Driving reaction time before and after anterior cruciate ligament reconstruction.

Driving reaction time was studied in 73 patients under anterior cruciate ligament (ACL) reconstruction using a computer-linked automobile simulator. Each patient was tested pre-operatively and 2, 4, 6 and 8 weeks after surgery. Stepping and standing tests were studied at each time point. Twenty-five normal subjects were also tested as controls. Pre-operative test results did not differ significantly between groups on any of the tests. Post-operatively it took 6 weeks for driving reaction time of the right ACL group to be equivalent to that of the controls, compared to 2 weeks in the left ACL group. There was a strong correlation between the stepping and standing tests and the driving reaction time; this made them good clinical tests to monitor patients' progress and to suggest the appropriate time to resume driving.