Effect of Perineural or Intravenous Betamethasone on Femoral Nerve Block Outcomes in Knee Arthroplasty: A Randomized, Controlled Study

OBJECTIVES

Despite the use of multimodal analgesia, patients undergoing knee arthroplasty still encounter residual moderate pain. The addition of betamethasone to local anesthetic has been shown to improve postoperative pain. However, it remains uncertain whether the positive effects of perineural or intravenous administration of betamethasone on analgesia outcomes lead to better early mobility and postoperative recovery.

METHODS

Between June 2022 and February 2023, a total of 159 patients who were undergoing knee arthroplasty were included in this study. These patients were allocated randomly into three groups: (i) the NS group, received ropivacaine 0.375% and intravenous 3mL 0.9% normal saline; (ii) the PNB group, received ropivacaine 0.375% plus perineural betamethasone (12mg) 3mL and intravenous 3mL 0.9% normal saline; and (iii) the IVB group, received ropivacaine 0.375% and intravenous betamethasone (12mg) 3mL.

RESULTS

Both perineural and intravenous administration of betamethasone led to improved median (IQR) numeric rating scale (NRS) scores on the 6-meter walk test, with a score of 1.0 (1.0-2.0) for both groups, compared with 2.0 (1.0-2.0) for the NS group (p = 0.003). Compared to the NS group, both the PNB and IVB groups showed significant reductions in NRS scores at 24 and 36 h after surgery, along with a significant increase in ROM at 24, 36, and 48 h post-operation. Additionally, it exhibited lower levels of cytokine IL-1β and TNF-α in fluid samples, as well as lower level of HS-CRP in blood samples in the PNB and IVB groups compared to the NS group.

CONCLUSION

The administration of perineural and intravenous betamethasone demonstrated an enhanced analgesic effect following knee arthroplasty. Furthermore, it was associated with reduced levels of IL-1β, TNF-α, and HS-CRP, as well as enhanced knee ROM, which is conducive to early ambulation and postoperative rehabilitation after knee arthroplasty.

Perineural Dexmedetomidine Reduces the Median Effective Concentration of Ropivacaine for Adductor Canal Block

BACKGROUND Multimodal analgesic regimens are well known as the best option for total knee arthroplasty. They include the adductor canal block, combined with local infiltration analgesia and a block of the interspace between the popliteal artery and the capsule of the posterior knee. However, these analgesic techniques all require a large amount of local anesthetics. In this study, we explored whether the quantity of local anesthetics could be decreased by using dexmedetomidine for the adductor canal block. MATERIAL AND METHODS Fifty-four patients scheduled for unilateral, primary total knee arthroplasty were allocated into 2 groups: the ropivacaine group (group R) and the dexmedetomidine group (group RD). Ropivacaine 0.5% was chosen as the initial concentration, and the concentration was decreased or increased according to the response of the previous participant. Based on Dixon's up-and-down method, the median effective concentration was calculated. RESULTS The quadriceps strength was similar between the 2 groups, both at 30 min after adductor canal block and during recovery from general anesthesia in the Postanesthesia Care Unit. None of the patients in this study exhibited bradycardia or hypotension. The median effective concentration of ropivacaine for adductor canal block was 0.29% (95% confidence interval [CI], 0.28-0.31%) in group RD, which was lower than that in group R (0.38% [95% CI, 0.36-0.41%]). CONCLUSIONS This study found perineural dexmedetomidine 1 μg/kg could reduce the median effective concentration of ropivacaine for the adductor canal block.

Was femoral nerve block effective for pain control of medial opening-wedge high tibial osteotomy?: A single blinded randomized controlled study

BACKGROUND AND PURPOSE

Medial compartment femoro-tibial osteoarthritis (OA) is a common disease and opening-wedge high tibial osteotomy (OWHTO) is the common surgical procedure carried out for these patients. While most researchers are focusing on the surgical techniques during operation, the aim of this study is to evaluate the pain control effect of femoral nerve block (FNB) for OWHTO patients.

METHODS

In this prospective, single-center, randomized controlled trial (RCT) study, 41 patients were operated on by OWHTO for OA during 2017 to 2018. Twenty of them (group A) accepted epidural anesthesia with FNB and 21 patients (group B) only had their single epidural anesthesia. All blocks were successful and all the 41 patients recruited were included in the analysis and there was no loss to follow-up or withdrawal. Systematic records of visual analog scores (VAS), quadriceps strength, mean number of times of patient-controlled intravenous analgesia (PCIA), using of additional opioids or nonsteroidal anti-inflammatory drugs (NSAIDs), and complications were done after hospitalization. The Student t test and Chi-Squared test was used and all P values ≤.05 were considered statistically significant.

RESULTS

VAS scores at rest (3.48 ± 1.0 vs 4.68 ± 1.1) and on movemment (4.51 ± 0.6 vs 4.97 ± 0.8) decreased more in group A than group B with significance at follow-up of 12 hours. The quadriceps strength, consumption of additional opioids or NSAID injections and mean number of times that the patients pushed the PCIA button didnot differ significantly within each group.

CONCLUSION

This RCT study shows that FNB in patients undergoing OWHTO for unicompartmental osteoarthritis of the knee could result in significant reduction in VAS scores at 12 hours postoperatively.Research registry, Researchregistry4792. Registered April 7, 2019 - Retrospectively registered, http://www.researchregistry.com.

Immunohistochemical Femoral Nerve Study Following Bisphosphonates Administration

Background and objectives: Bisphosphonates represent selective inhibitors of excess osteoblastic bone resorption that characterizes all osteopathies, targeting osteoclasts and their precursors. Their long-term administration in postmenopausal women suffering from osteoporosis has resulted in neural adverse effects. The current study focuses on the research of possible alterations in the femoral nerve, caused by bisphosphonates. We hypothesized that bisphosphonates, taken orally (per os), may produce degenerative changes to the femoral nerve, affecting lower-limb posture and walking neuronal commands. Materials and Methods: In order to support our hypothesis, femoral nerve specimens were extracted from ten female 12-month-old Wistar rats given 0.05 milligrams (mg) per kilogram (kg) of body weight (b.w.) per week alendronate per os for 13 weeks and from ten female 12-month-old Wistar rats given normal saline that were used as a control group. Specimens were studied using immunohistochemistry for selected antibodies NeuN (Neuronal Nuclear Protein), a protein located within mature, postmitotic neural nucleus, and cytosol and Sox10 (Sex-determining Region Y (SRY) - High-Motility Group (HMG) - box 10). The latter marker is fundamental for myelination of peripheral nerves. Obtained slides were examined under a light microscope. Results: Samples extracted from rats given alendronate were more Sox10 positive compared to samples of the control group, where the marker's expression was not so intense. Both groups were equally NeuN positive. Our results are in agreement with previous studies conducted under a transmission electron microscope. Conclusions: The suggested pathophysiological mechanism linked to histological alterations described above is possibly related to toxic drug effects on Schwann and neuronal cells. Our hypothesis enhances the existing scientific evidence of degenerative changes present on femoral nerve following bisphosphonates administration, indicating a possible relationship between alendronate use and neuronal function.

