The hundred most cited publications in orthopaedic hip research - a bibliometric analysis.

Background: The aim of this study was to identify the 100 most cited classics in the field of hip research analysing their qualities and characteristics.

Methods: Hip joint related articles were identified and the hundred most cited selected for subsequent analysis of citation count, current citation rate, citation density (citations/article age), authorship, geographic origin institution, and level of evidence (LOE).

Results: In a total of 121 journals, 1,311,851 articles were published between 1945 and 2013, of which 1,287 (0.1%) possessed 250 citations or more. Total citations per article for the 100 most-cited ranged from 290 to 3,144 citations.The most common areas of research were degenerative disease and arthroplasty, followed by hip preserving surgery for which the leading authors were William H. Harris and Reinhold Ganz respectively. All articles were published in 8 journals and originated from 9 countries. 10 institutes published 48/100 of the articles. There was a significant negative correlation between both citation rate, citation density and article age. Total citation count was highest for articles published in the decade of 1970. Although 5% (2,103 articles) of hip literature comprised randomised trials (RCTs), only 1 (1%) of the citation classics was an RCT.

Conclusions: The study provides intellectual milestones in hip research, reflecting on the qualities and characteristics of the research. Degenerative hip disease and arthroplasty research take up the greatest proportion of citations, followed by hip preserving research. LOE was low and there was only one RCT amongst the classics, emphasising that high LOE is not a prerequisite for a high citation count.