Proposed Definitions and Criteria for Reporting Time Frame, Outcome, and Complications For Clinical Orthopedic Studies in Veterinary Medicine James L. Cook 1 , DVM, PhD, Diplomate ACVS, Richard Evans 2 , PhD, Michael G. Conzemius 3 , DVM, PhD, Diplomate ACVS, B. Duncan X. Lascelles 4 , BVSc, PhD, Diplomate ECVS, Diplomate ACVS, C. Wayne McIlwraith 5 , BVSc, PhD, Diplomate ACVS, Antonio Pozzi 6 , DMV, MS, Diplomate ACVS, Peter Clegg 7 , MA, VetMB, PhD, Diplomate ECVS, MRCVS, John Innes 7 , BVSc, PhD, DSAS (Orth), MRCVS, Kurt Schulz 8 , DVM, Diplomate ACVS, John Houlton 9 , MA, VetMB, DVR, DSAO, MRCVS, Diplomate ECVS, Lisa Fortier 10 , DVM, PhD, Diplomate ACVS, Alan R. Cross 11 , DVM, Diplomate ACVS, Kei Hayashi 12 , DVM, PhD, Diplomate ACVS, Amy Kapatkin 12 , DVM, MS, Diplomate ACVS, Dorothy Cimino Brown 13 , DVM, MSCE, Diplomate ACVS, and Allison Stewart 2 , DVM, MS, Diplomate ACVS 1 Comparative Orthopaedic Laboratory, University of Missouri, Columbia, MO, 2 College of Veterinary Medicine, University of Illinois, Urbana, IL, 3 College of Veterinary Medicine, University of Minnesota, St. Paul, MN, 4 Comparative Pain Research Laboratory, North Carolina State University, Raleigh, NC, 5 Orthopaedic Research Center, Colorado State University, Ft. Collins, CO, 6 College of Veterinary Medicine, University of Florida, Gainesville, FL, 7 Musculoskeletal Research Group, Veterinary Teaching Hospital, University of Liverpool, UK, 8 Burlington Veterinary Specialists, Burlington, VT, 9 Veterinary Defence Society, University of Cambridge, UK, 10 College of Veterinary Medicine, Cornell University, Ithaca, NY, 11 Georgia Veterinary Specialists, Atlanta, GA, 12 School of Veterinary Medicine, University of California-Davis, Davis, CA and 13 School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA Corresponding Author James L. Cook, DVM, PhD, Diplomate ACVS, Comparative Orthopaedic Laboratory, University of Missouri, 900 East Campus Drive Columbia, MO 65211 E-mail: cookjl@missouri.edu Submitted July 2009 Accepted March 2010 DOI:10.1111/j.1532-950X.2010.00763.x We propose standardized definitions and criteria for docu- menting subjective results for clinical orthopedic studies in veterinary medicine. To our knowledge, no common termi- nology or basis for describing results in this manner has been published. This lack of standardization limits our abilities to communicate study results in a consistent manner, interpret data appropriately, and compare results across studies, cen- ters, and techniques. An initial step toward addressing these deficiencies is to provide clear definitions and criteria for time frames of data collection, subjective outcomes, and compli- cations. These definitions and criteria are recommended for use based on consensus among the authors who have expe- rience and expertise in small animal and equine orthopedic clinical research. Our hope is that this terminology will be implemented so that data collection and reporting are more consistent and effective in veterinary orthopedic reports. BACKGROUND Before proposing new definitions and criteria, it is impor- tant to review those already established that are relevant to this discussion. The definitions and criteria we propose are designed for application to clinical studies. Clinical studies are those with subjects that are privately owned animals evaluated for epidemiologic, diagnostic, prophylactic, and/ or therapeutic factors or effects. Longitudinal studies collect data over a period of time and can be used to determine incidence, whereas cross-sectional studies examine cases at a single time point and can be used to determine preva- lence. Retrospective clinical studies examine data collected or determined before study initiation or for which the cri- teria for data collection and analyses were not established a priori, that is, the outcome of interest has already occurred at the time the study is initiated. Prospective clinical studies are those for which these criteria are established before study initiation and data are collected and analyzed as determined before starting the study. For all types of clinical studies, controls are a defined group of animals that are not exposed to the major variable in the study (negative control), are exposed to a sham treat- ment or placebo (negative control), are exposed to the major variable without receiving the treatment of interest Veterinary Surgery 39 (2010) 905–908 c  Copyright 2010 by The American College of Veterinary Surgeons 905