Effects of continous feromal nerve block on postoperative rehabilitation pain after total knee arthroplasty in obese elderly patients

【Objective】 To evaluate the effects of continuous femoral nerve block on postoperative pain and functional rehabilitation compared with Patient Controlled Epidural Analgesia(PCEA) after total knee arthroplasty(TKA) surgery in elderly obese patients.【Methods】 The sixty elderly obese patients(ASAⅠ～Ⅲ,BMI30 kg/m2) undergoing unilateral TKA surgery were randomly divided into two groups: Group FA and Group EA.All of them received combined spinal-epidural anesthesia(CSEA).In Group FA before initiating CSEA,the femoral nerve block catheters were inserted by nerve stimulator guidance and fixed appropriately,and then the catheter were connected with analgesia pumps postoperatively for pain relief and functional rehabilitation via continuously infusing 0.18% Ropivacaine(bolus injection 15 mL,background infusion 5 mL/h,locking time 30 min,PCA 5 mL).The PCEA with 0.18% Ropivacaine mixed with morphine(background infusion 5 mL/h,locking time 30 min,PCA 2 mL) was performed in Group EA.All the patients were given postoperative analgesia for 72 h.The VAS pain scores during rest and initiative exercise,Ramessay sedation scores,muscle strength grades and adverse reactions were recorded at postoperative 2 h,6 h,24 h,48 h and 72 h respectively.【Results】 There were no difference in the VAS scores during rest and initiative exercise at any time points and the satisfactory of sedation degree between two groups.The muscle strength grades at postoperative 24 h and 48 h in Group FA were significantly higher than that in Group EA(P 0.05).Compared with Group EA,a significantly lower incidence of adverse reactions in Group FA was observed(10% Vs 66.7%,P 0.01).【Conclusion】 As far as the continuous femoral nerve block is concerned,it can provide not only better pain relief,but slight impact on muscle strength of lower extremity and fewer side effects.Therefore,the continuous peripheral femoral nerve block is an ideal method for postoperative analgesia and functional rehabilitation for elderly obese patients after TKA surgery.