BACKGROUNDThere are several methods for postoperative analgesia for knee surgery. The commonly utilized method is multimodal analgesia based on continuous femoral nerve block. The aim of this study was to investigate the application of continuous adductor canal block for analgesia after total knee replacement and compare this method with continuous femoral nerve block.

METHODSSixty patients scheduled for total knee replacement from June 2013 to March 2014 were randomly divided into a femoral group and an adductor group. Catheters were placed under the guidance of nerve stimulation in the femoral group and under the guidance of ultrasound in the adductor group. Operations were performed under combined spinal and epidural anesthesia. After the operations, 0.2% ropivacaine was given at a speed of 5 ml/h through catheters in all patients. Visual analogue scale (VAS) pain scores at rest and while moving were noted at 4, 24, and 48 hours after the operation, and quadriceps strength was also assessed at these time-points. Secondary parameters such as doses of complementary analgesics and side effects were also recorded.

RESULTSThere were no significant differences between the groups in VAS pain scores at rest or while moving, at 4, 24, or 48 hours after the operation (P > 0.05). At these time-points, mean quadriceps strengths in the adductor group were 3.0 (2.75-3.0), 3.0 (3.0-4.0), and 4.0 (3.0-4.0), respectively, all of which were significantly stronger than the corresponding means in the femoral group, which were 2.0 (2.0-3.0), 2.0 (2.0-3.0), and 3.0 (2.0-4.0), respectively (P < 0.05). There were no significant differences between the groups in doses of complementary analgesics or side effects (P > 0.05). X-ray images of some patients showed that local anesthetic administered into the adductor canal could diffuse upward and reach the femoral triangle.

CONCLUSIONSContinuous adductor canal block with 0.2% ropivacaine could be used effectively for analgesia after total knee replacement. Compared with continuous femoral nerve block, this analgesic method has similar analgesic effects and is associated with less weakness of quadriceps muscle.

Aged ; Amides ; therapeutic use ; Analgesia ; methods ; Arthroplasty, Replacement, Knee ; methods ; Female ; Femoral Nerve ; drug effects ; Humans ; Male ; Middle Aged ; Nerve Block ; methods ; Ultrasonography ; methods

The effects of a non-selective inhibitor of cyclo-oxygenase (COX) indomethacin, and exogenous prostaglandin E(2) (PGE(2)) on A(delta) units and C units in the saphenous nerve of diabetic hyperalgesic rats were studied. The results showed that the conduction velocity of A(delta) units and C units and their mechanical threshold in diabetic hyperalgesic rats were obviously decreased, and a small number of A(delta) units (4/24) and C units (2/18) produced increased spontaneous activities. Intraperitoneal injection of indomethacin in diabetic hyperalgesic rats significantly relieved mechanical hyperalgesia, and resulted in a decrease in spontaneous afferent activities of the A(delta) units and C units. Subcutaneous injection of exogenous PGE(2) into the diabetic hyperalgesic and control rats produced a significant decrease in mechanical threshold of the A(delta) units and C units, and elicited discharge from 3 A(delta) units (3/24) and 1 C unit (1/18) in diabetic hyperalgesic rats and from 2 A(delta) units (2/13) in control rats. The present data suggest that the synthesis and release of PGs are increased in diabetic neuropathy, PGs can sensitize and /or activate A(delta) units and C units and elicit hyperalgesia and allodynia in diabetic rats.
Afferent Pathways ; drug effects ; physiopathology ; Animals ; Diabetes Mellitus, Experimental ; physiopathology ; Femoral Nerve ; drug effects ; physiopathology ; Hyperalgesia ; physiopathology ; Indomethacin ; pharmacology ; Male ; Pain Threshold ; drug effects ; Prostaglandin Antagonists ; pharmacology ; Rats ; Rats, Sprague-Dawley

