Continuous femoral nerve blocks: decreasing local anesthetic concentration to minimize quadriceps femoris weakness

Motor-Sparing Effect of Adductor Canal Block for Knee Analgesia: An Updated Review and a Subgroup Analysis of Randomized Controlled Trials Based on a Corrected Classification System

OBJECTIVE

Discrepancies in the definition of adductor canal block (ACB) lead to inconsistent results. To investigate the actual analgesic and motor-sparing effects of ACB by anatomically defining femoral triangle block (FTB), proximal ACB (p-ACB), and distal ACB (d-ACB), we re-classified the previously claimed ACB approaches according to the ultrasound findings or descriptions in the corresponding published articles. A meta-analysis with subsequent subgroup analyses based on these corrected results was performed to examine the true impact of ACB on its analgesic effect and motor function (quadriceps muscle strength or mobilization ability). An optimal ACB technique was also suggested based on an updated review of evidence and ultrasound anatomy.

MATERIALS AND METHODS

We systematically searched studies describing the use of ACB for knee surgery. Cochrane Library, PubMed, Web of Science, and Embase were searched with the exclusion of non-English articles from inception to 28 February 2022. The motor-sparing and analgesic aspects in true ACB were evaluated using meta-analyses with subsequent subgroup analyses according to the corrected classification system.

RESULTS

The meta-analysis includes 19 randomized controlled trials. Compared with the femoral nerve block group, the quadriceps muscle strength (standardized mean difference (SMD) = 0.33, 95%-CI [0.01; 0.65]) and mobilization ability (SMD = -22.44, 95%-CI [-35.37; -9.51]) are more preserved in the mixed ACB group at 24 h after knee surgery. Compared with the true ACB group, the FTB group (SMD = 5.59, 95%-CI [3.44; 8.46]) has a significantly decreased mobilization ability at 24 h after knee surgery.

CONCLUSION

By using the corrected classification system, we proved the motor-sparing effect of true ACB compared to FTB. According to the updated ultrasound anatomy, we suggested proximal ACB to be the analgesic technique of choice for knee surgery. Although a single-shot ACB is limited in duration, it remains the candidate of the analgesic standard for knee surgery on postoperative day 1 or 2 because it induces analgesia with less motor involvement in the era of multimodal analgesia. Furthermore, data from the corrected classification system may provide the basis for future research.

Adductor Canal Blocks Are Not Associated With Improved Early Postoperative Outcomes in Patients Undergoing Total Knee Arthroplasty

Background: As length of stay after total knee arthroplasty (TKA) continues to shorten, interventions that may reduce early postoperative pain and complications must be studied. Peripheral nerve block is being explored as a potential means of improving pain management. The purpose of this study was to evaluate the impact of adductor canal block (ACB) on postoperative outcomes for patients undergoing TKA. Methods: We conducted a retrospective review of 565 patients who received unilateral TKA under spinal anesthesia with a periarticular anesthetic injection. Patients were divided by ACB status. Univariate comparisons and multivariate regression were used to compare outcomes for patients receiving ACBs vs those who did not. Results: Of the 565 patients, 167 received an ACB, and 398 did not. Patients who received an ACB were less likely to require nausea medication during the immediate postoperative period. Length of stay, narcotic consumption, rate of discharge to home, postanesthesia care unit recovery time, urinary retention, ability to complete physical therapy, and 30-day readmission rate did not differ significantly between groups. After risk adjustment, the only significant finding was decreased likelihood of nausea in patients receiving an ACB. Conclusion: ACBs appear to have little to no significant impact on early clinical outcomes in patients having TKA under spinal anesthesia with a periarticular anesthetic injection. Further study of larger patient cohorts is required to validate these findings.

Positioning the Catheter Tip Anterior or Posterior to the Saphenous Nerve in Continuous Adductor Canal Block: A Mono-Centric Retrospective Comparative Study

Background and Aim

Ultrasound-guided continuous adductor canal block (cACB) is a conventional choice in patients undergoing total knee arthroplasty (TKA) for the management of the postoperative pain. This study aims to compare different catheter tip locations for cACB relative to the saphenous nerve (anteriorly vs posteriorly) in terms of efficacy and complications.

Methods

At the department of Surgical Sciences, Orthopedic Trauma and Emergencies of the University of Naples Federico II (Naples, Italy), between January 2020 and November 2021, retrospective comparative study was executed. Patients planned for TKA were included in the study if they met the follow inclusion criteria: patients undergone TKA; aged 50-85 years; body mass index (BMI) of 18-35 kg/m2; American Society of Anesthesiologists (ASA) physical status classification from I to III; subarachnoid technique for anesthesiology plane; continuous adductor canal block performed by an anesthetist with considerable experience. Patients were assigned to receive cACB with the catheter tip located anteriorly (Group 1, G1) or posteriorly to the saphenous nerve (Group 2, G2). Postoperative pain, ambulation ability, episodes of pump block and rate of catheter dislodgement and leakage were evaluated and analyzed.

