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Injury mechanism of knee medial collateral ligament: An online systematic video analysis



The medial collateral ligament (MCL), one of the main stabilizers of the knee, is also the most injured ligament of the knee. Isolated MCL injuries are common in young men who play contact sports. It was hypothesized that MCL rupture in professional athletes develops with a specific injury mechanism. Furthermore, body posture at the time of injury varies in different sports.



On May 15, 2021, “knee medial collateral injury” and “MCL injury” were entered in a YouTube® search. The inclusion criteria were to verify that the video was compatible with the injury, that the video included the foot, ankle, knee, hip, and the whole body at the time of injury, and that image quality was sufficient to detect the mentioned body parts. Exclusion criteria were non-MCL knee injuries, insufficient images, poor video quality, and additional injuries with MCL.



Of the 23 injuries included in the study, 22 (95.7%) were male and 1 was female (4.3%). The distribution of activities in which injuries occurred was seven basketball (30.4%), four American football (17.4%), four ice hockey (17.4%), three soccer (13.0%) one water ski (4.3%), one skateboard (4.3%), two-track and field (8.6%), and one wrestling (4.3%). In 18 cases (78.3%), the injury occurred by contact. Of these, 16 were caused by direct contact (69.6%) and two by indirect contact (8.7%).



Isolated MCL injury occurs when valgus force is applied with the trunk flexed and turned towards the injured side, the hip abducted and slightly flexed, and the knee slightly flexed. The majority of these cases occur after a direct blow to the lateral knee.
