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

采用一种新的方法对前交叉韧带损伤的膝关节三维力学进行了研究。提出了一种基于皮肤标记的运动分析技术(点聚类法)。受试者为女性7例，男性5例，诊断为单侧前交叉韧带损伤，行前交叉韧带重建手术。术后平均受伤时间27.5个月(2~120个月)。征得知情同意后，用点簇技术测量膝关节运动学，在小腿和髂骨各段各放置21个皮肤标记，并使用由5个光电摄像头、测力板和PC机组成的三维运动分析系统。每个受试者都进行了三种活动：水平行走、跑步和侧切至被测肢体的对侧。同时对ACL缺陷患者的健侧进行评估，以供比较。在慢跑和切割活动中，前交叉韧带缺陷(ACLD)膝关节在站立中期有屈膝下降的趋势，但这些活动没有显著差异。步行时，胫骨旋转度无明显差异。旋转90度时，5种活动中旋转角度最大，但ACLD和健康膝关节的运动规律相似。在慢跑运动中，也没有明显的差异。但在切割动作中，随着胫骨外旋的增加，ACLD更倾向于接地力，尤其是在90度切割时，在脚跟着地和脚趾离开之前观察到了显著的差异。但在每次活动中，前交叉韧带缺陷侧与健侧的胫骨旋转总量无显着性差异。总之，我们的新方法(点群技术)是评估膝关节动态不稳定性的有用工具，例如前交叉韧带损伤。

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.