Results

Altogether, 102 patients were admitted to the study (48 in G1 and 54 in G2). After the first 8 postoperative hours, in G1 17 patients (35.4%) had a VAS greater than 4, while in group 2 only 3 patients (5.6%) had a VAS greater than 4 (p-value <0.01). All patients of both groups showed ambulation ability in the postoperative period. No episode of leakage was recorded. While the catheter displacement rate was similar in the two groups (2.1% for G1 vs 3.7% for G2; p-value >0.05), the episodes of pump block were significantly less in G2 than in G1 (3.7% vs 20.8%; p-value <0.01).

Conclusion

In cACB for TKA, we found that positioning the catheter tip posteriorly to the saphenous nerve may lead to a greater postoperative analgesia and reduce the risk of pump block compared to placing the catheter tip anteriorly to the nerve.

Synergistic effects of robotic surgery and IPACK nerve block on reduction of opioid consumption in total knee arthroplasty

Background

There are numerous strategies to combat postoperative analgesia and expedite recovery after total knee arthroplasty (TKA). The purpose of this study was to determine opioid consumption, length of stay, and functional outcomes after robotic versus standard TKA in the setting of various regional pain modalities.

Methods

A consecutive series of patients treated with unilateral primary robotic or standard TKA from January 2018-February 2021 were retrospectively identified. Regional pain modalities included peri-articular injection (PAI), adductor canal block (ACB), and infiltration between popliteal artery and capsule of knee (IPACK). Patient demographics, operative/perioperative variables, and postoperative function were recorded. Daily opiate consumption was calculated as morphine milligram equivalents (MME). Multivariate regression was performed to control for age, sex, and race.

Results

After review, 283 patients (177 Females; 106 Males) were included. Robotic TKA patients received IPACK + ACB (36), while standard TKA patients received either ACB (45), IPACK + ACB (167), or PAI (35). Daily inpatient opioid consumption in the standard IPACK + ACB (p = 0.02) and robotic IPACK + ACB groups (p = 0.0001) was significantly lower compared to standard ACB. When combined with IPACK block, robotic procedures synergistically lowered opiate consumption (p = 0.004) compared to standard procedures and led to earlier discharge (p = 0.003). The robotic IPACK + ACB cohort also demonstrated improved early ambulation compared to standard ACB, (p = 0.05), whereas the same benefit was not seen for patients who received IPACK during standard TKA.

Conclusions

The utilization of IPACK block decreases inpatient postoperative opioid requirements following TKA. Robotic TKA and IPACK block appeared to have a synergistic effect on opioid consumption and postoperative recovery.

Effectiveness of continuous femoral nerve block for pain relief after total knee arthroplasty: comparison with epidural patient-controlled analgesia and periarticular injection

OBJECTIVE

To compare the clinical outcomes among three analgesic techniques, continuous femoral nerve block (CFNB), epidural patient-controlled analgesia (EPCA) and periarticular injection (PAI), in patients undergoing total knee arthroplasty (TKA).

METHODS

This retrospective case-control study enrolled patients that underwent TKA. Visual analogue scale (VAS) pain scores, sleep disturbance, additional opioid consumption and incidence of opioid-related side-effects were assessed.

RESULTS

A total of 120 patients were categorized into three groups: EPCA (group A, n = 40), PAI (group B, n = 40) and CFNB (group C, n = 40). Group C had significantly lower VAS pain scores than groups A and B at 8, 12 and 24 h after TKA. There were no significant differences in VAS pain scores among the three groups from 48 h after TKA. Sleep quality on the first day after surgery was significantly better in group C than in groups A and B. Additional opioid consumption was significantly lower in the group C than in the groups A and B. Group C showed a lower rate of opioid-related side-effects than groups A and B.

CONCLUSION

CFNB was a more effective additional analgesic technique than EPCA or PAI for acute postoperative pain control within 24 h of TKA.

Hand-Held Dynamometry in the Inpatient Care Setting After Total Knee Arthroplasty: Reliability of Static Knee Strength Measurements

OBJECTIVE

The aim of the study was to determine intrarater and interrater reliabilities for static strength assessment of knee flexors and knee extensors in patients with total knee arthroplasty, during the acute postoperative rehabilitation.

DESIGN

Forty-five total knee arthroplasty patients were included in the study. Two physical therapists performed strength assessments by using hand-held dynamometry. Patients performed three trials and a 30-sec rest was provided between each trial. After this, a 5-min rest was provided, and then, a second investigator performed the same procedure for interrater reliability. Assessments for intrarater reliability were performed 1 hr later.

