Design, Conduct, and Interpretation of Nonrandomized Orthopaedic Studies--A Practical Approach   |    
Principles of Designing a Cohort Study in Orthopaedics
Dianne M. Bryant, MSc, PhD1; Kevin Willits, MD, FRCSC2; Beate P. Hanson, MD, MPH3
1 Faculty of Health Sciences, The University of Western Ontario, Elborn College, Room 1438, 1201 Western Road, London, ON N6G 1H1, Canada. E-mail address: dianne.bryant@uwo.ca
2 Faculty of Medicine and Dentistry, Department of Surgery, The University of Western Ontario, 3M Centre, London, ON N6A 3K7, Canada
3 AO Foundation, Clinical Investigation and Documentation, Stettbachstrasse 6, 8600 Dübendorf, Switzerland
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Disclosure: The authors did not receive any outside funding or grants in support of their research for or preparation of this work. Neither they nor a member of their immediate families received payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity.

The Journal of Bone and Joint Surgery, Inc.
J Bone Joint Surg Am, 2009 May 01;91(Supplement 3):10-14. doi: 10.2106/JBJS.H.01597
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A well-designed and executed prospective cohort study can provide high-quality evidence in the evaluation of the effectiveness of surgical interventions. In designing a cohort study to evaluate orthopaedic interventions, it is important to recognize the limitations of the design as well as the methodological features that can be incorporated to strengthen the validity of the conclusions. In this article, we discuss the importance of the appropriate selection of participants for a control group, the management of confounders, the selection of outcomes with established measurement properties (reliability, validity, and sensitivity to change), the blinded assessment of outcomes, and the impact of nonparticipants and patients lost to follow-up.

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    These activities have been planned and implemented in accordance with the Essential Areas and policies of the Accreditation Council for Continuing Medical Education (ACCME) through the joint sponsorship of the American Academy of Orthopaedic Surgeons and The Journal of Bone and Joint Surgery, Inc. The American Academy of Orthopaedic Surgeons is accredited by the ACCME to provide continuing medical education for physicians.
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