Continuous femoral nerve block is more effective than continuous adductor canal block for treating pain after total knee arthroplasty: A randomized, double-blind, controlled trial

OBJECTIVES

Previous studies comparing adductor canal block (ACB) with femoral nerve block (FNB) are inconclusive with regard to patient-controlled analgesia (PCA) induced by opioids. Moreover, some postoperative pain severity results differ between previous randomized controlled trials (RCTs). The primary aim of the current study was to compare total intravenous morphine consumption administered via PCA during the first postoperative day in continuous FNB and ACB groups after total knee arthroplasty (TKA). Secondary aims included evaluation of postoperative pain via a visual analog scale, degree of knee extension, quadriceps muscle strength, and ability to sit, stand upright, and walk.

METHODS

The study was a RCT. Inclusion criteria were presence of gonarthrosis, age >18 and <75 years, and scheduled for TKA under single-shot spinal anesthesia.

RESULTS

A number of morphine uses was lower in the FNB group than in the ACB group (14, range 12-15 vs 20, range 18-22; P = .0001), and they perceived less severe pain at the 8th (P = .00003) and 24th hours. However, ACB was significantly superior with regard to most of the other parameters pertaining to mobility, including muscle strength at the 8th and 24th hours, degree of knee extension at the 8th hour, sitting at the 8th hour, standing upright at the 24th hour, and walking at the 24th and 48th hours.

DISCUSSION

FNB was associated with the perception of less severe pain after TKAs. However, ACB was associated with earlier mobility rehabilitation.

A Comparison of Pain Management Protocols Following Total Knee Arthroplasty: Femoral Nerve Block versus Periarticular Injection of Liposomal Bupivacaine with an Adductor Canal Block

BACKGROUND

Total knee arthroplasty (TKA) results in significant postoperative pain and a demanding postoperative path for recovery. This study was conducted to determine whether a femoral nerve block (FNB) or a periarticular injection of liposomal bupivacaine with an adductor canal block (LB+ACB) is superior for pain management.

MATERIALS AND METHODS

A total of 557 consecutive primary TKA cases performed at a single hospital between 2010-2014 were retrospectively reviewed. After enrollment criteria were met, 390 cases remained (FNB=181, LB+ACB=209). Inpatient and post-discharge variables related to pain, narcotic use, healthcare resource utilization, and cost were compared.

RESULTS

There were no significant differences in demographics between the two groups. There was also no significant difference in inpatient postoperative pain between the two groups. The FNB group consumed fewer narcotics overall compared to the LB+ACB group (p<0.001). However, the LB+ACB group experienced fewer opioid-related adverse events (p<0.001). The LB+ACB group had a shorter length of stay (p<.001), fewer readmissions (p=0.017) and reoperations (p=0.025), and lower costs (p<0.001).

DISCUSSION

LB+ACB proved to be an equally effective postoperative TKA pain management tool compared to FNB while displaying superiority in other increasingly important areas such as length of stay and cost. The larger amount of narcotic consumption is a concern, however, and there may be a small population of patients for whom LB+ACB is not the best option.

Ultrasound-Guided Continuous Femoral Nerve Block with Dexmedetomidine Combined with Low Concentrations of Ropivacaine for Postoperative Analgesia in Elderly Knee Arthroplasty

OBJECTIVES

This study aims to investigate the clinical effect of dexmedetomidine (DEX) combined with low concentrations of ropivacaine in ultrasound-guided continuous fem-oral nerve block for postoperative analgesia in elderly patients with total knee arthroplasty (TKA).

MATERIALS AND METHODS

Patients were divided into three groups: group C, group D1, and group D2. For postoperative analgesia, patients in group C were given 0.15% ropivacaine, patients in group D1 were given 0.15% ropivacaine + 0.02 μg × kg-1 × h-1 DEX, and patients in group D2 were given 0.15% ropivacaine + 0.05 μg × kg-1 × h-1 DEX. The visual analogue scores in the resting state, active state (AVAS), and passive functional exercise state (PVAS), degree of joint bending, and Ramsay scores were recorded.

RESULTS

The Ramsay scores were significantly higher, AVAS scores were significantly lower, PVAS scores were significantly decreased, the degree of joint bending was significantly higher, and the time to the first postoperative ambulation was shorter in groups D1 and D2 than group C. Furthermore, the time to the first postoperative ambulation was shorter in group D2 than in group D1, patients in groups D1 and D2 were more satisfied than patients in group C, and patients in group D2 were more satisfied than patients in group D1.

CONCLUSION

The protocol of 0.05 μg × kg-1 × h-1 of DEX combined with 0.15% ro-pivacaine in ultrasound-guided continuous femoral nerve block for postoperative analgesia in elderly patients with TKA provides a better analgesic effect than without DEX performance.

X.-Y.Z. and E.-F.Z. have contributed equally to this research.

Pericapsular Nerve Group (PENG) Block for Hip Fracture

Fascia iliaca block or femoral nerve block is used frequently in hip fracture patients because of their opioid-sparing effects and reduction in opioid-related adverse effects. A recent anatomical study on hip innervation led to the identification of relevant landmarks to target the hip articular branches of femoral nerve and accessory obturator nerve. Using this information, we developed a novel ultrasound-guided approach for blockade of these articular branches to the hip, the PENG (PEricapsular Nerve Group) block. In this report, we describe the technique and its application in 5 consecutive patients.

The Prolonged Analgesic Efficacy of an Ultrasound-Guided Single-Shot Adductor Canal Block in Patients Undergoing Total Knee Arthroplasty

In this prospective, randomized, placebo-controlled study, the authors compared the analgesic efficacy of the single-shot adductor canal block (SS-ACB) vs the continuous adductor canal block (C-ACB) with intermittent boluses during the 72-hour postoperative period. Seventy-five patients randomly received the following: a single shot of 20 mL of 0.5% ropivacaine preoperatively followed by intermittent saline boluses at 12 hours and 24 hours postoperatively (SS-ACB group); 20 mL of 0.5% ropivacaine preoperatively and 12 hours and 24 hours postoperatively (C-ACB group); or saline preoperatively and postoperatively (control group). The primary outcome was visual analog scale pain scores with movement on postoperative day 1. The dynamic pain scores of the 2 ACB groups were equivalent and were lower than those of the control group on postoperative day 1. Compared with the control group, the 2 ACB groups were less likely to use opioids on the operative day and the first 2 postoperative days. The patients in the control group and the C-ACB group exhibited less quadriceps muscle strength than those in the SS-ACB group on postoperative day 1. The time required for an SS-ACB was markedly shorter than that required for an indwelling adductor canal catheter. Further, each adductor canal catheter cost $80. Patients who received a single block reported more satisfaction with their pain-relief treatment. Given the similar analgesic effect but better quadriceps muscle strength, easier execution, and higher patient satisfaction, the SS-ACB may be more suitable for total knee arthroplasty patients than the C-ACB. [Orthopedics. 2018; 41(5):e607-e614.].