RESULTS

The intrarater reliability of knee extensors and knee flexors strength measurements were 0.96 and 0.94, respectively. The standard error of measurement and minimal detectable change 95% confidence level were 6.17 and 17.01 Nm for knee extensors and were 8.89 and 24.51 Nm for knee flexors, respectively. The interrater reliability of knee flexors and knee extensors strength measurement was 0.96 for both. The standard error of measurement and minimal detectable change values at 95% confidence level were 6.00 and 16.54 Nm for knee extensors and were 6.32 and 17.42 Nm for knee flexors, respectively.

CONCLUSIONS

Hand-held dynamometry is a reliable method to assess static knee strength. Hand-held dynamometry assessment can be implemented during acute postoperative rehabilitation. Our results may assist the clinicians in determining an accurate postoperative rehabilitation program after total knee arthroplasty surgery.

Regional Anesthesia in the Field for Trauma Victims

This article addresses the importance of anesthesiologists providing regional anesthesia techniques that are beneficial to the care of trauma patients in the field. It also discusses the advantages and risks associated with regional anesthesia in the field along with how to avoid those risks. In addition, it describes some of the benefits of modern ultrasound techniques compared with landmark techniques with stimulation and other important considerations when performing regional anesthesia in the field. The article gives the unique indications, risks, and key points of the most useful regional techniques for anesthesiologists operating in field environments.

The efficacy and safety of the infiltration of the interspace between the popliteal artery and the capsule of the knee block in total knee arthroplasty: A prospective randomized trial protocol

BACKGROUND

Total knee arthroplasty (TKA) is an established and successful surgical procedure which is the major treatment for degenerative knee joint diseases. A novel technique to address posterior knee joint pain is the infiltration of local anesthetic between the interspace between the popliteal artery and capsule of the knee (IPACK). The goal of this randomized clinical trial was to assess the efficacy and safety of adding IPACK to adductor canal block (ACB) after TKA.

METHODS

This was a prospectively randomized trial that investigated the effectiveness and safety of the IPACK after TKA. Approval from Clinical Studies Ethical Committee in Qilu Hospital of Shandong University was obtained. The inclusion criteria were adult patients undergoing primary unilateral TKA and American Society of Anesthesiologists grade 1 or 2 with normal cognitive function. The patients were randomized to 1 of 2 treatment options: ACB-alone group and ACB + IPACK group. The primary outcome was the total morphine consumption during postoperative 24 hours. Secondary outcomes included postoperative pain score, time to first and total dosage of rescue morphine in postoperative 48 hours, early and late postoperative period (from postoperative day 0-3 months follow-up) performance-based test (Timed-Up and Go test, and quadriceps strength). Postoperative nausea and vomiting, length of hospital stay, patient satisfaction, and other adverse events were also evaluated.

RESULTS

It was hypothesized that when combined with a control group, the IPACK block would result in a lower morphine consumption and pain score after TKA.

TRIAL REGISTRATION

This study protocol was registered in Research Registry (researchregistry5765).

The Effect of the IPACK Block on Pain After Primary TKA: A Double-Blinded, Prospective, Randomized Trial

BACKGROUND

The purpose of this study was to determine if infiltration of local anesthetic between the interspace between the popliteal artery and capsule of the knee (IPACK) provides benefit in total knee arthroplasty.

METHODS

Patients were randomized into continuous adductor canal block with IPACK block or continuous adductor canal block with sham subcutaneous saline injection. Only the anesthesiologist performing the block was aware of randomization status. After surgery, a blinded assessor recorded opioid consumption, pain scores, and gait distance.

RESULTS

There were 35 patients in the IPACK group and 34 in the NO IPACK group. There was no difference demographically between the groups. In the postanesthesia care unit (PACU), the average (P = .0122) and worst (P = .0168) pain scores at rest were statistically lower in the IPACK group. There was no difference in the pain scores during physical therapy (P = .2080). There was no difference in opioid consumption in the PACU (P = .7928), or at 24 hours (P = .7456). There was no difference in pain scores on POD 1 in the AM (P = .4597) or PM (P = .6273), or in the walking distance (P = .5197). There was also no difference in length of stay in the PACU (P = .9426) or hospital (P = .2141).

CONCLUSION

The IPACK group had lower pain scores at rest in the PACU, but this is likely not clinically significant. The routine use of the IPACK is not supported by the results of this study. There may be indications for the use of the IPACK block as a rescue block or in patients who have contraindications to our standard multimodal treatment regimen or in patients with chronic pain or opioid dependence.

