Grassi Alberto, Tosarelli Filippo, Agostinone Piero, Macchiarola Luca, Zaffagnini Stefano, Della Villa Francesco
IIa Clinica Ortopedica e Traumatologica, IRCSS Istituto Ortopedico Rizzoli, Bologna, Italy.
Education and Research Department, Isokinetic Medical Group, FIFA Medical Centre of Excellence, Bologna, Italy.
Sports Health. 2020 Sep/Oct;12(5):462-469. doi: 10.1177/1941738120936673. Epub 2020 Jul 22.
The mechanisms of noncontact anterior cruciate ligament (ACL) injuries are an enormously debated topic in sports medicine; however, the late phases of injury have not yet been investigated.
A well-defined posterior tibial translation can be visualized with its timing and patterns of knee flexion after ACL injury.
Case series.
Level 4.
A total of 137 videos of ACL injuries in professional male football (soccer) players were screened for a sudden posterior tibial reduction (PTR) in the late phase of noncontact ACL injury mechanism. The suitable videos were analyzed using Kinovea software for sport video analysis. The time of initial contact of the foot with the ground, the foot lift, the start of tibial reduction, and the end of tibial reduction were assessed.
A total of 21 videos exhibited a clear posterior tibial reduction of 42 ± 11 ms, after an average of 229 ± 81 ms after initial contact. The tibial reduction occurred consistently within the first 50 to 60 ms after foot lift (55 ± 30 ms) and with the knee flexed between 45° and 90° (62%) or more than 90° (24%).
A rapid posterior tibial reduction is consistently present in the late phases of noncontact ACL injuries in some male soccer players, with a consistent temporal relationship between foot lift from the ground and consistent degrees of knee flexion near or above 90°.
This study provides insight into the late phases of ACL injury. The described mechanism, although purely theoretical, could be responsible for commonly observed intra-articular lesions.
非接触性前交叉韧带（ACL）损伤机制是运动医学中一个备受争议的话题；然而，损伤的后期阶段尚未得到研究。
ACL损伤后，明确的胫骨后移及其与膝关节屈曲时间和模式可以被观察到。
病例系列。
4级。
筛选了137段职业男性足球运动员ACL损伤的视频，以寻找非接触性ACL损伤机制后期阶段突然出现的胫骨后移（PTR）。使用Kinovea软件对合适的视频进行运动视频分析。评估了脚与地面初始接触时间、脚离地时间、胫骨后移开始时间和胫骨后移结束时间。
共有21段视频显示出明显的胫骨后移，平均在初始接触后229±81毫秒，后移时间为42±11毫秒。胫骨后移在脚离地后的前50至60毫秒内（55±30毫秒）持续出现，且膝关节屈曲角度在45°至90°之间（62%）或超过90°（24%）。
在一些男性足球运动员非接触性ACL损伤的后期阶段，始终存在快速的胫骨后移，且脚离地与膝关节屈曲接近或超过90°之间存在一致的时间关系。
本研究为ACL损伤的后期阶段提供了见解。所描述的机制虽然纯粹是理论性的，但可能是常见关节内损伤的原因。
