Tap test used for judging syndesmosis stability during ankle fracture surgery

Abstract

Objective To evaluate the efficacy and consistency of tap-test used for judging the stability of lower tibiofibular syndesmosis during ankle fracture operations.Methods Fifty-two patients were enrolled in our study who had received surgery from June 2012 to February 2013 for ankle fracture with the lower tibiofibular syndesmosis involved.They were 28 males and 24 females,with an average age of 40.4 years (range,19 to 56 years).After the bone structure was fixated,2 individual surgeons evaluated the stability of the lower tibiofibular syndesmosis respectively using 3 different methods:external rotation stress,hook and tap tests.The positive detection rate,compound positive detection rate and detection inconsistency of each method were calculated for both surgeons.Results In the external rotation stress test,the 2 surgeons detected 10 (19.2 ％) and 8 (15.4％) unstable cases respectively,with inconsistency in 6 cases (11.5％) and a compound positive detection rate of 23.1％.In the hook test,the 2 doctors diagnosed 11 (21.2％) and 12 (23.1％) unstable cases respectively,with inconsistency in 5 cases (9.6％) and a compound positive detection rate of 26.9％.In the tap test,both of the 2 doctors diagnosed 14 (26.9％) unstable cases respectively,with no inconsistency and a compound positive detection rate of 26.9％.There was no significant differences in the positive detection rate among the 3 methods (P ＞ 0.05),but the detection consistency of tap test was significantly higher than the other 2 methods (P ＜ 0.05).Conclusion Tap test is a useful method to evaluate the stability of the lower tibiofibular syndesmosis during ankle fracture operation,as it has very good sensibility and consistency and needs no radiological examination. Key words: Ankle joint; Fracture, bone; Joint instability; Exercise test