Postoperative Regional Analgesia Is Effective in Preserving Perforin-Expressing Lymphocytes in Patients After Total Knee Replacement

BACKGROUND Pain and surgical stress cause a pro-inflammatory response followed by downregulation of the immune response, which can increase the incidence of postoperative complications, such as infections or prolonged wound healing. T lymphocytes and natural killer (NK) cells have cytotoxic potential and are crucial components of cellular immunity, which is important for maintenance of immune balance. The aim of this study was to analyze the effects of 3 types of postoperative analgesia on the preservation and cytotoxic potential of T lymphocytes, NK cells, and their subpopulations, as well as NKT cells, in patients after total knee replacement (TKR) to find the most effective analgesic technique for mitigating immune suppression. MATERIAL AND METHODS Forty-eight patients scheduled for TKR were randomly allocated to Group 1 (patients received epidural analgesia), Group 2 (patients received sciatic and femoral nerve block), or Group 3 (patients received multimodal systemic analgesia). Pain intensity was assessed at rest and on movement before, immediately after, and at 24 and 72 h after surgery. Blood samples were collected at the same time points and peripheral blood mononuclear cells were isolated. The frequencies of T lymphocytes, NK cells, and NKT cells, as well as their perforin expression, were simultaneously detected and analyzed by flow cytometry. RESULTS Patients in Group 1 and Group 2 experienced less severe pain than those in Group 3. The frequencies and perforin levels of T lymphocytes, their subsets, and NKT cells were significantly lower in Group 3 than in Group 1 and Group 2. CONCLUSIONS The present study confirmed that regional analgesia is more effective in maintaining cell-mediated immunity and perforin expression in peripheral blood lymphocytes in patients after TKR.

In patients undergoing fast track total knee arthroplasty, addition of buprenorphine to a femoral nerve block has no clinical advantage: A prospective, double-blinded, randomized, placebo controlled trial

BACKGROUND

Several adjuvants have been proposed to prolong the effect of peripheral nerve blocks, one of which is buprenorphine. In this randomized double blinded placebo controlled trial we studied whether the addition of buprenorphine to a femoral nerve block prolongs analgesia in patients undergoing total knee arthroplasty in a fast track surgery protocol.

METHODS

The treatment group (B) was given an ultrasound-guided femoral nerve block with ropivacaine 0.2% and 0.3mg buprenorphine. We choose to use 2 control groups. Group R was given a femoral nerve block with ropivacaine 0.2% only. Group S also received 0.3 mg buprenorphine subcutaneously. Only patients with a successful block were enrolled in the study.

RESULTS

We found no difference in our primary outcome parameter of time to first rescue analgesic. We found lower opioid use and better sleep quality the first postoperative night in patients receiving buprenorphine perineurally or subcutaneously. Buprenorphine did not lead to any significant change in pain or mobilization. We found a high overall incidence of nausea and vomiting.

CONCLUSION

In patients undergoing total knee arthroplasty, in the setting of a fast track surgery protocol, the addition of buprenorphine to a femoral nerve block did not prolong analgesia.

Ultrasound-Guided Femoral Nerve Blockage in A Patellar Dislocation: An Effective Technique for Emergency Physicians

BACKGROUND

Patellar dislocation is an orthopedic emergency and its reduction can be painful. The aim of this case is to show that the ultrasound-guided femoral nerve blockage can be effectively used in the pain management of patellar reduction in the emergency department (ED).

CASE REPORT

A 21-year-old man was admitted to our ED after suffering a fall down a flight of stairs. The initial physical examination and plain radiography showed a patellar dislocation in the right knee. We performed an ultrasound-guided femoral nerve blockage to provide a pain-free and comfortable patellar reduction. To our best knowledge, there is no manuscript except an old case series about use of the ultrasound-guided femoral nerve blockage in the management of patellar reduction in the medical literature. Procedural sedation is the preferred method used for this purpose in ED, but these medications need to be closely monitored because of their potential complications, such as nausea, vomiting, allergic reactions, and respiratory depression. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Ultrasound-guided femoral nerve blockage gave rapid and effective pain control without any complication during the reduction in this patient. Therefore, we suggest this technique be used for pain management during the reduction of a dislocated patella in the ED.

[Comparision for clinical efficiency of continuous adductor canal block and femoral nerve block in total knee arthroplasty]

OBJECTIVE

To compare the pain control efficiency of continuous adductor canal block (ACB) and femoral nerve block (FNB) in total knee arthroplasty.

METHODS

From April to September 2016, patients with severe knee osteoarthritis undergoing primary unilateral total knee arthroplasty (TKA) were prospectively observed, and all the patients were randomized received ultrasound-guided continuous ACB or FNB after surgery. Numeric pain rating scales(NPRS)pain scores in rest and activity 2, 6, 12, 24 and 48 h after surgery were collected, and the preoperative and postoperative quadriceps strength at 24 and 48 h were analyzed. Opioids consumption and anesthesia related adverse effects were also recorded.

RESULTS

In the study, 40 patients were enrolled, with 20 patients in each group, male:female=7:33, the age: (63.8±10.1) years, and the body mass index (BMI): (28.5±3.5) kg/m(2).The general conditions were comparable between the two groups. Though the rest pain 2 h after surgery [ACB=0.0(0,6), FNB=3.0(0,5), P=0.004] and activity pain 12 h post operation [ACB=3.0(3,0), FNB=5.5(0,10), P=0.004] were lower in ACB group compared with FNB group, there was no statistical difference in the other pain checking points between the two groups. The quadriceps strength 24 h and 48 h after surgery were(85.3±27.6) N and (80.0±30.1) N in ACB group, (69.0±29.4) N and (64.4±32.0) N in FNB group, both of them were declined by time. The exact data were higher in ACB group, however, there was no statistical difference between the two group by repeated measurements variance analysis(F=2.703, P=0.108).Four patients in ACB group and five in FNB acquired additional use of dolantin once (100 mg/per time) within 24 h. And among them, three patients acquired once dolantin in ACB, two in FNB, from 24 to 48 h postoperation. There were five patients who suffered nausea postoperation in ACB group, and one who reported xerostomia. Four patients in FNB had nausea with vomiting, and three experienced xerostomia. Deep vein thrombosis appeared in 2 patients in FNB group, but no one in ACB group.

CONCLUSION

Continuous ACB is not superior in pain control after TKA compared with FNB, and the quadriceps strength could be reserved more by this method, which performed early benefits in fast rehabilitation.

[Effect of continuous femoral nerve block combined with periarticular local infiltration analgesia on early operative functional recovery after total knee arthroplasty: a randomized double-blind controlled study]

OBJECTIVE

To investigate the effects of early rehabilitation training after total knee arthroplasty surgery by continuous femoral nerve block (CFNB) with or without periarticular local infiltration analgesia (PLIA).

