[Biomechanical comparison of Evans procedure and Chrisman-Snook technique for the treatment of II degree lateral collateral ligament of ankle joint].

Objective:To measure the stability of Evans procedure and Chrisman-Snook technique in the treatment of Ⅱ degree lateral collateral ligament of ankle joint,and provide basis for treatment and prognosis.Methods:From July 2008 to June 2009,18 frozen corpes were collected,including 10 males and 8 females,with an average age of fresh 39.3±11.2 years.The frozen corpes were randomly divided into three group,including normal controls(group A),Evans procedure(group B)and Chrisman-Snook technique(group C),6 specimens in each group.Anterior talofibular ligament and calcaneofibular ligament were cut off to causeⅡ degree lateral collateral ligament in group B and C.Evans procedure or Chrisman-Snook technique were applied to restore lateral collateral ligament,and measure biomechnics.The displacement of tibiotalar joint and subtalar joint were observed.Results:①The lateral stress results of tibiotalar joint showed the displacement by Evans procedure(group B) was greater than other groups(P0.000 1).There were no significant differences between group A and C(P0.05).②The lateral stress results of subtalar joint showed the displacement by Evans procedure(group B) was greater than other groups(P0.000 1).There were no significant differences between group A and C(P0.05).Conclusion:Ankle instability is caused by ankle joint lateral collateral ligament injury.Chrisman-Snook technique is better than Evans procedure in stability on the early stage of ankle joint restoration,and conform to principle of biomechanics.