Effect of Knee Brace Type on Braking Response Time During Automobile Driving

Purpose: To assess driving ability (brake response time [BRT]) with commonly used knee braces. Methods: Sixty-four healthy participants (32 women and 32 men) participated in our study. BRT was assessed using a custom-made driving simulator. We assessed BRT for 5 different commonly used knee braces (right leg) used in 9 different settings: without a knee brace (control group); with a typical postoperative knee brace with adjustable range of motion (ROM) and the settings of 0 degrees to 30 degrees, 0 degrees to 60 degrees, 0 degrees to 90 degrees, and 20 degrees to 90 degrees (extension and flexion); and with an unloading knee brace for moderate to severe unicompartmental osteoarthritis, an orthosis for ligament instabilities, a knee brace for patellofemoral disorders, and an elastic knee bandage. Results: The 64 participants (mean age, 33.5 years) showed significantly impaired BRT with the typical postoperative brace set at an ROM of 0 degrees to 30 degrees (673 milliseconds, P <.001), ROM of 0 degrees to 60 degrees (629 milliseconds, P <.001), ROM of 0 degrees to 90 degrees (607 milliseconds, P = .001), and ROM of 20 degrees to 90 degrees (602 milliseconds, P = .005) compared with the control group. However, no such impaired BRT was found for any other investigated knee brace. Conclusions: Right-sided ROM-restricting knee braces involve significant impairment of BRT in healthy participants. No such prolonged BRT was found for a patellofemoral realignment brace, a ligament brace, a valgus/osteoarthritis brace, or an elastic knee bandage. However, our findings should be viewed in light of the limitations of the study, which are (1) the lack of a defined decrease in BRT that could lead to an accident and (2) uncertainty of whether the statistical differences are also clinically important.