The three-dimensional passive support characteristics of ankle braces.

Studies of the passive support provided by ankle braces have focused primarily on inversion support. The goal of this study was to develop a technique to measure the support provided by ankle braces in all rotational directions and to use this technique to compare four common braces (Ascend, Swede-O, Aircast, and Active Ankle). For this purpose, a 6 degrees-of-freedom linkage was used to measure the flexibility of the ankle complex in 10 healthy subjects. Each subject was tested without brace support and with each of the four braces. Testing was repeated on each subject on two different occasions. The angular displacement at specified moment values and the four segmental flexibility values obtained from the loading portion of the moment-angular displacement data were used in the data analysis. Repeated measure analysis of variance followed by a Student Neuman-Keuls test at p < 0.05 was performed. This statistical analysis was used to identify significant differences among the braces and differences between each brace and the no brace condition. Each of the four braces provided significant support in inversion, eversion, and internal rotation, but the amount of support varied significantly among the braces. In external rotation, only the stirrup braces provided significant support. The braces also varied significantly in the amount of interference with dorsiflexion and plantar flexion. Clinicians may be assisted by objective data on the amount and nature of passive support when prescribing braces to their patients.