title: Brake response time before and after total knee arthroplasty: a prospective cohort study.
abstract: BACKGROUND
  Although the numbers of total knee arthroplasty (TKA) are increasing, there is only a small number of studies investigating driving safety after TKA. The parameter 'Brake Response Time (BRT)' is one of the most important criteria for driving safety and was therefore chosen for investigation.The present study was conducted to test the hypotheses that patients with right- or left-sided TKA show a significant increase in BRT from pre-operative (pre-op, 1 day before surgery) to post-operative (post-op, 2 weeks post surgery), and a significant decrease in BRT from post-op to the follow-up investigation (FU, 8 weeks post surgery). Additionally, it was hypothesized that the BRT of patients after TKA is significantly higher than that of healthy controls.
  
  
  METHODS
  31 of 70 consecutive patients (mean age 65.7 +/- 10.2 years) receiving TKA were tested for their BRT pre-op, post-op and at FU. BRT was assessed using a custom-made driving simulator. We used normative BRT data from 31 healthy controls for comparison.
  
  
  RESULTS
  There were no significant increases between pre-op and post-op BRT values for patients who had undergone left- or right-sided TKA. Even the proportion of patients above a BRT threshold of 700 ms was not significantly increased postop. Controls had a BRT which was significantly better than the BRT of patients with right- or left-sided TKA at all three time points.
  
  
  CONCLUSIONS
  The present study showed a small and insignificant postoperative increase in the BRT of patients who had undergone right- or left-sided TKA. Therefore, we believe it is not justified to impair the patient's quality of social and occupational life post-surgery by imposing restrictions on driving motor vehicles beyond an interval of two weeks after surgery.
authors.affiliation: Department of Orthopaedic Surgery, Innsbruck Medical University, Innsbruck, Austria. michael.liebensteiner@i-med.ac.at
authors.forename: Michael C
authors.initials: MC
authors.lastname: Liebensteiner
authors.forename: Michaela
authors.initials: M
authors.lastname: Kern
authors.forename: Christian
authors.initials: C
authors.lastname: Haid
authors.forename: Conrad
authors.initials: C
authors.lastname: Kobel
authors.forename: David
authors.initials: D
authors.lastname: Niederseer
authors.forename: Martin
authors.initials: M
authors.lastname: Krismer
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee; D001334:Automobile Driving; D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000502:physiology* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000503:physiopathology / Q000601:surgery*; D011184:Postoperative Period; D011446:Prospective Studies; D011788:Quality of Life; D011930:Reaction Time / Q000502:physiology*; D020127:Recovery of Function / Q000502:physiology; D012449:Safety; D013997:Time Factors