Evaluation of the knee instability in anterior cruciate ligament injury using a newly developed three dimensional motion analysis

我们用一种新颖的方法研究了前交叉韧带（ACL）损伤的三维膝关节力学。提出了一种基于皮肤标记的运动分析技术（点聚类技术）。研究对象为女性7名，男性5名，诊断为单侧前交叉韧带损伤，拟行重建手术。平均伤后时间27.5个月（2 ~ 120个月）。在获得知情同意后，采用点聚类技术测量膝关节运动学，在下肢和髂骨的每个节段上放置21个皮肤标记，并采用三维运动分析系统，由5个光电摄像机、测力板和PC组成。每个受试者进行三项活动；水平行走、跑步和侧切到被测肢体的对侧。对ACL缺陷患者的健康侧也进行了评估以进行比较。在慢跑和切割活动中，ACL缺陷（ACLD）膝关节在站立中期有屈曲减少的趋势，但在这些活动中没有明显差异。行走时，胫骨旋转无明显差异。在90度旋转时，五种活动中旋转角度的量最大，但ACLD与健康膝关节的运动模式相似。在慢跑运动中，也未见显著差异。但在切割过程中，随着胫骨向外旋转，ACLD倾向于抓住地面，特别是在90度切割时，在脚跟撞击和脚趾脱落之前观察到显著差异。然而，在每次活动中，ACL缺陷侧和健康侧的胫骨旋转总量无显著差异。总之，我们的新方法（点簇技术）是评估膝关节动态不稳定的有效工具，如前交叉韧带损伤。

We investigated three dimensional knee mechanics in anterior cruciate ligament (ACL) injury using a novel method. A skin marker based motion analysis technique (Point Cluster Technique) was developed. The subjects were 7 women and 5 men, diagnosed as unilateral ACL injury and were going to have the reconstruction surgery. The average time past injury was 27.5 months (2-120 months). After obtaining the informed consent, the knee kinematics were measured using the point cluster technique, where 21 skin markers were placed on the each segment of lower limbs and iliac crest, and with 3-dimensional motion analysis system, consisted of 5 optoelectronic cameras, a force plate and PC. Each subject performed three activities ; level walking, running, and side cutting to the contralateral side of the measured limb. The healthy side of the ACL deficient patients were also evaluated for comparison. In jogging and cutting activities, ACL deficient (ACLD) knees showed the tendency that the knee flexion decreased in mid-stance phase, but no significant difference was seen in these activities. In walking, no obvious difference was seen about tibial rotation. In 90 degrees pivoting, the amount of rotation angle was the largest in the five activities, but ACLD and the healthy knees had similar motion pattern. During jogging motion, no significant difference was seen either. But during cutting maneuver, ACLD tended to catch the ground as the tibia more externally rotated, and especially in 90 degrees cutting, significant difference was observed at heel strike and just before toe off. However significant difference between ACL deficient and healthy side was not observed in total amount of tibial rotation during each activity. In conclusion, our new method (point cluster technique) is an useful tool to evaluate dynamic knee instability in knee patients such as ACL injury.