Inclusion Criteria:  Patients aged between 18 and 65years, scheduled to undergo total knee arthroplasty with an ASA score of 1 to 3 will be included in the study.  Exclusion Criteria:  Patients who will refuse enrollment or later request removal from the study, those who are unable to give informed consent and patients with contraindications for regional anesthesia like known allergy to local anesthetics, bleeding diathesis, use of anticoagulants or corticosteroids, inability to operate patient controlled analgesia (PCA) system, psychiatric disorders or use of psychiatric medications and known allergy to TDB patch.