下胫腓联合韧带不同程度损伤的稳定性研究

Effects of injuries to the distal tibiofibular syndesmosis on ankle stability

【摘要】目的通过在尸体标本上模拟下胫腓联合韧带损伤，明确不同程度的下胫腓韧带损伤对踝关节稳定性的影响。方法选取防腐尸体下肢标本10具，分别测量垂直加载500N压力、7种体位下（中立位、背伸位、跖屈位、内翻位、外翻位、内旋位、外旋位）下胫腓联合韧带完整状态（A组）、单纯前韧带断裂（B组）、前韧带＋后韧带断裂（c1组）、前韧带＋骨间韧带断裂（C2组）、全部韧带断裂＋切断骨间膜（〉5cm）（D组）时，下胫腓联合的分离距离、胫距关节接触面积、平均接触压强及峰值压强的变化。结果在中立位、背伸位、跖屈位、内翻位、外翻位、内旋位、外旋位时，A组、B组标本的下胫腓分离距离、胫距关节接触面积、平均接触压强及峰值压强组内比较差异均无统计学意义（P〉0．05）。C1组、C2组、D组在外旋及内翻应力位下，踝关节出现不稳定，下胫腓分离距离增宽均〉2mm，比其他5种体位均明显。与其他各体位比较，在外旋及内翻应力位下下胫腓分离距离、胫距关节接触面积、平均接触压强及峰值压强方面差异均有统计学意义（P〈0．05）。随着损伤的加重，下胫腓韧带的分离距离增大，接触面积逐渐缩小，平均压强增大，峰值压强增大，外旋位及内翻位更明显。A、B、c1、c2、D组下胫腓分离距离、胫距关节接触面积、平均接触压强及峰值压强变化趋势基本一致。结论不同程度的下胫腓联合韧带损伤在大部分体位下，踝关节能保持稳定，可满足普通人群的日常负重需求。但在外旋和内翻位下，会明显影响踝关节的稳定性。建议在中、重度韧带损伤时，需对下胫腓韧带修复固定，特别是对于踝关节要求更高的人群。

Objective To investigate the effects of injuries of various degrees to the distal tibiofibular syndesmosis on the ankle stability in cadaveric specimens of distal tibiofibular syndesmosis injury. Methods We used 10 cadaveric specimens of lower limbs for this experiment. The specimens were set in 7 different positions （neutral position, dorsiflexion, plantar flexion, varus, valgns, internal rotation and ex- ternal rotation） and then received axial force of 500 N. We measured separation distance of the distal tibiofibular syndesmosis （SD）, contact area of the tibiotalar joint （CA）, average contact pressure （CP） and peak pressure（PP） sequentially in all the specimens set at all the 7 positions in the following conditions： intact tibiofibular syndesmosis （group A）, rupture of the anterior tibiofibular ligament （group B）, rupture of the anterior and posterior tibiofibular ligaments （group C1）, rupture of the anterior and interosseous ligaments （group C2）, and rupture of all the ligaments and separation of interosseous membrane （ 〉 5 cm） （group D）. Results There were no significant differences in SD, CA, CP or PP within groups A and B between the 7 positions （ P 〉 0. 05） . At positions of external rotation and varus, ankle instability occurred in groups C1, C2 and D, with SD 〉 2 mm, obviously larger than in the other 5 positions. SI）, CA, CP and PP in positions of external rotation and varus were significantly different from those at the other 5 positions （ P 〈 0.05）. With increased injury, SD increased, CA reduced, CP and PP increased, particularly at positions of external rotation and varus. The similar changes in SD, CA, CP and PP were observed in groups A, B, C1, C2 and D. Conclusions The ankle can remain stable and meet the requrements of daily weight bearing in general population when the syndesmosis ligaments are injured to varioustents at most positions. However, ankle stability can be obviously affected at positions of external rotation and varus. We suggest that fixation of the tibiofibular ligaments should be necessary when the tibiofibular syndesmosis ligaments are injured to a moderate or severe extent, especially in those who require a high level of ankle activities.