METHODS

In this randomized, double-blind, controlled study, 100 patients under-going primary unilateral total knee arthroplasty in patients with knee osteoarthritis were enrolled. All the patients received CFNB for postoperative analgesia before combined spinal epidural anesthesia. They were randomly divided into 2 groups (n=50 each): CFNB group, CFNB combined with PLIA group (PLIA group). Group PLIA received periarticular local infiltration analgesia with 20 mL ropivacaine (5 g/L), while the equal volume of normal saline was used instead of ropivacaine in group CFNB. Postoperative pain during rest and passive exercises including front and rear portions of knees, the time of ability to perform an active straight leg raise, the time of ability to reach 90° knee flexion, and preoperative and postoperative hospital for special surgery knee score (HSS) were evaluated.

RESULTS

Compared with group CFNB, the visual analogue scores (VAS) of front of knees at rest time in group PLIA had no significant difference (P>0.05); there were significant differences at 4, 8, 12, 24 h postoperation in portions of knees at rest time (P<0.05); the VAS had significant differences at 24 h in passive exercises of knees (P<0.05); the VAS had significant differences at 12, 24 h in portions of knees at passive exercises of the knees (P<0.05); the time of ability to perform an active straight leg raise had significant differences in the two groups (P<0.05).

CONCLUSION

Compared with CFNB postoperative analgesia alone, CFNB with PLIA could relieve rest pain and pain during passive movement after total knee arthroplasty. CFNB with PLIA could shorten the time to perform an active straight leg raise and the time of ability to reach 90° knee flexion. And so some patients could improve postoperative rehabilitation training.

Effectiveness and safety of continuous ultrasound-guided femoral nerve block versus epidural analgesia after total knee arthroplasty

OBJECTIVES

Total knee arthroplasty is associated with severe postoperative pain. The aim of this study was to compare continuous ultrasound-guided femoral nerve block with continuous epidural analgesia, both with low concentrations of local anaesthetic after total knee arthroplasty.

MATERIAL AND METHODS

A prospective, randomised, unblinded study of 60 patients undergoing total knee replacement, randomised into two groups. A total of 30 patients received continuous epidural block, while the other 30 received continuous ultrasound-guided femoral nerve block, as well as using 0.125% levobupivacaine infusion in both groups. Differences in pain control, undesirable effects, and complications between the two techniques were assessed, as well as the need for opioid rescue and the level of satisfaction with the treatment received during the first 48hours after surgery.

RESULTS

No differences were found in demographic and surgical variables. The quality of analgesia was similar in both groups, although in the first six hours after surgery, patients in the epidural group had less pain both at rest and with movement (P=.007 and P=.011). This difference was not observed at 24hours (P=.084 and P=.942). Pain control at rest in the femoral block group was better at 48hours after surgery than in the epidural group (P=.009). The mean consumption of morphine and level of satisfaction were similar. Epidural analgesia showed the highest rate of side effects (P=.003).

CONCLUSIONS

Continuous ultrasound-guided femoral nerve block provides analgesia and morphine consumption similar to epidural analgesia, with the same level of satisfaction, but with a lower rate of side effects after total knee arthroplasty.

Small Molecule Agonists of Cell Adhesion Molecule L1 Mimic L1 Functions In Vivo

Lack of permissive mechanisms and abundance of inhibitory molecules in the lesioned central nervous system of adult mammals contribute to the failure of functional recovery after injury, leading to severe disabilities in motor functions and pain. Peripheral nerve injury impairs motor, sensory, and autonomic functions, particularly in cases where nerve gaps are large and chronic nerve injury ensues. Previous studies have indicated that the neural cell adhesion molecule L1 constitutes a viable target to promote regeneration after acute injury. We screened libraries of known drugs for small molecule agonists of L1 and evaluated the effect of hit compounds in cell-based assays in vitro and in mice after femoral nerve and spinal cord injuries in vivo. We identified eight small molecule L1 agonists and showed in cell-based assays that they stimulate neuronal survival, neuronal migration, and neurite outgrowth and enhance Schwann cell proliferation and migration and myelination of neurons in an L1-dependent manner. In a femoral nerve injury mouse model, enhanced functional regeneration and remyelination after application of the L1 agonists were observed. In a spinal cord injury mouse model, L1 agonists improved recovery of motor functions, being paralleled by enhanced remyelination, neuronal survival, and monoaminergic innervation, reduced astrogliosis, and activation of microglia. Together, these findings suggest that application of small organic compounds that bind to L1 and stimulate the beneficial homophilic L1 functions may prove to be a valuable addition to treatments of nervous system injuries.

Local Infiltration Analgesia Versus Continuous Femoral Nerve Block in Pain Relief After Total Knee Arthroplasty: A Randomized Controlled Trial

BACKGROUND

Although both local infiltration analgesia (LIA) and continuous femoral nerve block (FNB) are common analgesic modalities for pain relief after total knee arthroplasty (TKA), we are aware of no parallel-group, randomized controlled trial that has solely compared the efficacy of LIA and continuous FNB.

METHODS

We conducted a prospective, 2-arm, parallel-group, randomized controlled trial involving patients scheduled for TKA. A total of 45 patients were randomly assigned to either the LIA or the continuous FNB group. Except for the analgesic modality, perioperative managements were identical in both groups. The primary outcome was postoperative pain score at rest 1 day after surgery, measured using a 100-mm visual analog scale.

RESULTS

Patients in the LIA group had a significantly lower visual analog scale score at rest 1 day after surgery than those in the continuous FNB group (34 ± 10 vs 42 ± 13 mm; P = .028). The opioid consumption during the initial 24 hours was significantly lower in the LIA group (12 ± 4 vs 16 ± 7 mg; P = .031). There were no differences in the rate of complications between the groups.

CONCLUSION

LIA was associated with better pain relief with a comparable complications rate for patients undergoing TKA than FNB. We recommend LIA for pain relief after TKA.

[Comparison of the Effect of Periarticular Infiltration Analgesia versus Sciatic Nerve Block for Total Knee Arthroplasty]

BACKGROUND

Sciatic nerve block (SNB) is widely used as a supplemental analgesia after total knee arthroplasty (TKA) combined with femoral nerve block (FNB). Despite its effectiveness, SNB often causes peroneal nerve paralysis, which makes it difficult to detect peroneal nerve injury by surgical process. Recently, periarticular infiltration analgesia (PIA) is reported that it provides analgesia without peroneal nerve paralysis. We conducted a retrospective analysis to compare the effectiveness of SNB and PIA.

METHODS

This study was approved by the local institutional ethics committee; 17 patients undergoing TKA under general anesthesia with continuous femoral nerve block were enrolled in the study. All patients received continuous FNB. Nine patients received sciatic nerve block successively, while 8 patients received PIA around the time of insertion of artificial joint. Primary outcome measure was the frequency of peroneal nerve paralysis when the patients woke up. Secondary outcome measures included numerical rating scale (NRS) until postoperative day 3.

RESULTS

While there were 6 patients who had peroneal nerve paralysis in the SNB group, none of them had it in the PIA group (P = 0.009). There were no significant differences of the NRSs between the two groups.

