INTRODUCTION:
In sports activities, damage to the knee joint meniscus is a relatively common occurrence, with particularly rare cases of the anterior horn Tear of the lateral meniscus of knee joint (AHLM).
According to past reports, the incidence of AHLM associated with sports activities is reported to be 2.5%, with soccer considered to carry a higher risk. Among soccer players, AHLM has been attributed to repetitive kicking motions involving knee joint extension. Therefore, we investigated the correlation between knee joint behavior during instep kicks involving knee joint extension and meniscus behavior, aiming to verify the factors contributing to the occurrence of AHLM.
METHODS:
23 university students were instructed to perform maximum effort instep kicks, and measurements were taken using a 3D motion analysis system. The analysis focused on calculating the knee joint extension and rotation angles from the moment of BI until the acceleration of the foot reached zero during the follow-through. The analysis was conducted using Vicon Nexus 2.16 software. Knee joint rotation was enhanced by adding markers to the inner side of the knee joint according to the conventional Plug-in-Gait marker set definition, and the segments were redefined using 3 points markers on the outer side of the thigh and lower leg, and the added marker on the inner side of the knee joint.
RESULTS:
A total of 43 instep kicks were performed. Knee joint hyperextension was observed in 69.8% of kicks, with an average angle of -7.0±4.1° and a maximum of -15.9°. The maximum extension position for each kick occurred between 0.052 to 0.072 sec after “Ball Impact” (BI). Furthermore, to increase the reliability of rotation angles, the rotation angle at the time of maximum knee flexion before the kick BI was normalized to 0°, and changes in rotation angles after BI were considered as knee joint rotation angles. As a result, the average maximum rotation angle after BI was -14.5±12.9° (average knee flexion angle of 35.1±7.5°), indicating external rotation. Additionally, 81.6% of external rotation was observed during the period of 0.052 to 0.072 sec after BI, with an average angle of -7.5±1.3°.
CONCLUSION:
It is known that the knee joint meniscus moves forward with knee joint extension and influenced by the “Screw Home Movement function” during extension, undergoes external rotation, causing the meniscus to move anteriorly and laterally. AHLM are frequently observed in soccer players, especially those involving instep kicks that accompany knee joint extension. The repetitive nature of this motion is believed to be a contributing factor to AHLM. The results of this study confirm that knee joint external rotation increases significantly at this moment of knee joint hyperextension in the kicking leg during instep kicks. This supports the conclusion that the kicking motion (instep kick) contributes to the induction of AHLM.