Comparison of Effectiveness of Ropivacaine Infusion Regimens for Continuous Femoral Nerve Block for Recovery After Total Knee Arthroplasty: A Randomized Double-Blind Trial

Purpose

Continuous femoral nerve block (cFNB) is effective for analgesia after total knee arthroplasty (TKA). However, it is not clear which low-dose regimen of ropivacaine infusion for cFNB provides adequate analgesia and enables rapid recovery. The aim of this study was to compare the effects of different cFNB regimens on rehabilitation of patients after TKA.

Patients and Methods

Sixty patients scheduled for TKA were enrolled in this trial. After surgery, patients in the 0.1%, 0.15%, and 0.2% groups received infusion of 10 mL of 0.1%, 6.7 mL of 0.15%, and 5 mL of 0.2% ropivacaine per hour, respectively (n=20), at the dose of 10 mg/h for 48 h. The primary endpoint was time to readiness for discharge. The secondary endpoints were time to first walk, manual muscle testing (MMT) scores, numerical rating scale (NRS) scores at rest and movement, morphine consumption, rescue analgesia, and the incidence of adverse events.

Results

The time to readiness for discharge and the time to first walk of the 0.1% group were significantly longer than that of the 0.15% and 0.2% groups. MMT scores of the 0.2% group at 18 h after surgery were significantly lower than those of the 0.1% group. MMT scores of the 0.2% group at 24 and 48 h after surgery were also significantly lower than those of the 0.1% and 0.15% groups. NRS scores at rest and at movement in the 0.1% group were significantly higher than those in the 0.15% and 0.2% groups.

Conclusion

Patients administered the regimens of 0.15% and 0.2% ropivacaine infusion for cFNB were ready for discharge earlier than the 0.1% group after TKA, at the dose of 10 mg/h for 48 h. The regimen of 0.15% ropivacaine, which is associated with less quadriceps muscle strength weakness than 0.2%, is recommended for postoperative analgesia after TKA.

Comparison of the postoperative analgesic effect for infiltration between the popliteal artery and the capsule of the posterior knee and that of periarticular multimodal drug injection in total knee arthroplasty: retrospective study in the immediate postoperative period

Background

The aim of this study is to compare the postoperative analgesic effect of infiltration between the popliteal artery and the capsule of the knee (IPACK) and the effect of periarticular multimodal drug injection (PMDI) in addition to adductor canal block (ACB) after total knee arthroplasty.

Methods

Among patients who received total knee arthroplasty from June 2017 to December 2017, 50 who underwent ACB with additional IPACK and 50 who received ACB with additional PMDI were selected for this study. We compared the postoperative pain numerical rating scale (NRS), the number of times patient-controlled analgesia was administered and the amount administered, the total amount of opioids given, and complications associated with the procedure between the two groups.

Results

NRS measured at rest and 45° knee flexion at days 1 and 2 after surgery was significantly lower in the IPACK group than in the PMDI group. The resting NRS measured at day 3 after surgery was also significantly lower in the IPACK group than in the PMDI group, and the NRS at 45° knee flexion measured from day 3 to day 5 showed a significant reduction in the IPACK group. No complications relating to the procedure occurred.

Conclusions

IPACK may be a better option than PMDI for controlling acute phase pain in patients undergoing total knee arthroplasty.

Hybrid Blocks for Total Knee Arthroplasty: A Technical Description

INTRODUCTION

This narrative review article aims to examine current evidence of knee innervation in order to develop a technique of targeting pure sensory innervation of the knee joint without compromising motor function.

METHODS

A literature review of knee innervation was performed to gain an anatomic understanding of terminal sensory branches of the relevant target nerves (femoral, obturator, sciatic, and lateral femoral cutaneous).

RESULTS

Pure sensory block of the knee joint is challenging due to important contributions from themuscular innervation close to the joint and the variability of nerves afferents contained within and around the adductor canal.

CONCLUSION

On the basis of this anatomic knowledge we describe an ultrasound-guided 3-injection hybrid technique that represents a balance between preserving adequate motor power while still providing analgesia in a simple method.

Ultrasound-guided continuous femoral nerve block: a randomized trial on the influence of femoral nerve catheter orifice configuration (six-hole versus end-hole) on post-operative analgesia after total knee arthroplasty

BACKGROUND

Multiorifice catheters have been shown to provide superior analgesia and significantly reduce local anesthetic consumption compared with end-hole catheters in epidural studies. This prospective, blinded, randomized study tested the hypothesis that, in continuous femoral nerve block (CFNB) under ultrasound guidance, multiorifice catheter would reduce local anesthetic consumption at 24 h compared with end-hole catheter.