CONCLUSIONS

PIA provided sufficient analgesia after TKA without peroneal nerve paralysis.

The use of exparel (liposomal bupivacaine) to manage postoperative pain in unilateral total knee arthroplasty patients

Efforts continue to improve pain after total knee arthroplasty (TKA) in order to allow for accelerated rehabilitation. The purpose of this study was to evaluate pain control after TKA. A randomized prospective study of 80 consecutive patients was performed comparing Exparel versus femoral nerve block (FNB). Inpatient pain control was the primary outcome. Secondary outcome measures included ROM (extension and flexion), nausea and vomiting, narcotic consumption, ambulation distance, and length of stay (LOS). There were no statistically significant differences between the groups with regard to pain, nausea and vomiting, and narcotic consumption. The FNB group had greater flexion but the Exparel group had improved early ambulation and decreased LOS. Exparel provided similar pain relief to a FNB after TKA without compromising early rehabilitation.

Comparison Between Liposomal Bupivacaine and Femoral Nerve Block in Patients Undergoing Primary Total Knee Arthroplasty

This study sought to evaluate opioid consumption, hospitalization costs, and length of stay when surgical site periarticular infiltration of liposomal bupivacaine is used after total knee arthroplasty (TKA). Sixty-six consecutive primary TKA cases performed with a single-injection femoral nerve block before this date were compared with 59 consecutive TKA cases performed with the liposomal bupivacaine cocktail after this date. The mean amount of postsurgical opioids consumed was 199 mg versus 121 mg (p = .075), the average hospitalization cost was $28,546 versus $26,472 (p < .001), and the average length of stay was 2.05 days versus 1.58 days (p < .001) in the femoral nerve block versus liposomal bupivacaine group, respectively. There were no significant demographic differences between the two groups. Liposomal bupivacaine infiltration before primary wound closure may be an effective means in lowering hospitalization costs, decreasing length of stay, and decreasing postsurgical opioid consumption after TKA.

A randomized comparison of proximal and distal ultrasound-guided adductor canal catheter insertion sites for knee arthroplasty

OBJECTIVES

Proximal and distal (mid-thigh) ultrasound-guided continuous adductor canal block techniques have been described but not yet compared, and infusion benefits or side effects may be determined by catheter location. We hypothesized that proximal placement will result in faster onset of saphenous nerve anesthesia, without additional motor block, compared to a distal technique.

METHODS

Preoperatively, patients receiving an ultrasound-guided nonstimulating adductor canal catheter for knee arthroplasty were randomly assigned to either proximal or distal insertion. A local anesthetic bolus was administered via the catheter after successful placement. The primary outcome was the time to achieve complete sensory anesthesia in the saphenous nerve distribution. Secondary outcomes included procedural time, procedure-related pain and complications, postoperative pain, opioid consumption, and motor weakness.

RESULTS

Proximal insertion (n = 23) took a median (10th-90th percentiles) of 12.0 (3.0-21.0) minutes versus 6.0 (3.0-21.0) minutes for distal insertion (n = 21; P= .106) to anesthetize the medial calf. Only 10 of 25 (40%) and 10 of 24 (42%) patients in the proximal and distal groups, respectively, developed anesthesia at both the medial calf and top of the patella (P= .978). Bolus-induced motor weakness occurred in 19 of 25 (76%) and 16 of 24 (67%) patients in the proximal and distal groups (P = .529). Ten of 24 patients (42%) in the distal group required intravenous morphine postoperatively, compared to 2 of 24 (8%) in the proximal group (P = .008), but there were no differences in other secondary outcomes.

CONCLUSIONS

Continuous adductor canal blocks can be performed reliably at both proximal and distal locations. The proximal approach may offer minor analgesic and logistic advantages without an increase in motor block.

Ultrasound-guided continuous adductor canal block for analgesia after total knee replacement

BACKGROUND

There 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.

METHODS

Sixty 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.

RESULTS

There 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.

CONCLUSIONS

Continuous 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.

Ultrasound guided femoral nerve block and lateral femoral cutaneous nerve block for postoperative pain control after primary hip arthroplasty: a retrospective study

PURPOSE

The purpose of this study was to evaluate the use of an ultrasound guided femoral nerve (FN) block together with an ultrasound guided lateral femoral cutaneous nerve (LFCN) block in addition to a patient controlled intravenous analgesia (PCIA) pump with piritramide as a strategy for postoperative pain-management after primary hip arthroplasty.

METHODS

In a retrospective study, data recorded from 32 patients undergoing primary hip arthroplasty in 2008, before peripheral blocks were used, were compared with data from 38 patients undergoing primary hip arthroplasty in 2011, when an ultrasound guided single shot FN and LFCN block was used. As primary endpoint the total piritramide consumption after 48 hours was analyzed. A score on a visual analog pain scale at rest and during movement was included as a secondary outcome.

RESULTS

Patients receiving the peripheral nerve blocks used significantly less piritramide in comparison to the patients who received no peripheral nerve blocks (p < 0.01). Moreover, pain scores at rest and during movement were significantly lower in the group with the peripheral nerve block (p-values respectively < 0.01 and < 0.05).

CONCLUSIONS

This retrospective study indicates that a FN block in combination with a LFCN block as supplementary postoperative analgesia after primary hip arthroplasty, can reduce the piritramide consumption. Furthermore, patients receiving the peripheral nerve block report lower pain scores at rest and during movement compared with the patients who did not receive a peripheral block. However, as this is a retrospective study, conclusions have to be drawn cautiously.

[Comparative assessment of prolonged femoral nerve blockade and epidural analgesia for postoperative pain in total knee joint arthroplasty]

The study deals with two mostly discussed techniques of postoperative analgesia for total knee joint arthroplasty. Surgeries were performed under subarachnoid anaesthesia with intravenous sedation. 9 patients of first group in received prolonged femoral nerve blockade as a component of multimodal analgesia. 8 patients of second group received epidural infusion of naropine. If basic technique of analgesia was not effective patients received trimeperidine 20 mg intramuscular. Patients of second group had less pain syndrome (in order to visual analogue scale) and did not need additional administration of opioids.

Plasma concentrations of bupivacaine after spinal anesthesia with single shot femoral nerve block in total knee arthroplasty

BACKGROUND

Femoral nerve block is commonly established for postoperative analgesia in total knee arthroplasty but no evidence of plasma bupivacaine level has been reported.

OBJECTIVE

Determine the plasma concentrations of bupivacaine in patients who had single-injection of femoral nerve block.

MATERIAL AND METHOD

A prospective observational study was undertaken with 25 patients scheduled for unilateral total knee arthroplasty under spinal anesthesia and single shot femoral nerve block with 20 mL of 0.5% bupivacaine. Venous blood samples were collected at 0, 5, 10, 15, 30, 60, 90, and 120 minutes after femoral nerve block. Plasma bupivacaine levels were analyzed by high performance liquid chromatography with tandem mass spectrometry.

