Reaction Time and Brake Pedal Depression Following Arthroscopic Hip Surgery: A Prospective Case-Control Study.

Purpose: The purpose of this study was to determine whether patients diagnosed with femoroacetabular impingement (FAI) syndrome have prolonged braking times compared with age- and gender-matched controls and how long after surgery braking times return to preoperative baseline.

Methods: Fifty-nine patients undergoing arthroscopic hip surgery for FAI and 59 age- and gender-matched controls without FAI were enrolled in a prospective comparative study between September 2015 and October 2016. Total brake reaction time (BRT) and brake pedal depression (BPD) were measured for study patients preoperatively, and at 2, 4, and 6 weeks postoperatively. BRT and BPD were compared between study and control patients and between preoperative and postoperative time periods, using mixed effects models.

Results: Patients with FAI had significantly prolonged BRT (but not BPD) prior to surgery compared with controls (568 vs 520 msec, P = .002). For study patients undergoing left hip surgery, there was no difference in BRT or BPD between preoperative measurements and any postoperative time point, including the first postoperative appointment at 2 weeks (563 vs 566 msec, P = .89). Patients undergoing right hip surgery had significantly prolonged BRT at 2 weeks postoperatively compared with their preoperative baseline (688 vs 573 msec, P < .001). By 4 weeks postoperatively, study patients undergoing right hip surgery had returned to their preoperative baseline (573 vs 594 msec, P = .28). No significant effect was seen based on visual analog scale pain score, opiate usage, or patient-reported outcome scores.

Conclusions: Patients undergoing arthroscopic surgery of the right hip show significantly prolonged BRT until 4 weeks after surgery, while patients undergoing surgery of the left hip show no postoperative impairment in either BRT or BPD. The clinical relevance of this measured difference (an increase in 10 feet of stopping distance at 60 miles per hour) remains an open question.

Level Of Evidence: Level II, diagnostic, prospective.