Inclusion Criteria:  American Society of Anesthesiologist class ( ASA) I - III BMI 18-35 kg/m2 Scheduled for primary unilateral TKR  Exclusion Criteria:  Known allergy to local anesthetics Contraindication to adductor canal block e.g. infection at the site of injection Contraindication to spinal anesthesia e.g. coagulopathy. Patients with pre-existing motor or sensory deficits in lower extremities. Patients who are morbidly obese (BMI≥35) because ultrasound-guided regional anesthesia could be technically difficult. Bilateral or revision total knee replacement Insulin or noninsulin-dependent diabetes mellitus. systemic corticosteroid use within 30-days of surgery