METHODS

Eighty adult patients (aged ≥18 years) scheduled to undergo primary total knee arthroplasty under a combination of CFNB, sciatic nerve block and general anesthesia were randomized to CFNB using either a 3-pair micro-hole (Contiplex, BRAUN®, 20G - 400 mm) or an end-hole (Silverstim VYGON®, 20G - 500 mm) catheter. Once the femoral catheter was sited, a bolus of 20 mL lidocaine 1% was injected. An electronic pump then delivered an automated 5 mL bolus of ropivacaine 0.2% hourly, with 10 mL self-administered patient controlled analgesia boluses.

RESULTS

There was no inter-group difference in either median number of ropivacaine boluses on demand during the first 24 h (4(2-7) vs. 4(2-8) in six-hole and end-hole groups, respectively; P = 0.832) or median ropivacaine consumption at 48 h (365(295-418) vs. 387(323-466); P = 0.452). No significant differences were recorded between the groups at 24 h regarding median average verbal rate pain scale (2(0-3) vs. 2(0-4); P = 0.486) or morphine consumption (0(0-20) vs. 0(0-20); P = 0.749). Quadriceps muscle strength declined to 7% (0-20) and 10% (0-28) in the six-hole and end-hole groups, respectively, at 24 h after surgery (P = 0.733).

CONCLUSIONS

In this superiority trial, catheter orifice configuration did not influence the effectiveness of CFNB in this setting: quality of analgesia was similar, with no reduction in either local anesthetic or morphine consumption, and equivalent postoperative quadriceps weakness.

TRIAL REGISTRATION

Retrospectively registered at ( NCT03376178 ). Date: 21 November 2017.

Pediatric Ambulatory Continuous Peripheral Nerve Blocks

Despite the widespread use of ambulatory continuous peripheral nerve blocks in adults, its use in children has been sporadic. Indications for the use of ambulatory continuous peripheral nerve block in children involve orthopedic procedure, where significant pain is anticipated beyond 24 hours. Techniques to place the perineural catheters in children are similar to that used in adults. The incidence of serious side effects in pediatric ambulatory continuous peripheral nerve block is extremely rare. When this is combined with the potential to increase patient and family satisfaction and decrease opioid-related side effects, ambulatory continuous peripheral nerve block become a compelling choice.

A Summary of the Anatomy and Current Regional Anesthesia Practices for Postoperative Pain Management in Total Knee Arthroplasty

The planning and implementation of an effective postoperative pain management program depend on the surgical technique for total knee arthroplasty (TKA), the type of regional anesthesia, and the multimodal analgesia regimen. It is imperative to understand the surgical anatomy of TKA and the relevant nerve supply of the knee for optimum perioperative patient satisfaction with respect to pain management in the patient undergoing TKA. The commonly used regional techniques have their own specific benefits and limitations. The ideal postoperative pain management should be customized for a patient to achieve the goals of effective pain control, early ambulation, faster recovery, and discharge.

A comparison of two different concentrations and infusion rates of ropivacaine in perineural infusion administered at the same total dose for analgesia after foot and ankle surgery: a randomized, double blinded, controlled study

BACKGROUND

Continuous popliteal nerve block is utilized for postoperative analgesia after foot and ankle surgery. Whether only the total dose of local anesthetic or the combination of concentration and volume determine the characteristics of a continuous popliteal nerve infusion remains currently unknown. We hypothesized a reduction of the incidence of insensate extremity in patients given ropivacaine 0.4% at 4 mL/h compared to patients given ropivacaine 0.2% at 8 mL/h.

METHODS

Sixty-four patients scheduled for major foot and ankle surgery requiring a continuous popliteal catheter infusion for postoperative analgesia were studied. Thirty-three patients were randomized to receive a continuous popliteal nerve block with 0.2% (basal 8 mL/h) and thirty-one with 0.4% (basal 4 mL/h) ropivacaine, reaching the same total dose (16 mg/h). The primary outcome was the incidence of persistent sensory block in the distal sciatic nerve distributions in the postoperative period. Secondary outcomes were the incidence of motor block, NRS pain scores at rest in the postoperative period up to 48 hours after surgery, opioid use and related side effects, patients' satisfaction.

RESULTS

The incidence of persistent sensory block was similar in patients given 0.2% and in patients receiving 0.4% ropivacaine. The incidence of motor block, postoperative pain scores at rest, use of oral opioids, side effects and patients' satisfaction with the quality of recovery were also similar in both groups.

CONCLUSIONS

Our results suggest that local anesthetic total dose is the primary determinant of continuous popliteal perineural infusion effects.

