Comparison Of Proximal Plus Distal Versus Middle Segment Adductor Canal Blocks For Analgesia After Total Knee Arthroplasty

Objective:To evaluate the analgesic effect of ultrasound-guided adductor canal block(ACB)in total knee arthroplasty(TKA)and the difference of two different nerve block methods in postoperative analgesia.Methods:Between February 2018 and December 2018,60 patients underwent primary unilateral total knee arthroplasty under spinal anesthesia.30 patients received proximal plus distal adductor canal block,and 30 patients received middle segment adductor canal block for postoperative analgesia.After the completion of spinal anesthesia,the patients were randomized to receive either proximal plus distal adductor canal block(PD group)or middle segment adductor canal block(M group).The block was performed according to the grouping.In PD group,0.5% ropivacaine10 ml was administered at the proximal and distal ends of adductor canal,respectively.And 0.5% ropivacaine 20 ml was administered to the middle segment of adductor canal in the M group.Both groups began to use patient-controlled analgesia pump to assist postoperative analgesia at the completion of the operation.The block operation time,operative time and tourniquet use time were recorded during the operation.All the patients were followed up for numerical rating scale(NRS)scores at rest at postoperative 4 h,6 h,8 h,12 h,24 h and 48 h,respectively.And NRS scores at45°flexion of the knee at postoperative 24 h and 48 h.Muscle strength of quadriceps femoris,drug dosage of patient-controlled analgesia pump,incidence of rescue analgesia,side effects of opioid drugs such as nausea and vomiting,and patient satisfaction.Results:There was no significant difference in nerve block operation time,operative time and tourniquet use time between the two groups(p>0.05),and there was nosignificant difference in resting NRS scores at postoperative 4 h,8 h,24 h and 48 h between the two groups(p>0.05).The resting NRS score at postoperative 6h,12 h in PD group was significantly lower than that in M group(p<0.05).Drug dosage of patient-controlled analgesia pump in PD group was lower than that in M group within postoperative 24 hours,and the incidence of need for rescue analgesia in PD group was significantly lower than that in M group(p<0.05).There was no significant difference in NRS score and muscle strength of quadriceps femori at postoperative 24 h and 48 h.And there was no significant difference in the incidence of adverse reactions such as nausea,vomiting and dizziness after operation and patients' satisfaction(p>0.05).Conclusion:Ultrasound-guided adductor canal block can provide postoperative analgesia for patients undergoing total knee arthroplasty.The analgesic effect of proximal plus distal adductor canal block was better than that of middle segment adductor canal block after operation.