Opioid Induced Gait Ataxia

This study aims at measuring gait ataxia associated with opioid intake. Patients with knee OA and age matched healthy volunteers will be recruited and are required to meet for 3 all-day assessments. Measurements of gait ataxia (gait variability) will be recorded in the gait laboratory before and every hour for 6 hours after intake of two different kinds of opioids or placebo. The order of opioid/placebo is randomised. Further, the autonomous regulation of pulse and blood pressure is assessed every hour together with self-reported pain and dizziness, and a blood sample to estimate plasma concentrations of the active opioid.