Kinematics analysis of ankle inversion ligamentous sprain injuries in sports: 2 cases during the 2008 Beijing olympics

Ankle inversion ligamentous sprain is one of the most common injuries encountered in sports.4,5 A precise description of the injury situation is a key component to understanding the injury mechanism.2 However, quantitative analyses on injury cases with calibrated video recording are available only under rare circumstances.19 Previously, qualitative analysis of joint biomechanics was reported on ankle injuries based on visual inspection.1,8 Fong et al6 reported the first ever kinematics analysis of ankle inversion ligamentous sprain injury, which accidentally happened in their laboratory. However, the occurrence of recording ankle inversion ligamentous sprain injury in the laboratory is rare. Instead, injuries in sports are occasionally shown on television with multiple camera views, and those video recordings could be further analyzed to explain the cause of injury. To develop a novel biomechanical analysis to produce continuous measurement of joint kinematics from video recordings, Krosshaug and Bahr13 introduced a model-based image-matching (MBIM) motion analysis technique for investigating human motion from uncalibrated video sequences and employed the technique to determine the injury mechanism of anterior cruciate ligament (ACL) ruptures.14 In 2008, the International Olympic Committee (IOC) suggested an injury surveillance system for multisports tournaments.10 The injury surveillance system provides important epidemiological information. Junge et al11 reported the frequency, characteristics, and causes of injuries during the Beijing Olympic Games in 2008. Based on the information from the injury surveillance system, the injury incidents could be matched with the televised video recordings. Using the MBIM motion analysis technique, the ankle joint kinematics of 2 ankle ligamentous sprain injury cases could be reconstructed. The purpose of this article is to present the 3-dimensional (3-D) ankle joint kinematics of 2 ankle sprain cases detected by the injury surveillance system in the Beijing Olympic Games 2008.