Analgesic Efficacy of Adductor Canal Block in Total Knee Arthroplasty: A Meta-analysis and Systematic Review

The aim of this meta‐analysis and systematic review of randomized controlled trials (RCTs) was to evaluate the efficacy and safety of adductor canal block (ACB) for early postoperative pain management in patients undergoing total knee arthroplasty (TKA). Relevant manuscripts comparing ACB with saline or femoral nerve block (FNB) in TKA patients were searched for in the databases of PubMed, EMBASE, and Cochrane library. The outcomes assessed included cumulative analgesic consumption, pain at rest or during movement, ability to ambulate, quadriceps strength, and complications (nausea, vomiting or sedation). For continuous outcomes, pooled effects were measured using weighted mean difference (WMD) or standard mean difference (SMD), together with 95% confidence intervals (CIs). For outcomes without sufficient data for synthesis, qualitative interpretation of individual studies was summarized. Finally, 11 RCTs involving 675 patients met the inclusion criteria. The pooled results showed that ACB resulted in less postoperative analgesic consumption than saline (WMD, −12.84 mg; 95% CI, −19.40 mg to −6.27 mg; P < 0.001) and less pain at rest or during activity. No conclusions could be drawn regarding ability to ambulate and quadriceps strength, because only one study reported these variables. Most studies comparing ACB and FNB reported similar effects on postoperative analgesic consumption (WMD, −0.56 mg; 95% CI, −8.05 mg to 6.93 mg; P = 0.884) and pain; however, ability to ambulate and quadriceps strength were significantly better with ACB (SMD, 0.99; 95% CI, 0.04–1.94; P = 0.041). Additionally, ACB did not increase the rate of complications. Our results suggest that, compared with saline, ACB decreases analgesic consumption and offers short‐term advantages in terms of pain relief. Compared with FNB, ACB was associated with better ability to ambulate and quadriceps strength.

Novel Regional Techniques for Total Knee Arthroplasty Promote Reduced Hospital Length of Stay: An Analysis of 106 Patients

BACKGROUND

Novel regional techniques, including the adductor canal block (ACB) and the local anesthetic infiltration between the popliteal artery and capsule of the knee (IPACK) block, provide an alternative approach for controlling pain following total knee arthroplasty (TKA). This study compared 3 regional techniques (femoral nerve catheter [FNC] block alone, FNC block with IPACK, and ACB with IPACK) on pain scores, opioid consumption, performance during physical therapy, and hospital length of stay in patients undergoing TKA.

METHODS

All patients had a continuous perineural infusion, either FNC block or ACB. Patients in the IPACK block groups also received a single injection 30-mL IPACK block of 0.25% ropivacaine. Pain scores and opioid consumption were recorded at postanesthesia care unit discharge and again at 8-hour intervals for 48 hours. Physical therapy performance was measured on postoperative days (POD) 1 and 2, and hospital length of stay was recorded.

RESULTS

We found no significant differences in the 3 groups with regard to baseline patient demographics. Although we observed no differences in pain scores between the 3 groups, opioid consumption was significantly reduced in the FNC with IPACK group. Physical therapy performance was significantly better on POD 1 in the ACB with IPACK group compared to the other 2 groups. Hospital length of stay was significantly shorter in the ACB with IPACK group.

CONCLUSION

This study demonstrated that an IPACK block reduced opioid consumption by providing effective supplemental analgesia following TKA compared to the FNC-only technique. ACB with IPACK provided equivalent analgesia and improved physical therapy performance, allowing earlier hospital discharge.

Patient-controlled bolus femoral nerve block after knee arthroplasty: quadriceps recovery, analgesia, local anesthetic consumption

BACKGROUND

Continuous femoral nerve block (cFNB) induces quadriceps muscle weakness, but patient-controlled femoral nerve block (PCFNB) can provide analgesia with lower consumption of local anesthetics compared to cFNB. We hypothesized that cFNB followed by PCFNB leads to accelerated recovery of quadriceps weakness after total knee arthroplasty compared to cFNB alone. Secondary outcomes were local anesthetic consumption, pain, and mobilization.

METHODS

Fifty-six subjects received post-operative cFNB for 24 h and then randomized to receive either cFNB (basal infusion of 6 ml/h using a dummy bolus button; n = 27) or PCFNB (bolus infusion of 3 ml with a lockout time of 30 min and no basal infusion; n = 29) using 0.08% levobupivacaine for the subsequent 24 h in a double-blind manner (registration: UMIN000010105). Quadriceps strength was assessed using a hand-held dynamometer. The percentage change from baseline was compared between groups.

RESULTS

Quadriceps strength at 48 h was 47.3 ± 18.3% in the cFNB group and 49.7 ± 15.7% in the PCFNB group (95% confidence interval -7.0-11.9%, P = 0.61). Local anesthetic consumption during the post-operative period was significantly lower in the PCFNB group compared to the cFNB group (102 ± 10.8 ml vs.146 ± 4.6 ml; P < 0.001). No significant differences were found in any of the other outcomes, including pain scores at rest and during knee rehabilitation.

