Several studies exist on patient performance in drive simulators especially around and after surgery. Recommendations concerning the ability to drive preoperatively are based on these studies, which generated their data using drive simulators. However, in all the datasets driving performance remains highly individual. Since a drive simulator is not readily available in normal general practitioner surgeries it would be helpful to have convenient clinical tests to evaluate a patients individual ability to perform an emergency stop. This study aims at evaluating different possibilities how such performance might be predicted. Patients with knee osteoarthritis and patients who have received total knee arthroplasty are tested clinically and their results are compared with the gold standard experiment - a drive simulator.

Inclusion Criteria:

• 18-85 y
• valid driving license
• male and female
• right or left knee Osteoarthritis, Total knee arthroplasty right or left knee
• capability to walk with or without a walking stick

Exclusion Criteria:

• myocardial infarction/Apoplexia < 6 months
• Total knee arthroplasty <5 weeks
• New York Heart Association 3/4
• lacking drivers' license
• peripheric sensomotor deficit <3/5 British Medical Research Council
• new fracture of the lower extremity or spine
• systemic or metastasised Cancer
• drug intake with centrally acting substances known to affect reaction time (Opioids, e.g. Tramadol, oxycodone, morphine, Tilidin)