An alternative to improve the quality of postoperative analgesia is to use various perineural adjuvants applicable to peripheral nerve block along with local anesthetics to increase the analgesic effect. Dexamethasone is a strong and long-acting corticosteroid, which reduces postoperative nausea and vomiting and increases the duration of nerve blockade. Most of the existing clinical studies compared the analgesic effect with the placebo group after adding an adjuvant in a single shot nerve block, and there were very few cases of comparing the analgesic effect with the placebo group after adding the adjuvant in peripheral nerve block through continuous catheter infusion. Therefore, we designed this study to investigate whether the use of dexamethasone as a peripheral adjuvant for continuous femoral nerve block has a better pain and recovery profile.

Inclusion Criteria:

1. Patients 19 years of age or older who are expected to undergo unilateral hip arthroplasty
2. ASA PS 1-3

Exclusion Criteria:

1. Revision total hip arthroplasty
2. Allergy to drugs used in the study
3. Patients with moderate or more hepatic impairment (AST/ALT is more than 2.5 times the upper limit of normal)
4. Estimated glomerular filtration rate < 30 mL/min/1.73m2
5. Opioid dependence
6. Prolongation of PT and aPTT more than twice the upper limit of normal
7. Pre-existing neurological or anatomical disorders of the lower extremities
8. Serious psychiatric disorders