JP (2010) The 100 classic papers of orthopaedic surgery: a bibliometric analysis. J Bone Joint Surg Br 92:1338–1343
Lefaivre KA, Shadgan B, O'Brien PJ (2011) 100 most cited articles in orthopaedic surgery. Clin Orthop Relat Res 469:1487–1497
Paladugu R, Schein M, Gardezi S, Wise L (2002) One hundred citation classics in general surgical journals. World J Surg 26:1099–1105
Holzer LA, Holzer G (2014) The 50 highest cited papers in hip and knee arthroplasty. J Arthroplast 289:453–457
Cassar Gheiti AJ, Downey RE, Byrne DP, Molony DC, Mulhall KJ (2012) The 25 most cited articles in arthroscopic orthopaedic surgery. Arthroscopy 28:548–564
To P, Atkinson CT, Lee DH, Pappas ND (2013) The most cited articles in hand surgery over the past 20-plus years: a modern-day reading list. J Hand Surg 38A:983–987
Arshi A, Siesener NJ, McAllister DR, Williams R 3rd, Sherman SL, Jones KJ (2016) The 50 most cited articles in orthopedic cartilage surgery. Cartilage 7:238–247
Namdari S, Baldwin K, Kovatch K, Huffman GR, Glaser D (2012) Fifty most cited articles in orthopaedic shoulder surgery. J Shoulder Elb Surg 21:1796–1802
Kavanagh RG, Kelly JC, Kelly PM, Moore DP (2013) The 100 classic papers of pediatric orthopaedic surgery: a bibliometric analysis. J Bone Joint Surg Am 95:e134
Holzer LA, Leithner A, Holzer G (2015) The most cited papers in osteoporosis and related research. J Osteoporos 2015:638934
Vielgut I, Dauwe J, Leithner A, Holzer LA (2017) The fifty highest cited papers in anterior cruciate ligament injury. Int Orthop 41:1405–1412
Ennis HE, Bondar K, McCormick J, Chen CJ, Donnally CJ 3rd, Kaplan L (2020) The 50 most cited articles in the indications, risk factors, techniques, and outcomes of ACL revision surgery. J Knee Surg. https://doi.org/10.1055/s-0040-1702182
Rennie D, Flanagin A, Yank V (2002) The contributions of authors. JAMA 284:89–91
OCEBM Levels of Evidence Working Group. “The Oxford levels of evidence 2”. Oxford Centre for Evidence-Based Medicine. https://www.cebm.net/2016/05/ocebm-levels-of-evidence. Accessed 28 Mar 2020.
Holzer LA, Holzer G (2013) Analysis of scientific articles published in two general orthopaedic journals. Acta Ortop Bras 21:281–284
Boddapati V, Sachdev R, Fu MC, Camp CL, Marx RG, Dines JS (2018) Increasing industry support is associated with higher research productivity in orthopaedic surgery. J Bone Joint Surg Am 100:e36
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Holzer, L.A., Holzer, G. The most influential papers in unicompartmental knee arthroplasty. Knee Surg & Relat Res 32, 54 (2020). https://doi.org/10.1186/s43019-020-00072-1
- Unicompartmental knee arthroplasty
- Unicondylar knee arthroplasty
- Bibliometric study
- Citation analysis