Anterior-posterior Mobility Of The Talus With Chronic Ankle Instability

Abstract

1074 BACKGROUND: Mechanical ankle instability is one of the purported causes of chronic ankle instability (CAI). There have been numerous contributors to mechanical ankle instability reported in the literature. Hypermobility and most recently, hypomobility, are two common entities associated with mechanical ankle instability. However, the effect of hypermobility or hypomobility of the talus on CAI has not been fully elucidated. PURPOSE: To determine the anterior-posterior mobility of the talus in subjects with CAI. METHODS: Fifteen subjects with unilateral CAI, and fifteen subjects with no previous history of ankle injury participated in this study. Anterior talar laxity was assessed with manual anterior drawer test and anterior stress radiographs. Posterior talar hypomobility was assessed with a series of two posterior talar glide tests. Comparisons were made between the CAI and control groups and within sides of both groups. RESULTS: The CAI group (mean = 11.4 + 5.4 mm) had significantly more anterior talar displacement on both their ankles as measured on the stress views than did the control group (mean = 6.7 + 4.7 mm). Interestingly, there was very little side to side difference between the involved and uninvolved ankles of the CAI group (11.5 mm vs. 11.3 cm). There were no significant differences involving either of the posterior talar glide measures or the manual anterior drawer test. CONCLUSIONS: An increased amount of anterior talar mobility was demonstrated in the CAI group. Although all of our subjects reported unilateral CAI, increased laxity was present in both the unstable and healthy ankle.