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

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

PM R. 2015 Jun 12;

Authors: Hofmann UK, Thumm S, Jordan M, Walter C, Rondak IC, Ipach I

Abstract

BACKGROUND: Although fitness to drive has gained more attention over the past few years, investigations have mainly focused on postsurgical (eg, hip arthroplasty) driving performance. Little 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 (BRT) 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: BRT), and maximum BF.

RESULTS: Although spine orthoses lead to statistically significant increases in RT (Vertebradyn-strong, P = .002; Horizon 637 LSO, P = 0.32; 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.

PMID: 26079866 [PubMed - as supplied by publisher]