PURPOSE: Total knee replacement is one of the most painful orthopedic procedures, and effective pain relief is essential for early mobility and discharge from hospital. The aim of this study was to evaluate whether addition of single-injection femoral nerve block to epidural analgesia would provide better postoperative pain control, compared to epidural analgesia alone, after total knee replacement. MATERIALS AND METHODS: Thirty-eight patients received a single-injection femoral nerve block with 0.25% levobupivacaine (30 mL) combined with epidural analgesia (femoral nerve block group) and 40 patients received epidural analgesia alone (control group). Pain intensity and volume of patient-controlled epidural analgesia medication and rescue analgesic requirements were measured in the first 48 hours after surgery at three time periods; 0-6 hours, 6-24 hours, and 24-48 hours. Also, side effects such as nausea, vomiting, and pruritus were evaluated. RESULTS: Median visual analog scale at rest and movement was significantly lower until 48 hours in the femoral nerve block group. Patient-controlled epidural analgesia volume was significantly lower throughout the study period, however, rescue analgesia requirements were significantly lower only up to 6 hours in the femoral nerve block group. The incidences of nausea and vomiting and rescue antiemetic requirement were significantly lower in the femoral nerve block group up to 6 hours. CONCLUSION: The combination of femoral nerve block with epidural analgesia is an effective pain management regimen in patients undergoing unilateral total knee replacement.
Aged ; Analgesia, Epidural/*methods ; Analgesia, Patient-Controlled/*methods ; Anesthetics, Local/administration & dosage/therapeutic use ; Arthroplasty, Replacement, Knee/*methods ; Bupivacaine/administration & dosage/analogs & derivatives/therapeutic use ; Female ; Femoral Nerve/*drug effects ; Humans ; Injections ; Male ; Middle Aged ; Nerve Block/*methods

INTRODUCTION: Adductor canal block (ACB) is hypothesised to provide superior analgesia to femoral nerve block (FNB) for total knee arthroplasty (TKA) while preserving quadriceps strength. METHODS: 30 patients undergoing TKA were randomised to receive either ACB or FNB. Baseline tests of quadriceps strength were performed. Ultrasound-guided blocks with 30 mL of 0.5% ropivacaine were administered before induction of general anaesthesia. Patient-controlled analgesia (morphine) was prescribed for postoperative analgesia. The primary outcome of this prospective, double-blinded, randomised controlled trial was morphine consumption (mean ± standard deviation) in the first 24 hours. Secondary outcomes were pain scores using a numeric rating scale (median and interquartile range [IQR]), quadriceps strength (% of baseline) and functional outcomes at 24 hours and 48 hours postoperatively. RESULTS: There was no statistically significant difference in morphine consumption at 24 hours between the ACB and FNB groups (21 ± 11 mg vs. 20 ± 12 mg; p = 0.85). No statistically significant differences were observed between the ACB and FNB groups in pain scores at 24 hours (at rest: 0 [IQR 0-2] vs. 0 [IQR 0-2]; on movement: 5 [IQR 4-8] vs. 5 [IQR 3-8]) and quadriceps strength (24 hours: 28.8% ± 26.1% vs. 26.8% ± 19.6% of baseline; 48 hours: 31.5 ± 23.1% vs. 33.7% ± 20.1% of baseline). There were also no statistically significant differences in functional outcomes and length of stay. CONCLUSION We found no statistically significant differences in analgesic effects, quadriceps strength or functional recovery postoperatively between ACB and FNB.
Aged ; Aged, 80 and over ; Analgesia, Patient-Controlled ; methods ; Analgesics, Opioid ; therapeutic use ; Anesthetics, Local ; administration & dosage ; Arthroplasty, Replacement, Knee ; Double-Blind Method ; Female ; Femoral Nerve ; Humans ; Male ; Middle Aged ; Morphine ; therapeutic use ; Nerve Block ; methods ; Pain Management ; methods ; Pain Measurement ; Pain, Postoperative ; drug therapy ; Prospective Studies ; Quadriceps Muscle ; drug effects ; Treatment Outcome ; Ultrasonography