Authorship proliferation in the orthopaedic literature.

BACKGROUND: Authorship is the currency of the academic orthopaedic surgeon. There has been an unprecedented increase in the number of authors per publication in many biomedical fields. Possible reasons for this trend include increased complexity of research, "undeserved" authorship, and the "pressure to publish." We explored the change in authorship in two leading orthopaedic journals over a period of sixty years.
METHODS: We examined all original research articles and case reports published in The Journal of Bone and Joint Surgery (American and British Volumes) (JBJS-A and JBJS-B) in ten-year intervals from 1949 to 2009. For each article, we determined the number of authors, the geographic origin of the research, and the academic degrees of the authors; we also examined the changes that occurred in these categories.
RESULTS: The mean number of authors per original research article increased from 1.6 in 1949 to 5.1 in 2009. There has been a noticeable internationalization of the two journals, with a decreasing proportion of articles from North America and the United Kingdom and Ireland as a result of increased contributions from Europe and the Far East. Authors with advanced research degrees (PhD; MS; MD, PhD; and MD, MS) account for an increasing proportion of contributing authors; over 30% of authors had an advanced research degree in 2009.
CONCLUSIONS: Our findings suggest that the trend of authorship proliferation in biomedical research is also seen in the orthopaedic literature. The mean number of authors, the proportion of authors per research article with an advanced research degree, and variation in the geographic origin of articles has increased over the past sixty years.