Driving brake reaction time following right ankle arthrodesis.

ABSTRACT

BACKGROUND: The purpose of this study was to compare the brake reaction time of patients with successful right ankle fusion to normal volunteers without an ankle fusion. METHODS: Ten patients who underwent successful right ankle arthrodesis were evaluated using a driving simulator as well as an in-shoe pedobarographic measuring system. Brake reaction time, braking force, peak pressure, contact area, and the center of force between the foot and the brake pedal were recorded. SF-12 scores were obtained from all study patients. A control group of ten age-matched individuals without ankle fusion was included for comparison. RESULTS: Mean brake reaction time for the ankle fusion group (0.42+/-0.14 seconds) was significantly slower than for the control group (0.33+/-0.06 seconds) (p=0.03). The center of force was consistently isolated to the forefoot in the ankle fusion group compared to controls who distributed the center of force over both the forefoot and midfoot. There was no significant difference between the ankle fusion and control groups with respect to braking force, peak pressure, or contact area. CONCLUSION: The mean brake reaction time following successful right ankle arthrodesis was significantly slower than that of normal controls. However, the fusion group time was still below the threshold for what is defined as a safe brake reaction time by the United States Federal Highway Administration.