ACL injuries: Do we know the mechanisms?

s were then peer-reviewed for scientific merit and relevance to the retreat topic. There was a 50% increase in the number of abstract submissions this year. In the end, 33 abstracts were accepted. These were grouped into sessions addressing structural, neuromuscular, biomechanical, and hormonal factors that may influence the gender bias in ACL injury incidence. It was interesting to note that the majority of abstracts submitted were in the area of neuromuscular and biomechanical factors, with only a few in the areas of structural and hormonal factors. This suggests a trend in the research focus towards the more modifiable factors. The retreat was cohosted by Kentucky Sports Medicine and Drayer Physical Therapy Institute and sponsored by DonJoy, Aircast, Bluegrass Bracing, and Smith and Nephew. To accommodate the increase in number of high-quality abstracts, the meeting was extended to 2 full days. The retreat was attended by both clinicians and scientists with a common interest in the ACL injury gender bias. The 60-plus participants included registrants from across the United States as well as Canada and Australia. As with the previous retreats, the group consisted of physicians, physical therapists, athletic trainers, and scientists in the areas of biomechanics, motor control, and neuromuscular function. 1 University of Delaware, Newark, DE. 2 Drayer Physical Therapy Institute, Hummelstown, PA. 3 Kentucky Sports Medicine Center, Lexington, KY. 4 University of Kentucky, Lexington, KY. GuesT ediTors: irene davis, PT, PhD1,2 • Mary LLoyd ireLand, MD3 • saori Hanaki, MS, ATC4 Thirty percent of the participants in the 2006 retreat were participants in a previous retreat as well. The format of the meeting included 1 keynote presentation per day, along with 15-minute podium presentations made by some of the participants. The keynote presenters were chosen for their scientific contribution to the understanding of factors associated with the gender bias seen in the incidence of ACL injuries. Ton van den Bogert, PhD, from the Department of Biomedical Engineering at the Cleveland Clinic gave the first keynote titled “ACL Injuries: Do We Know the Mechanisms?” The second keynote presenter was William Garrett, MD, PhD, from the Department of Orthopedics at Duke University, whose talk was titled “Anterior Cruciate Ligament Injury Mechanisms and Risk Factors.” Following all of the presentations, a consensus development session was held. In the following pages, you will find the consensus statement and an abstract on each of the 33 presentations made at the conference, organized by the topics listed above. t ACL Injuries—The Gender Bias Research Retreat III ACL Supplement: Consensus Statement T he consensus statement was developed with input from all of the participants. Once all papers were presented, the participants formed into groups, based upon each of the factors discussed during the meeting. As with previous retreats, the consensus was formed through discussion of what we know, which was grounded in the recent literature and information presented at the current retreat. The group then identified what is still unknown (what we don’t know) about each factor’s contribution to the gender bias. This led to the final part of the consensus, in which suggestions for future research directions were made. Each group was charged with providing a draft consensus statement that was then presented to the group for further discussion. Participants agreed that the consensus should be viewed as the present state of thought about anterior cruciate ligament (ACL) injuries, based upon current knowledge. As with previous retreats, it was acknowledged that what we know will likely evolve with time. Participants continue to agree that, while there is a gender bias in ACL injuries, some of the identified factors (structural, neuromuscular, and biomechanical) may not be purely gender specific. Some males may also exhibit these factors and be at greater risk for ACL injury. The question of whether females should move like men or whether there is a different optimal pattern for them was also again discussed, but not resolved. However, it is apparent that the current movement patterns of females place them at increased risk for injury. Finally, there was a group consensus that more ecological studies are needed to better replicate the environments in which the injuries typically occur. New to this year’s retreat were presentations on the use of 2-dimensional techniques to assess movement patterns. These approaches are important as they can be easily implemented in the clinic. They also provide a means to conduct large-scale screening studies to predict injury risk and assess the effect of intervention programs. Another new topic discussed this year was gender differences in variability of movement. This is an emerging topic in the biomechanics community, with ongoing discussions of the importance of variability in reducing injury risk. However, excessive vari1 University of Delaware, Newark, DE. 2 Drayer Physical Therapy Institute, Hummelstown, PA. 3 Kentucky Sports Medicine Center, Lexington, KY. 4 University of Kentucky, Lexington, KY. GuesT ediTors: irene davis, PT, PhD1,2 • Mary LLoyd ireLand, MD3 • saori Hanaki, MS, ATC4 ability of movement may be detrimental. Therefore, the optimal level of variability requires further defining. Following are the sections of the consensus statement for each of the factors thought to be associated with the ACL injury gender bias, as well as for the section on intervention programs. We realize that these lists are not all inclusive; however, they do represent the collective opinions of the participants in this retreat. Many of the questions from the previous retreat remain unanswered. It is our hope that this consensus statement will promote research studies in the suggested areas so that some of these gaps in the literature might be filled by the next ACL research retreat. BioMeCHaniCaL FaCTors