RESULTS

Four males and 21 females, ASA I-II were enrolled in the present study. Mean age, body mass index, and serum albumin level were 69.9 +/- 5.95 years, 27 +/- 3.67 kg/m2, and 4.46 +/- 0.26 mg/dL, respectively. The median of peak plasma concentration was 538.35 ng/mL (min = 176.30, max = 1,383.99) at 60 minutes after femoral nerve block, while the maximal plasma concentration of bupivacaine was 1,883.39 ng/mL at 10 minutes. None showed signs or symptoms of bupivacaine toxicity.

CONCLUSION

Peak plasma concentrations of bupivacaine were demonstrated at 60 minutes after a single shot femoral nerve block, and no signs or symptoms of bupivacaine toxicity were observed Therefore, single shot femoral nerve block with 20 mL of 0.5% bupivacaine is safe.

[Comparison of postoperative pain relief by continuous femoral nerve block and that by epidural block during physiotherapy after minimally invasive surgery of total knee arthroplasty and uni-condylar knee arthroplasty]

BACKGROUND

We compared postoperative pain relief during physiotherapy after minimally invasive surgery (MIS) of total knee arthroplasty (TKA) and unicondylar arthroplasty (UKA).

METHODS

Ninety-five patients scheduled for TKA or UKA under spinal anesthesia were divided into continuous femoral nerve block (0.1-0.12% ropivacaine 4 ml x hr(-1)) combined with a single sciatic block (Group CFNB) and epidural block (0.1-0.19% ropivacaine 4 ml x hr(-1)) combined with a single femoral block (Group EP). Visual analogue scale (VAS) at rest, walking, maximal knee flexion, extension, and maximal pain on POD 1 were recorded. Patient's satisfaction of analgesia and supplemental analgesics on POD 1 were recorded. We compared VAS and satisfaction of TKA with UKA during CFNB or EP.

RESULTS

VAS at physiotherapy was higher than VAS at rest. VAS at maximal knee flexion was higher than VAS at rest, walking or maximal knee extension in UKA of Group CFNB (n = 29) or EP (n = 19). VAS at flexion and extension were higher than VAS at walk- ing in TKA of Group CFNB (n = 20) or EP (n = 27). VAS, patient's satisfaction and supplemental analgesics on POD 1 were comparable in both groups.

CONCLUSIONS

VAS at physiotherapy after TKA or UKA during CFNB or EP was very severe than VAS at rest.

Ultrasound-guided femoral nerve block as a diagnostic aid in demonstrating quadriceps involvement in bovine spastic paresis

The aim of this study was to evaluate the clinical effects of a femoral nerve block via a dorsal paralumbar injection in healthy calves and calves suffering from spastic paresis. Based on bony landmarks and using ultrasound guidance, the femoral nerves of eight healthy calves were blocked bilaterally with a 4% procaine solution containing blue dye. In 11/16 nerve blocks, paralysis of the quadriceps muscle was obtained after dorsal paralumbar injection. Paralysis was total in 8/16 cases. The injection site was confirmed by post mortem dissection, and in 12/16 cases, the blue dye was found <2mm from the nerve. Clinical use of the technique was then demonstrated in two cases of atypical bovine spastic paresis. In such calves an objective diagnostic tool is required to identify those calves which are suitable for partial tibial neurectomy. The femoral nerve block used in this study has the potential to be such a method and can be used to establish the involvement of the quadriceps femoris in calves suffering from the quadriceps or mixed presentation form of spastic paresis.

[Control of postoperative pain in knee arthroplasty: single dose femoral nerve block versus continuous femoral block]

INTRODUCTION

To compare the efficacy of a multimodal analgesia with 2 different techniques (femoral nerve block with a single dose and continuous femoral nerve block) in the control of pain, use of opioids, and secondary effects in patients subjected to total knee replacement.

MATERIAL AND METHODS

A prospective randomised study of patients subjected to knee replacement with subarachnoid anaesthesia. The postoperative analgesia consisted of tramadol, dexketoprofen and paracetamol, and one of the following techniques: Femoral nerve block with a single dose of 30mL of 0.5% ropivacaine, or that dose plus a continuous infusion via a femoral catheter of 0.375% ropivacaine 6ml/h for 48h. The demographic, anaesthetic and surgical variables were recorded, along with the pain intensity using a visual analogue scale, opioid use, and complications at 24 and 48h after surgery.

RESULTS

A total of 104 patients were included. There no differences in the demographic data between the groups. The pain intensity was lower in the group that had continuous femoral block, particularly at 48h, compared to the single-dose block, and with a lower use of rescue analgesia in the continuous femoral block. The incidence in secondary effects was similar, with a lower long-term sensory block being observed in the femoral block with a single dose.

CONCLUSIONS

The use of peripheral nerve block is accepted practice for analgesia after knee replacement surgery. Continuous femoral block is a valid alternative, decreasing the use of rescue opiates and pain intensity (particularly at 48h) compared to isolated femoral block.

US-guided femoral and sciatic nerve blocks for analgesia during endovenous laser ablation

PURPOSE

Endovenous laser ablation may be associated with significant pain when performed under standard local tumescent anesthesia. The purpose of this study was to investigate the efficacy of femoral and sciatic nerve blocks for analgesia during endovenous ablation in patients with lower extremity venous insufficiency.

METHODS

During a 28-month period, ultrasound-guided femoral or sciatic nerve blocks were performed to provide analgesia during endovenous laser ablation in 506 legs and 307 patients. The femoral block (n = 402) was performed at the level of the inguinal ligament, and the sciatic block at the posterior midthigh (n = 124), by injecting a diluted lidocaine solution under ultrasound guidance. After the blocks, endovenous laser ablations and other treatments (phlebectomy or foam sclerotherapy) were performed in the standard fashion. After the procedures, a visual analogue pain scale (1-10) was used for pain assessment.

RESULTS

After the blocks, pain scores were 0 or 1 (no pain) in 240 legs, 2 or 3 (uncomfortable) in 225 legs, and 4 or 5 (annoying) in 41 legs. Patients never experienced any pain higher than score 5. The statistical analysis revealed no significant difference between the pain scores of the right leg versus the left leg (p = 0.321) and between the pain scores after the femoral versus sciatic block (p = 0.7).

CONCLUSIONS

Ultrasound-guided femoral and sciatic nerve blocks may provide considerable reduction of pain during endovenous laser and other treatments, such as ambulatory phlebectomy and foam sclerotherapy. They may make these procedures more comfortable for the patient and easier for the operator.

Effect of combined single-injection femoral nerve block and patient-controlled epidural analgesia in patients undergoing total knee replacement

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.

