Potential Sex Bias Exists in Orthopaedic Basic Science and Translational Research

Background: Potential sex bias has been shown in general surgery basic science and translational research, with unequal representation of male and female specimens. Because basic science research forms the foundation for clinical studies on which patient care is based, it is important that this research equally consider both sexes. The purpose of this study was to determine if potential sex bias exists in the basic science and translational orthopaedic literature. Methods: A systematic review was conducted of all articles published in 2014 in The Journal of Bone & Joint Surgery, Clinical Orthopaedics and Related Research, The Bone & Joint Journal, and the Journal of Orthopaedic Research (JOR). All original research articles utilizing animals, cells, or cadavers were included. The data abstracted included study type, sex of specimen studied, and presence of sex-based reporting of data. A second review was performed of all basic science articles published in JOR in 1994, 2004, and 2014 to compare sex bias trends across 3 decades. Distributions of variables were compared using the Fisher exact test, with significance defined as p < 0.05. Results: Of 1,693 articles reviewed, 250 (15%) were included: 122 animal-based studies (49%), 71 cell-based studies (28%), and 57 human cadaver-based studies (23%). Overall, authors in 88 studies (35%) did not report the sex of animals, cells, or cadavers used. Of 162 studies in which the authors did report sex, 69 (43%) utilized male only, 40 (25%) utilized female only, and 53 (33%) utilized both sexes. Of those studies that used both sexes, authors in only 7 studies (13%) reported sex-based results. A subanalysis of JOR articles across 3 decades revealed a significant increase in studies specifying sex (p = 0.01) from 2004 to 2014. Conclusions: Potential sex bias exists in orthopaedic surgery basic science and translational research, with an over-representation of male specimens.