Oslo Sports Trauma Research Center

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Information about project titled 'Mechanisms of ACL injury inbasketball: video analysis of 39 cases'

Mechanisms of ACL injury inbasketball: video analysis of 39 cases

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Project status: Published
Project manager: Tron Krosshaug
Supervisor(s): Roald Bahr
Coworker(s): Atsuo Nakamae, Barry Boden, Lars Engebretsen, Gerald Smith, James Slauterbeck, Tim Hewett


Although much attention has focused on non-contact ACL injuries in team sports, the exact mechanism of these injuries remains unclear. Video footage of injury situations represents objective sources of information on the kinematics involved in the injury mechanism and may therefore be a valuable tool. However, with the exception of the study of Olsen et al. who attempted to quantify the joint kinematics, most descriptions were qualitative, and the results are difficult to compare across studies. Furthermore, apart from one study on team handball, previous video analyses have only investigated a limited number of cases from mixed sports. The purpose of this study was therefore to describe the mechanisms of ACL injury in basketball based on videos of injury situations.


Methods: Six international experts performed visual inspection analyses of 39 videos (17 male, 22 female) of ACL injury situations from high school, college and professional basketball games. Two pre-defined time points were analyzed; initial ground contact and 50 ms later. The analysts were asked to assess the playing situation, player behaviour and joint kinematics.


Results: There was contact at the assumed time of injury in 11 of the 39 cases (five males, six females). Four of these cases were direct blows to the knee, all in men. Eleven of the 22 female cases collided or were pushed by an opponent prior to the time of injury. The estimated time of injury, based on the group median, ranged between 17 and 50 ms after initial ground contact. The mean knee flexion angle was higher in females compared to males, both at initial contact (15° vs. 9°, p=.034) as well as 50 ms later (27° vs. 19°, p=.042). Valgus knee collapse occurred more frequently in females compared to males (relative risk: 5.3, p=.002).


Conclusion: Females landed with significantly more knee and hip flexion and had a 5.3 times higher relative risk of sustaining a valgus collapse compared to males. Movement patterns were frequently perturbed by opponents.