OBJECTIVETo 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.

METHODSFrom 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 cause II 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(1) The lateral stress results of tibiotalar joint showed the displacement by Evans procedure (group B) was greater than other groups (P < 0.0001). There were no significant differences between group A and C (P > 0.05). (2) The lateral stress results of subtalar joint showed the displacement by Evans procedure (group B) was greater than other groups (P< 0.0001). There were no significant differences between group A and C (P > 0.05).

CONCLUSIONAnkle 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.