A multicenter, randomized, triple-masked, placebo-controlled trial of the effect of ambulatory continuous femoral nerve blocks on discharge-readiness following total knee arthroplasty in patients on general orthopaedic wards

A continuous femoral nerve block (cFNB) involves the percutaneous insertion of a catheter adjacent to the femoral nerve, followed by a local anesthetic infusion, improving analgesia following total knee arthroplasty (TKA). Portable infusion pumps allow infusion continuation following hospital discharge, raising the possibility of decreasing hospitalization duration. We therefore used a multicenter, randomized, triple-masked, placebo-controlled study design to test the primary hypothesis that a 4-day ambulatory cFNB decreases the time until each of three predefined readiness-for-discharge criteria (adequate analgesia, independence from intravenous opioids, and ambulation 30m) are met following TKA compared with an overnight inpatient-only cFNB. Preoperatively, all patients received a cFNB with perineural ropivacaine 0.2% from surgery until the following morning, at which time they were randomized to either continue perineural ropivacaine (n=39) or switch to normal saline (n=38). Patients were discharged with their cFNB and portable infusion pump as early as postoperative day 3. Patients who were given 4 days of perineural ropivacaine attained all three criteria in a median (25th-75th percentiles) of 47 (29-69)h, compared with 62 (45-79)h for those of the control group (Estimated ratio=0.80, 95% confidence interval: 0.66-1.00; p=0.028). Compared with controls, patients randomized to ropivacaine met the discharge criterion for analgesia in 20 (0-38) versus 38 (15-64)h (p=0.009), and intravenous opioid independence in 21 (0-37) versus 33 (11-50)h (p=0.061). We conclude that a 4-day ambulatory cFNB decreases the time to reach three important discharge criteria by an estimated 20% following TKA compared with an overnight cFNB, primarily by improving analgesia.

Complications of femoral nerve block for total knee arthroplasty

Preemptive and multimodal pain control protocols have been introduced to enhance rehabilitation after total knee arthroplasty (TKA). We determined the complication rate associated with preoperative femoral nerve block (FNB) for TKA. Among 1018 TKA operations, we performed 709 FNBs using a single-injection technique into the femoral nerve sheath and confirming position with nerve stimulation before induction. After TKA, weightbearing as tolerated was initiated using a walker or crutches on postoperative Day 1. Twelve patients (1.6%) treated with FNB sustained falls, three (0.4%) of whom underwent reoperations. Five patients had postoperative femoral neuritis, which may have been secondary to the block. One patient had new onset of atrial fibrillation after FNB, and the TKA was postponed. Femoral nerve block before TKA is not a harmless intervention. We recommend postoperative protocols be modified for patients who have FNB to account for decreased quadriceps function in the early postoperative period, which can lead to falls.

LEVEL OF EVIDENCE

Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

[The effects of two different multimodal analgesic regimens in total hip replacement surgery]

OBJECTIVES

This study evaluated the effectiveness of two different multimodal analgesia protocols in terms of postoperative pain relief, tramadol consumption during patient-controlled analgesia (PCA) and side effects after total hip replacement surgery.

METHODS

Group F (n=18) received general anesthesia after a 3-in-1 femoral nerve block (FNB) was applied using 40 ml of bupivacaine 0.25%. Group FD (n=18) received general anesthesia after the same block and dexketoprofen p.o. was given. All patients received intravenous tramadol at the end of surgery via a PCA device. Group FD was given dexketoprofen 75 mg/day for 48 hours postoperatively. Pain scores were evaluated at 0, 1/2, 1, 4, 8, 12, 24 and 48h at rest and on movement of the hip. Side effects and global satisfaction scores in both groups were also evaluated in this setting.

RESULTS

Total tramadol consumption was lower in Group FD (377.7+/-137.4) than in Group F (593.9+/-132.3) (p<0.05). Visual analogue scale (VAS) scores were </=3 in all follow-up periods in both groups. While in Group FD, 6 patients had nausea, 3 vomiting and 1 sedation, in Group F, 5 patients had nausea, 3 vomiting and 2 sedation. Patient global satisfaction scores in Group F were very good in 14 patients and good in 4 patients, and in Group FD were very good in 13 patients and good in 5 patients.

CONCLUSION

Both analgesia protocols were effective in pain relief in total hip replacement patients, with similar side effects. The effect of additional dexketoprofen was to reduce postoperative tramadol consumption.

Ethanol reduces motoneuronal excitability and increases presynaptic inhibition of Ia afferents in the human spinal cord

INTRODUCTION

Already low blood concentrations of ethanol acutely impair motor control and coordination. In vitro experiments have given evidence that spinal effects of ethanol contribute to this by reducing spinal excitability and enhancing presynaptic inhibition of Ia fibers. In this study, we investigated the influence of 0.7 g per kilogram of bodyweight ethanol on motoneuronal excitability and presynaptic inhibition in humans.

METHODS

The study was performed in 10 volunteers. Spinal excitability was measured by the maximal H-reflex of the soleus muscle normalized to the maximal muscular response (Hmax/Mmax). Presynaptic inhibition was measured by changes in heteronymous Ia-facilitation of the soleus H-reflex, which is achieved by stimulation of the femoral nerve. A decrease in facilitation can be ascribed to an increase in presynaptic inhibition. Changes of these parameters under the influence of 0.7 g per kilogram of bodyweight ethanol were assessed in comparison to control measurements before ethanol application.

RESULTS

Both parameters, Hmax/Mmax and Heteronymous facilitation, were significantly reduced under the influence of ethanol (Wilcoxon signed-rank test with Bonferroni correction for each, p<0.01).

DISCUSSION

The increase in presynaptic inhibition by ethanol is probably caused by an increase in GABAA receptor-mediated Cl-conductance, which has been shown in spinal cord cultures. The role of presynaptic inhibition in movement is assumed to be there to control the afferent input of muscle spindles and tendon organs as a mechanism of specific input-selection. This study demonstrated that ethanol reduces spinal excitability and increases GABAergic presynaptic inhibition on Ia afferent fibers in humans.

Postoperative Analgesia After Knee Surgery: A Comparison of Three Different Concentrations of Ropivacaine for Continuous Femoral Nerve Blockade

BACKGROUND

The most effective ropivacaine concentration for femoral infusion after total knee arthroplasty is currently ill defined. We designed the present study to compare ropivacaine in three different concentrations (0.1, 0.2, and 0.3%) to evaluate analgesic quality, when administered as a continuous infusion with frequent infusion adjustments in patients receiving a combined femoral and sciatic nerve block. Secondary aims were to evaluate side effects such as motor blockade, rehabilitation indices, and ropivacaine plasma concentrations.

METHODS

One hundred twenty-two patients undergoing total knee arthroplasty under combined general and regional anesthesia received femoral infusions of ropivacaine 0.1, 0.2, or 0.3%. Infusions were started after initial loading doses of 30 mL ropivacaine 0.5% into the femoral catheter and a sciatic catheter and were targeted to dynamic pain scores of 40 mm. Pain and side effects were assessed 1 h after tracheal extubation and on the first, second, third, fourth, and fifth postoperative days. Ropivacaine plasma concentrations were measured 24, 48, and 72 h after the start and 24 h after termination of femoral infusions in patients receiving ropivacaine 0.2% or 0.3%.

