[Assessment for pain control efficiency of ultrasound guided adductor canal block in total knee arthroplasty: a report of 28 continuous cases].

Objective: To assess the pain control efficiency of continuous adductor canal block in total knee arthroplasty. Methods: From October to December 2015, patients with severe knee osteoarthritis undergoing primary unilateral TKA were observed clinically.All of the patients received ultrasound-guided continuous adductor canal block after surgery.NPRS Pain score in rest and activity at 2, 6, 12, 24, 48 h after surgery were collected, preoperative and postoperative quadriceps strength at 24, 48 h were analyzed. Opioids consumption and anesthesia related adverse effects were also recorded. Results: All of the patients were enrolled. Rest pain control was fairly good(1.8±1.5), (2.4±1.5), (2.7±1.3), (2.7±1.7), (2.3±1.4) score, but the patients were not satisfied with activity pain control(3.1±2.1), (3.1±2.1), (4.2±2.2), (4.7±2.5), (6.2±2.4) score. There were statistically differences comparing the NPRS in rest pain with the score in activity, except for the results between each other at 6 hours (P=0.252>0.05)after surgery.The results showed no significant differences comparing quadriceps strengthpreoperatively with 24, 48 h postoperatively by repeated measurements variance analysis.Eight patients acquired additional use of dolantin once (100 mg/per time) within 24 h and among them three patients acquired once dolantin during 24 to 48 h. Eleven patients complained nausea postoperatively, one reported vomiting and one experienced xerostomia. Conclusion: Ultrasound-guided continuous adductor canal block can reduce resting pain after TKA, but has a limited effect in activity pain control.Quadriceps strength had been spared after ACB, which might performearly benefits in rehabilitation. ACB-related complications need further observation to be defined.