Randomization and blinding
acute pain
Randomization tables generated by computers randomly assigned patients to three groups (n = 32) to receive 30 mL of plain ropivacaine 0.375% plus 0.25 μg/kg dexmedetomidine (DGroup work was hidden in sealed, numbered, opaque envelopes until the day of surgery. The anesthesiologist’s assistant opened each bag and prepared appropriate study medication. This anesthesiologist is no longer involved in research or patient care. Anesthetists who performed postoperative patient assessments, surgeons, physical therapists, acute pain nurses, and researchers were blinded to treatment group assignment.