CONCLUSION

Continuous femoral nerve block followed by PCFNB does not improve quadriceps strength recovery time compared to cFNB alone after total knee arthroplasty, but similar analgesic effects were demonstrated with reduced levobupivacaine consumption.

Continuous intra-articular local anesthetic drug instillation versus discontinuous sciatic nerve block after total knee arthroplasty

STUDY OBJECTIVE

Sciatic nerve block (SNB) is commonly used as adjunct to femoralis nerve block (FNB) to achieve high-quality pain relief after total knee arthroplasty (TKA). However, this combination is associated with considerable muscle weakness, foot drop and surgically related nerve injuries may be masked. The purpose of this study was to assess whether low risk continuous intra-articular anesthetic drug instillation is an adequate alternative to SNB when adding to FNB after TKA.

DESIGN

Retrospective investigational follow-up study.

SETTING

University teaching hospital. Interdisciplinary postoperative anesthetic and orthopedic survey.

PATIENTS

For this investigational analysis, 34 of 50 consecutive patients were available.

INTERVENTIONS

All patients underwent primary unilateral TKA. Group A (18 patients) received a continuous intra-articular 0.33% ropivacaine (5 mL/h) instillation for the first 48 h postoperatively. In Group B (16 patients) a discontinuous SNB was used. Both groups were treated with a continuous FNB.

MEASUREMENTS

Main endpoints were mean and maximum postoperative pain intensity levels for both anterior and posterior knee side, amount of postoperative administered opioid drugs, differences in functional outcome or hospital stay and rate of postoperative complications.

MAIN RESULTS

Group A showed higher pain intensity levels for the posterior knee side (P≤.042). Merely on the second postoperative day there were no differences within either study group. No differences were found regarding anterior knee pain. Group A showed a significant higher postoperative piritramid consumption (P≤.007). Length of hospital stay or postoperative functional outcome was not significant different. Postoperative complications were not related to anesthesia techniques.

CONCLUSIONS

SNB technique resulted in superior pain relief in comparison to continuous intra-articular local anesthetic drug instillation as adjunct to continuous FNB after TKA.

Peripheral Nerve Blocks Causing Increased Risk for Fall and Difficulty in Ambulation for the Hip and Knee Joint Replacement Patient

A systematic review of the literature was completed by the Evidence-Based Practice Group for the Patient population, Intervention/Issue, Comparison Intervention, Outcomes, Timing (PICOT) question: "Does the use of a peripheral nerve block increase the risk for falls and difficulty ambulation in patients after lower extremity surgery through postoperative day 2?" A search of multiple databases using specified key terms resulted in 258 articles for total knee arthroplasty or total hip arthroplasty. These were reduced to 13 with exclusion criteria and became primary evidence. Numbers Needed to Harm and Numbers Needed to Treat (NNT) were calculated. Numbers Needed to Harm supported the PICOT question. Further research of postoperative falls and nursing interventions to reduce or prevent falls is suggested before creation of a Clinical Practice Guideline.

The Isolated Effect of Adductor Canal Block on Quadriceps Femoris Muscle Strength After Total Knee Arthroplasty: A Triple-Blinded, Randomized, Placebo-Controlled Trial with Individual Patient Analysis

BACKGROUND

Using peripheral nerve block after total knee arthroplasty (TKA), without impeding mobility, is challenging. We hypothesized that the analgesic effect of adductor canal block (ACB) could increase the maximum voluntary isometric contraction (MVIC) of the quadriceps femoris muscle after TKA.

METHODS

We included 64 patients on the first postoperative day. Group A received an ACB with 30 mL ropivacaine 0.75% at t0 and with 30 mL saline 60 minutes later (t60). Group B received the treatment in the opposite order. The primary end point was the difference between groups in MVIC at t60, expressed as a percentage of postoperative preblock values. In this manner, the effect of the ACB could be isolated from the detrimental effect on muscle strength caused by the surgery. Secondary end points were differences between groups in mobility and pain scores. We planned a subgroup analysis dividing patients according to preblock pain scores during knee flexion.

RESULTS

At t60, MVIC was higher in group A, with a median of 170% (95% confidence interval [CI], 147-231) of preblock values compared with 93% (95% CI, 82-98) in group B (P < 0.0001). No statistically significant differences were found in the Timed Up and Go (TUG) test. Three patients lost the ability to perform the TUG test in group A. At t60, differences in visual analog scale pain were in favor of group A; 12 mm (95% CI, 6-18) at rest, 14 mm (95% CI, 5-22) during knee flexion, and 18 mm (95% CI, 10-26) during the TUG test.

CONCLUSIONS

ACB improves quadriceps femoris muscle strength, but whether this translates into enhanced mobility is not clearly supported by this study.

