Purpose: Until now no experimental study has evaluated the effect of orthopedic immobilizations of the lower right limb on driving performances. Clinicians and legislators therefore cannot appropriately advise patients with this type of treatment on their driving capabilities and put forth recommendations for road safety.

Method: An experimental study of the effect of orthopedic immobilizations of the lower right limb on driving performances has been conducted at the Research Center on Aging of the Sherbrooke Geriatric University Institute. The breaking capabilities of forty-eight healthy volunteers were tested in three conditions: wearing their usual running shoes and two types of immobilization, namely the walking cast (Delta-Cast Conformable, BSN Medical, Leuven, Belgium) and the foam pneumatic walker (Aircast, Vista, CA). The order in which each condition was tested was randomly determined for each volunteer. A custom driving simulator was used to measure the force applied on the break pedal and the breaking time using the software LabVIEW (National Instruments, Austin, TX). In addition, each volunteer completed a socio-demographic survey, a brief physical exam and two clinical tests (stepping and standing).

Results: The average maximum breaking forces exerted by the volunteers with the walking cast, the foam walker and the shoes are 275,4 lb, 287,2 lb and 293,8 lb respectively. The two significant differences are between the walking cast and the shoes (18,4 lb, p< 0,001) and between the walking cast and the foam walker (11,8 lb, p< 0,001). The measured average breaking reaction times are (from the slowest to the fastest) 619 ms, 609 ms, and 580 ms with the foam walker, the walking cast and the shoes respectively. The two significant differences are between the shoes and the foam walker (39 ms, p< 0,001) and between the shoes and the walking cast (29 ms, p< 0,001). The results of this study also confirm the correlation between the measured breaking reaction times and the stepping and standing clinical test (p< 0,05).

Conclusion: Although this study observed statistically significant changes in breaking force and reaction time in volunteers wearing two common