闭合复位外固定架固定治疗合并下胫腓联合分离的旋前-外展型三踝骨折的稳定性研究

目的:评估闭合复位外固定架固定治疗合并下胫腓联合分离的旋前-外展型三踝骨折的稳定性。方法:将7对踝关节标本行间断骨钻孔后根据受伤机制施加暴力,制备旋前-外展型三踝骨折模型14踝,其中3对(6踝)踝关节标本合并下胫腓联合分离。将一侧踝关节标本先进行闭合复位外固定架固定,再进行切开复位接骨板内固定;另一侧踝关节标本先进行切开复位接骨板内固定,再进行闭合复位外固定架固定。每次复位固定后,先后对模型施加10 Nm、15 Nm、20 Nm的扭矩外旋足踝,通过在X线片上测定下胫腓联合间隙确定其稳定性。执行完一种固定方式的稳定性测试后,将标本上固定的外固定架或内固定物完全拆除,并将踝关节标本恢复至复位固定前的状态,然后进行另一种固定方式的稳定性测试。比较不同扭矩下两种固定方式对下胫腓联合间隙的影响。结果:造模后双侧踝关节下胫腓联合间隙比较,差异无统计学意义[(6.29±2.93)mm,(4.28±1.69)mm,t=0.378,P=0.540]。闭合复位外固定架固定和切开复位接骨板内固定的合并下胫腓联合分离的旋前-外展型三踝骨折,施加10 Nm、15 Nm、20 Nm扭矩后,两组下胫腓联合间隙的差异均无统计学意义[(5.72±2.46)mm,(5.29±3.58)mm,t=0.246,P=0.811;(5.69±2.72)mm,(6.98±3.05)mm,t=-0.773,P=0.458;(5.70±2.95)mm,(6.80±3.20)mm,t=-0.618,P=0.551]。结论:闭合复位外固定架固定治疗合并下胫腓联合分离的旋前-外展型三踝骨折,其稳定性与切开复位接骨板内固定相当。

A study of stability of closed reduction and frame external fixation in the treatment of pronation-abduction-type trimalleolar fractures combined with distal tibiofibular syndesmosis separation

Objective:To evaluate the stability of closed reduction and frame external fixation in treatment of pronation-abduction-type trimalleolar fractures combined with distal tibiofibular syndesmosis separation.Methods:The pronation-abduction-type trimalleolar fracture models(14 ankles)were made by applying violent force to ankle specimens(7 pairs)according to injury mechanism after intermittent bone drilling was performed,and distal tibiofibular syndesmosis separation was found in 3 pairs(6 ankles)of ankle specimens.One of a pair of ankle specimens was treated with closed reduction and frame external fixation,and then the treatment was replaced by open reduction and bone plate internal fixation;while the other one of a pair of ankle specimens was treated by the reversed sequence.After reduction and fixation,10,15 and 20 Nm-torques were applied to the models respectively to rotate the ankles outward,and then the stability was determined through measuring the distal tibiofibular syndesmosis interspaces on X-ray films.The two fixation methods were compared with each other in their effect on distal tibiofibular syndesmosis interspace under different torques.Results:There was no statistical difference in distal tibiofibular syndesmosis interspace between bilateral ankles after the modeling(6.29+/-2.93 vs 4.28+/-1.69 mm,t=0.378,P=0.540).For ankle specimens with pronation-abduction-type trimalleolar fracture and distal tibiofibular syndesmosis separation,there was no statistical difference in distal tibiofibular syndesmosis interspace between therapy of closed reduction and frame external fixation and therapy of open reduction and bone plate internal fixation after 10,15 and 20 Nm-torques were exerted on them respectively(5.72+/-2.46 vs 5.29+/-3.58 mm,t=0.246,P=0.811;5.69+/-2.72 vs 6.98+/-3.05 mm,t=-0.773,P=0.458;5.70+/-2.95 vs 6.80+/-3.20 mm,t=-0.618,P=0.551).Conclusion:Closed reduction and frame external fixation is similar to open reduction and bone plate internal fixation in stability in treatment of pronation-abduction-type trimalleolar fractures combined with distal tibiofibular syndesmosis separation.