Measurement of brake response time after right anterior cruciate ligament reconstruction.

Abstract

Recommendations on safe driving after anterior cruciate ligament (ACL) reconstruction have been largely intuitive. We studied brake response time in patients who participated in outpatient rehabilitation after right ACL reconstruction. Prospective, repeated measures design comparing 14 patients post-ACL reconstruction with 21 subjects with normal knees. The following measures were assessed every 2 weeks for 10 weeks: brake response time, 6-meter walk time, knee range of motion, pain, and joint effusion. Statistical testing used analysis of covariance with repeated measures. Significant variables were analyzed separately and post hoc tests conducted using the least squares differences method. Both groups were compared with published norms from the American Automobile Association. No significant gender differences across main effects were detected. Brake response times for men improved significantly after week 6 (p < .05) and week 10 (p < .01). Brake response times for women in the ACL treatment group matched controls at 6 weeks. Six-meter walk times for control subjects were faster than those for the ACL group preoperatively (2.6 sec vs 5.5 sec), but equalized by week 6. After right ACL reconstruction, brake reaction times of rehabilitated men and women matched those of established controls after 4 to 6 weeks. Measuring brake response times during rehabilitation may ensure that individual patients return to driving in a safe and timely manner.