RESULTS

Ropivacaine 0.1% provided ineffective analgesia. Ropivacaine 0.2% and 0.3% provided equivalent analgesia. Maximum infusion rates were 15.39 and 13.77 mL/h for ropivacaine 0.2% and 0.3%, respectively. There were no significant differences in motor blockade, mobilization, or ropivacaine plasma concentrations, which remained below toxic levels throughout the study period.

CONCLUSION

Ropivacaine 0.2% and 0.3% were similar in terms of analgesic quality. Initial infusion rates should be adjusted to 15 mL/h to obtain effective analgesia.

Effects of Intermittent Femoral Nerve Injections of Bupivacaine, Levobupivacaine, and Ropivacaine on Mitochondrial Energy Metabolism and Intracellular Calcium Homeostasis in Rat Psoas Muscle

Background

Long-acting local anesthetics cause muscle damage. Moreover, long-acting local anesthetics act as uncoupler of oxidative phosphorylation in isolated mitochondria and enhance sarcoplasmic reticulum Ca(2+) release. The aim of the study was to evaluate effects of perineural injections of local anesthetics on mitochondrial energetic metabolism and intracellular calcium homeostasis in vivo.

Methods

Femoral nerve block catheters were inserted in adult male Wistar rats. Rats were randomized and received seven injections (1 ml/kg) of bupivacaine, levobupivacaine, ropivacaine, or isotonic saline at 8-h intervals. Rats were killed 8 h after the last injection. Psoas muscle was quickly dissected from next to the femoral nerve. Local anesthetic concentrations in muscle were determined. Oxidative capacity was measured in saponin-skinned fibers. Oxygen consumption rates were measured, and mitochondrial adenosine triphosphate synthesis rate was determined. Enzymatic activities of mitochondrial respiratory chain complexes were evaluated. Local calcium release events (calcium sparks) were analyzed as well as sarcoplasmic reticulum calcium content in saponin-skinned fibers.

Results

Eight hours after the last injection, psoas muscle concentration of local anesthetics was less than 0.3 microg/g tissue. Adenosine triphosphate synthesis and adenosine triphosphate-to-oxygen ratio were significantly decreased in the muscle of rats treated with local anesthetics. A global decrease (around 50%) in all of the enzyme activities of the respiratory chain was observed. Levobupivacaine increased the amplitude and frequency of the calcium sparks, whereas lower sarcoplasmic reticulum calcium content was shown.

Conclusion

Bupivacaine, levobupivacaine, and ropivacaine injected via femoral nerve block catheters induce a deleterious effect in mitochondrial energy, whereas only levobupivacaine disturbs calcium homeostasis.

Pre- versus postoperative intraarticular application of local anesthetics and opioids versus femoral nerve block in anterior cruciate ligament repair

BACKGROUND

Often anterior cruciate ligament (ACL) reconstruction is performed as outpatient surgery. This requires a patient friendly postoperative pain management. Three common procedures were compared in this trial.

METHODS

In a prospective, randomized study the effect of postoperative pain management using preoperative intraarticular anesthesia (0.1 mg Fentanyl + 8 ml Bupivacain 0.5%) was compared with postoperative intraarticular anesthesia (0.1 mg Fentanyl + 8 ml Bupivacain 0.5%) and the femoralis 3-in-1 nerve block (20 ml Prilocain 1% + 20 ml Bupivacain 0.5%) in 157 patients who underwent arthroscopic ACL-plasty.

RESULTS

Preoperative intraarticular anesthesia and the femoralis 3-in-1 nerve block showed the same postoperative analgesia and satisfactory pain scores in most cases. Postoperative intraarticular anesthesia was less effective.

CONCLUSION

Our data show that in anterior cruciate ligament reconstruction preoperative intraarticular analgesia with Bupivacain/Fentanyl is satisfactory and equal to the femoralis 3-in-1 nerve block with Bupivacain.

[Femoral nerve block for postoperative analgesia after anterior cruciate ligament reconstruction: comparison of 2 concentrations of bupivacaine with clonidine in 3 modes of administration]

BACKGROUND

The continuous femoral nerve block is used for postoperative orthopedic analgesia.

OBJECTIVE

To evaluate 2 concentrations of bupivacaine with clonidine in 3 methods of administration for performing a continuous femoral nerve block.

MATERIAL AND METHODS

Randomized controlled trial in ASA 1-2 patients in 6 groups. In groups 1, 2, and 3, the combination used was 0.125% bupivacaine plus clonidine. In groups la, 2a, and 3a, the combination was 0.0625% bupivacaine plus clonidine. Methods of administration were as follows: groups 1 and la, 10 mL x h(-1) in continuous infusion; groups 2 and 2a, 5 mL h x (-1) in continuous infusion plus 2.5 mL every 30 minutes through a patient-controlled analgesia (PCA) system; groups 3 and 3a, 5 mL every 30 minutes in a PCA system. Pain on a visual analog scale (VAS) and amounts of bupivacaine and morphine used were recorded 2 and 48 hours after surgery.

RESULTS

A total of 105 patients were enrolled: 17 in group 1, 18 in group la, 18 in group 2, 17 in group 2a, 17 in group 3, and 18 in group 3a. No significant differences between any of the 6 groups were observed for patient characteristics, postoperative VAS scores, or morphine use.

CONCLUSIONS

A continuous femoral nerve block is useful for managing pain after anterior cruciate ligament surgery. The application of 5 mL x h(-1) in continuous infusion or in PCA system bolus doses provides excellent postoperative analgesia. Use of 0.0625% bupivacaine decreases overall consumption of analgesic and is not detrimental to quality of analgesia.

Central excitability does not limit postfatigue voluntary activation of quadriceps femoris

After fatigue, motor evoked potentials (MEP) elicited by transcranial magnetic stimulation and cervicomedullary evoked potentials elicited by stimulation of the corticospinal tract are depressed. These reductions in corticomotor excitability and corticospinal transmission are accompanied by voluntary activation failure, but this may not reflect a causal relationship. Our purpose was to determine whether a decline in central excitability contributes to central fatigue. We hypothesized that, if central excitability limits voluntary activation, then a caffeine-induced increase in central excitability should offset voluntary activation failure. In this repeated-measures study, eight men each attended two sessions. Baseline measures of knee extension torque, maximal voluntary activation, peripheral transmission, contractile properties, and central excitability were made before administration of caffeine (6 mg/kg) or placebo. The amplitude of vastus lateralis MEPs elicited during minimal muscle activation provided a measure of central excitability. After a 1-h rest, baseline measures were repeated before, during, and after a fatigue protocol that ended when maximal voluntary torque declined by 35% (Tlim). Increased prefatigue MEP amplitude ( P = 0.055) and cortically evoked twitch ( P < 0.05) in the caffeine trial indicate that the drug increased central excitability. In the caffeine trial, increased MEP amplitude was correlated with time to task failure ( r = 0.74, P < 0.05). Caffeine potentiated the MEP early in the fatigue protocol ( P < 0.05) and offset the 40% decline in placebo MEP ( P < 0.05) at Tlim. However, this was not associated with enhanced maximal voluntary activation during fatigue or recovery, demonstrating that voluntary activation is not limited by central excitability.