The Effects of Hip and Spine Orthoses on Braking Parameters: A Simulated Study With Healthy Subjects.

BACKGROUND: Although a person's fitness to drive has gained more attention over the past few years, investigations have focused mainly on postsurgical (eg, hip arthroplasty) driving performance. Few data are available on how orthoses affect the ability to perform an emergency stop. OBJECTIVE: To determine whether common lumbar and hip orthoses impair driving performance by increasing brake response time and weakening brake force (BF). DESIGN: Crossover repeated measures design. SETTING: University hospital. PARTICIPANTS: A crossover, repeated-measures design was used to test 30 healthy volunteers with and without each of the orthoses in random order. METHODS: A custom-made simulator was created from a car cabin fitted with measurement equipment to record braking parameters under realistic spatial constraints. MAIN OUTCOME MEASUREMENTS: Reaction time (RT), foot transfer time (FTT) (these 2 together: brake response time), and maximum BF. RESULTS: Although spine orthoses lead to statistically significant increases in RT (Vertebradyn-Strong, P = .002; Horizon 637 LSO, P = .32; and SofTec Dorso, P = .013), this effect was not observed in hip orthoses, where instead FTT was prolonged (DynaCox and Hohmann-like orthosis, P < .001). BF was not significantly altered in any of the orthoses. CONCLUSIONS: This study demonstrates that hip and spine orthoses lead to impaired driving performance. Depending on the type of immobilization, this effect mostly increases RT or FTT, lengthening total stopping distances by up to half a meter at 100 km/h. However, in the absence of an underlying pathological condition in individuals with orthoses, their braking performance should be sufficient to continue driving.

How do ankle braces affect braking performance? An experimental driving simulation study with healthy volunteers.

BACKGROUND: Fitness to drive a car has been investigated increasingly over recent years. However, most research has focussed on perioperative driving performance, and few data are available on how orthoses influence the ability to perform an emergency stop. This study investigated the effect of 4 common ankle braces (Kallassy, CaligaLoc, Air-Stirrup, ASO) on reaction time, foot transfer time (together: brake response time) and brake force. The hypothesis was that wearing these braces on the right ankle impairs braking performance, specifically by increasing foot transfer time, but also by altering brake force. METHODS: A car cabin was set up with measurement equipment to register reaction time, foot transfer time, brake response time and brake force under realistic spatial constraints. A crossover repeated measures design was used to test 30 healthy volunteers with and without each of the braces. RESULTS: All 4 braces resulted in statistically significantly increased foot transfer time (p < 0.001), compared with measurements without a brace. Reaction time with a brace was significantly prolonged, with the exception of the Kallasy. Brake force was not statistically significantly impaired. CONCLUSION: This study demonstrates that ankle braces lead to impaired braking performance. Depending on the type of brace, a stopping distance increase of more than 1 m at 100 km/h can be expected.