Comparison of continuous femoral nerve block (CFNB/SA) and continuous femoral nerve block with mini-dose spinal morphine (CFNB/SAMO) for postoperative analgesia after total knee arthroplasty (TKA): a randomized controlled study

Abstract

BackgroundUnsatisfactory analgesia for major knee surgery with femoral nerve block (FNB) alone was reported and the additional benefit of sciatic block to continuous femoral nerve block (CFNB) was not conclusive. The aim of the present study was to find the benefit of the additional mini-dose spinal morphine (0.035 mg) to CFNB for postoperative pain control and to compare their associated side effects after total knee arthroplasty (TKA).MethodsAfter written informed consent and with Institutional Ethics Committee approval, 68 American Society of Anesthesiologists (ASA) Physical Status I-III patients scheduled for elective unilateral TKA under spinal anesthesia (SA) were included in the present prospective, randomized controlled study. The patients were allocated into two groups. CFNB was placed in all patients by the inguinal paravascular approach with 20 ml of 0.25 % levobupivacaine. Group I (named CFNB/SA group), SA was administered with 2.8 ml levobupivacaine and Group II (named CFNB/SAMO group), SA with 2.8 ml levobupivacaine plus morphine 0.035 mg. At Post Anesthesia Care Unit (PACU), pain and other adverse effects were recorded. Pain was assessed by visual analog scale (VAS) 0-10. Tramadol 50 mg intravenous (IV) was given if the VAS > 4. In the ward, all patients were maintained by continuous femoral infusion of 0.125 % levobupivacaine rate 7 ml/hr and then reduced to 5 ml/hr if VAS ≤3.ResultsPatient’s demographics data in each group were not different. At post-operative (PO) 12-24 h, the VAS scores were significantly lesser in the CFNB/SAMO group. Cumulative tramadol IV requirement for PO48h were also significantly lesser in the CFNB/SAMO group. Nausea, vomiting and numbness were significantly greater in the CFNB/SAMO group during early postoperative period (PO1-6 h).ConclusionThough in some patients CFNB was inadequate, a mini-dose of intrathecal morphine (0.035 mg) in addition to CFNB was found to be effective with minimal side effects.Trial registrationThai Clinical Trial Registry (identifier: TCTR20150609003, date of registration: 6 June 2015).

Comparison of Continuous Epidural Analgesia and Continuous Femoral Analgesia on Postoperative Pain and Knee Rehabilitation after Total Knee Arthroplasty

“…Mahoney and colleagues have reported that epidural analgesia had improved pain control and early rehabilitation was associated with a reduction of approximately 2 days in the length of hospital stay but the high incidence of side effects should not be ignored [17]. Many other studies have demonstrated adequate analgesia, accelerated rehabilitation, minimal side effects and short hospital stay after single dose femoral block or continuous infusion [3,6,18,19,20]. In our study, the discharge times from the hospital were similar between the two groups.…”

Comparison of Ultrasound-Guided Femoral Nerve Block with Combined Spinal Epidural Anesthesia in Total Knee Arthroplasty

“…Other studies support this data (17,18). Sundarathiti et al reported that FNB was similar to epidural anesthesia for postoperative VAS values but postoperative complications were higher than with epidural anesthesia (19). Furthermore, in some studies there was no difference in terms of postoperative VAS scores between continuous FNB and single shot FNB (20,21).…”

Preventive Analgesia by Local Anesthetics

“…20 When compared to an epidural infusion, the epidural provided superior pain control, as might be predicted given that a femoral block does not cover the entire surgical area. 21 However, if a sciatic nerve block was performed in addition to a CFNB and compared to an epidural, pain scores and/or opioid use were unchanged, 22 and as predicted a single-shot or continuous sciatic nerve block administered in addition to a CFNB was superior to a CFNB or CLPB alone. 22,23–25 …”