Background: The effects of immobilization of the right lower limb on driving performance are unknown. Therefore, clinicians and legislators cannot put forth recommendations for road safety for patients requiring such immobilization. The objective of the present study was to evaluate the effect of two orthopaedic immobilization devices on the braking performances of healthy volunteers under simulated driving conditions.
Methods: The braking performances of forty-eight healthy volunteers were evaluated under three conditions: wearing a running shoe, wearing a walking cast, and wearing an Aircast Walker on the right lower limb. A computerized driving simulator was used to measure the maximum force applied on the brake pedal during braking as well as the braking reaction time and the total braking time during emergency braking with and without a distractor.
Results: The mean braking forces applied with the shoe, the walking cast, and the Aircast Walker were 293.8, 275.4, and 287.2 lb (133.3, 124.9, and 130.3 kg), respectively. The value with the walking cast was significantly lower than that with the shoe or Aircast Walker (p < 0.0001); there was no difference between the shoe and the Aircast Walker. The adjusted mean braking reaction times during emergency braking without a distractor were 0.580 second (shoe), 0.609 second (cast), and 0.619 second (Aircast Walker). The value with the running shoe was significantly lower than that with either type of immobilization (p < or = 0.0001). With a distractor, the mean braking reaction time was shorter with the running shoe than it was with either form of immobilization (p < or = 0.0001); the mean time was also shorter with the walking cast than it was with the Aircast Walker (p = 0.003). During both emergency braking tasks (with and without a distractor), the mean total braking time was shorter with the shoe than it was with either type of immobilization (p < 0.0001). With a distractor, the adjusted mean total braking time was shorter with the walking cast than it was with the Aircast Walker (p = 0.035).
Conclusions: Immobilization of the right lower limb affects the braking force as well as the braking reaction time and total braking time during emergency braking by healthy volunteers. While these changes are significant, their impact on the ability to drive safely during emergency braking situations is questionable. Future research into the impact of such immobilization on the emergency braking performances of patients is warranted to confirm these observations.