I read with considerable interest the article "Lower-Extremity
Function for Driving an Automobile After Operative Treatment of Ankle
Fracture"
(2003;85:1185-9), by Egol et
al. I would like to thank the authors for their excellent research. Their
conclusion that, by nine weeks following internal fixation of a displaced
ankle fracture, total braking time returns to normal baseline values provides
good information with which we can counsel patients on postoperative
activities.
I noted that patients who had suffered injuries of only the right ankle
were tested on a computerized driving simulator that consisted of a brake and
accelerator pedal assembly. I appreciate that automobiles with an automatic
transmission are more common in North America; however, in the United Kingdom,
the majority of vehicles have a manual transmission, with the clutch
controlled with the left foot and ankle.
Previous research has been under-taken into clutch pedal usage, by Wang et
al., and the complex biomechanical model of the control of pedal force
direction has been
determined1. The
movement during clutch pedal operation may be controlled by proprioceptive
feedback related to the force applied and leg exertion. However, I know of no
study that has examined the recovery of proprioception specifically for clutch
usage following injury. An additional problem in reaching helpful conclusions
from such a study is that there is a variation of clutch pedal resistance
among different vehicles.
While there is no doubt that brake control is of paramount importance,
clutch control should not be underestimated as a component of safe driving.
Therefore, for patients who have had an injury to the left ankle and who drive
an automobile with a manual transmission, I would recommend that a safe return
to driving must await the regaining of appropriate proprioceptive control.
We thank Mr. Carmont for his feedback regarding our article. We agree with
his assessment of the potential problems with use of a clutch by a patient
with an ankle fracture on the left side. Because there are so many variables
associated with the safe operation of a car, we chose the one variable, brake
function, that is affected by ankle surgery on the right side in order to
limit these other variables. It is true that some people may drive an
automobile with an automatic transmission with use of the left foot and not be
affected. We also believe that there may be some proprioceptive feedback loop
that may affect the contralateral lower extremity following injury to one
side.