Braking Reaction Time After Right-Knee Anterior Cruciate Ligament Reconstruction: A Comparison of 3 Grafts

Abstract

To determine when patients recover the ability to safely operate the brakes of an automobile after a right-knee anterior cruciate ligament reconstruction (ACLR). A computerized driving simulator was used to determine braking ability after an isolated right-knee ACLR. Thirty healthy volunteers were tested at 1 visit to determine normal mean values, and 27 treatment subjects were tested at 1week, 3weeks, and 6weeks after ACLR. Nine study subjects were treated with a patella tendon (BPTB) autograft, 9 were treated with a hamstring (HS) autograft, and 9 were treated with a tibialis anterior (TA) allograft. The driving simulator collected data on brake reaction time (BRT), brake travel time (BTT), and total brake time (TBT) at each visit. The control group generated a BRT of 725milliseconds, BTT of 2.87seconds, and TBT of 3.59seconds. At week 1, all treatment patients had significant differences compared with controls for BRT, BTT, and TBT, except the BTT of the HS group. At week 3, all measures for the allograft group and the BRT for both autograft groups were no longer significantly different compared with controls, but significant differences were found for TBT in the HS and BPTB groups (P= .03, P= .01). At week 6, BRT, BTT, and TBT were no longer significantly different for either the HS group or BPTB group. Patients who underwent a right-knee ACLR with a TA allograft regained normal braking times by week 3 postoperatively. In contrast, those treated with a BPTB or HS autograft demonstrated significantly delayed braking times at 3weeks but returned to normal braking ability by week 6. Those treated with an autograft had an earlier return of normalized BRT than BTT. Level III, case-control series.