Objective:To evaluate the efficacy of ultrasound-guided adductor canal approach to nerve block using one-puncture four-point technique for analgesia after total knee arthroplasty (TKA).Methods:Sixty patients of both sexes, aged 65-80 yr, with body mass index of 18-27 kg/m 2, of American Society of Anesthesiologists physical status Ⅱor Ⅲ, scheduled for elective unilateral TKA under general anesthesia, were enrolled in this study.Peripheral nerve block was performed for postoperative analgesia under ultrasound guidance.All the patients were allocated into 2 groups ( n=30 each) using a random number table method: adductor canal block combined with posterior approach to sciatic nerve block group (group ASB) and adductor canal approach to nerve block using one-puncture four-point technique including sciatic nerve, medial vastus muscle nerve, saphenous nerve, anterior femoral cutaneous nerve at adductor canal level group (group ANSB). When visual analogue scale score ≥4 during postoperative movement, ketorolac tromethamine 0.6 mg/kg was intravenously injected as rescue analgesic. The muscle strength of quadriceps on the affected side, range of knee joint motion and rate of the ability to walk for 10 m using the walker were recorded at 2, 8, 24 and 48 h after surgery.The consumption of analgesics for rescue analgesia, manipulation completion time, length of hospital stay and patients′ satisfaction score were recorded within 48 h after surgery. Results:Compared with group ASB, the consumption of ketorolac tromethamine was significantly reduced, manipulation completion time and length of hospital stay were shortened, patients′ satisfaction scores were increased, and the range of knee joint motion and rate of the ability to walk for 10 m using the walker were increased at 2, 8, 24 and 48 h after surgery in group ANSB ( P<0.05). There was no significant difference in muscle strength of quadriceps between two groups ( P>0.05). Conclusion:Ultrasound-guided adductor canal approach to nerve block using one-puncture four-point technique provides better efficacy than adductor canal block combined with posterior approach to sciatic nerve block when used for analgesia after TKA.