Objective: To analyze characteristics and related factors of the plantar pressure during the level walking and single leg standing in the chronic ankle instability (CAI) individuals.
Methods: From April 2019, 75 CAI individuals and 40 healthy individuals were enrolled in this study. Both of the static and dynamic plantar pressure were measured during six times level walking and three times single leg standing testing. The data including peak force, time to peak force in various foot contact areas and the time to boundary (TTB) and velocity of center of pressure (COP) were measured and compared between the affected side and the unaffected side and between the CAI cases and the healthy individuals. The correlations between the plantar pressure and the gender, Beighton score, affected side and body mass index (BMI) were analyzed.
Results: The characteristics of plantar pressure distribution in the CAI individuals included: (1) During the level walking, the affected side showed the similar pressure contribution as the unaffected side (P>0.05). While compared with healthy individuals, there was a significantly higher peak force in the 5th metatarsal area (t=-3.86, P=0.03) of the affected side, lower peak force in the 1st (t=2.99, P=0.02), 2nd metatarsal head areas (t=2.09, P=0.01) of the affected side, medial hindfoot areas of both sides (affected, t=2.33, P=0.01; unaffected, t=3.74, P=0.02) and toes areass of both sides (affected, t=2.23, P=0.01; unaffected, t=3.28, P=0.02) and a delay to peak force in the 4th metatarsal head area (t=3.33, P=0.01) of the affected side. (2) During the single leg standing, the CAI individuals showed significantly worse balance control in the anterior/posterior direction (P < 0.05) and lateral/medial direction (P < 0.05) compared with the healthy controls, and the affected side had more severe balance control deficit in the lateral/medial direction (P < 0.05). (3) The women (P < 0.05) and the individuals with higher Beighton scores (P < 0.05) showed worse balance control deficit in the lateral/medial direction.
Conclusion: CAI individuals showed significantly a more lateral shifted plantar distribution during the level walking compared with the healthy individuals and the tendency was worse on the affected sides, and showed worse balance control in the anterior/posterior direction and lateral/medial direction during the single leg standing. The women and those with generalized ligament laxity showed significantly worse balance control.
目的: 探讨慢性踝关节不稳(chronic ankle instability，CAI)患者在步行与单足支撑时的足底压力分布特点及其相关因素。
方法: 纳入75例CAI患者及40例正常人，对步行及单足站立时的足底压力参数进行对比分析，测量指标为足底每个区域的压强峰值、达峰时间、边界时间(time to boundary，TTB)和压力中心(center of pressure，COP)偏移速度等系列指标。评估CAI患、健侧差异以及与正常对照组的差异，并分析存在差异的足底压力指标与患者年龄、性别、侧别、体重指数、Beighton评分的相关性。
结果: CAI患者患、健侧步行时均化峰值压力差异无统计学意义，但是与正常人相比，患侧的第一跖骨(t=2.99，P=0.02)和第二跖骨(t=2.09，P=0.01)、双侧的足跟内侧(患侧t=2.33，P=0.01；健侧t=3.74，P=0.02)和足趾区峰值压力(患侧t=2.23，P=0.01；健侧t=3.28，P=0.02)较小，患侧的第五跖骨区域(t=-3.86，P=0.03)的均化峰值压力较大，且患侧第四跖骨达峰时间较晚(t=3.33，P=0.01)。患侧的内外侧TTB最小值(t=-2.67，P=0.03)、极小值的平均值(t=-3.54，P=0.02)和标准差(t=-2.86，P=0.04)均明显小于健侧，与正常人相比，TTB系列与压力中心系列指标提示患、健侧在内外向和前后向均存在明显的稳定性缺陷(P < 0.05)。女性、Beighton评分高的CAI患者内外向稳定性缺陷更明显(P < 0.05)。
结论: CAI患者在平地步行时患、健侧的足底压力分布特征与正常人存在明显差异，患侧足底COP明显向足外侧偏移。单足支撑时，患侧前后向及双侧的内外向姿势控制稳定性均明显弱于正常人，女性及伴有全身韧带松弛症的CAI患者内外向稳定性缺陷更明显。
Keywords: Ankle joint; Foot pressure; Joint instability; Ligament injury.