Factors Related to Postoperative Pain Trajectories following Total Knee Arthroplasty: A Longitudinal Study of Patients Admitted to a Russian Orthopaedic Clinic

This study explores sociodemographic, clinical, and surgical factors in relation to pain trajectories during the first 3 days following total knee arthroplasty (TKA). 100 patients (mean age 63.5 ± 7.8 years and 93% female) consecutively admitted for uncomplicated primary TKA were prospectively included. Postoperative pain was assessed using pain diaries. Measures of preoperative pain, symptoms, daily functioning, quality of life, comorbidities, knee function, perioperative characteristics, and physical/biochemical parameters were also evaluated. All pain ratings decreased in the three days following surgery (p < .001) as well as the reported number of daily hours in moderate/severe pain (p < .001). Women reported more pain than men (p = .009). Pain trajectories did not differ by education, employment, cohabitation, or any patient clinical and biochemical characteristics but were significantly related to preoperative anxiety (p = .029). Patients reporting moderate/severe pain prior to surgery also reported more hours in moderate/severe pain on days 0–3 postoperatively (p = .029). Patients with surgeries longer than 90 min reported more hours of moderate/severe pain compared with patients who had shorter surgeries (p = .008), and similar results were observed for ratings of pain with activity (p = .012). In this sample, only female gender, higher levels of preoperative pain and anxiety, and longer surgical duration were associated with increased pain after TKA.

Readmission and Complications for Catheter and Injection Femoral Nerve Block Administration After Total Knee Arthroplasty in the Medicare Population

There is general agreement that femoral nerve blocks (FNB) provide adequate immediate postoperative analgesia after total knee arthroplasty (TKA), although the effect of this technique on hospital readmission and other complications has not been quantified in a large sample. The Medicare 5% sample was used to identify TKA patients who were grouped according to postoperative FNB administration: FNB via injection; FNB via pain pump; and no FNB. Multivariate Cox regressions were used to evaluate risk factors for the postoperative outcomes. Both FNB groups were associated with a lower risk of readmission (30, 90 and 365 days, P<0.001). Future clinical studies may help elucidate whether the lower hospital readmissions may be associated with more effective pain control with the use of FNB.

Discharge Readiness after Tricompartment Knee Arthroplasty

Background:

The authors conducted a randomized, controlled, parallel-arm, superiority study to test the hypothesis that a continuous adductor canal block decreases the time to attain four discharge criteria compared with a continuous femoral nerve block after tricompartment knee arthroplasty.

Methods:

Subjects undergoing tricompartment knee arthroplasty were randomized using computer-generated lists to either an adductor canal or femoral perineural catheter (3-day ropivacaine 0.2% infusion) in an unmasked manner. The primary outcome was the time to attain four criteria: (1) adequate analgesia; (2) intravenous opioids independence; (3) ability to stand, walk 3 m, return, and sit down; and (4) ambulate 30 m.

Results:

Subjects with an adductor canal catheter (n = 39) reached all four criteria in a median of 55 h (interquartile, 42 to 63 h) compared with 61 h (49 to 69 h) for those with a femoral catheter (n = 41; 95% CI, −13 to 1 h; P = 0.12). The percentage of subjects who reached the two mobilization criteria on postoperative days 1 and 2 were 72 and 95% for those with an adductor canal catheter (n = 39), but only 27 and 76% in subjects with a femoral catheter (n = 41; both P &lt; 0.001). Differences in pain scores at rest and intravenous opioid requirements were minimal, but femoral infusion improved dynamic analgesia (P = 0.01 to 0.02).

Conclusion:

Compared with a continuous femoral nerve block, a continuous adductor canal block did not appreciably decrease the time to overall discharge readiness even though it did decrease the time until adequate mobilization, primarily because both groups experienced similar analgesia and intravenous opioid requirements that—in most cases—exceeded the time to mobilization.

Developing a multidisciplinary fall reduction program for lower-extremity joint arthroplasty patients

With the anticipated increase in the number of total joint arthroplasty surgeries and associated fall risks, a fall reduction program can provide greater safety for patients in the postoperative period. Although further prospective studies are needed among total joint arthroplasty patients, there is sufficient evidence to show that a successful fall reduction program can be implemented. Common components to date have included a multidisciplinary team, multicomponent interventions specific to the risks associated with total knee and hip arthroplasty patients, education of patients and staff, and strategies to promote adherence to the program.

A randomized, triple-masked, active-controlled investigation of the relative effects of dose, concentration, and infusion rate for continuous popliteal-sciatic nerve blocks in volunteers

BACKGROUND

It remains unknown whether local anaesthetic dose is the only factor influencing continuous popliteal-sciatic nerve block effects, or whether concentration, volume, or both exert an influence as well.

METHODS

Bilateral sciatic catheters were inserted in volunteers (n=24). Catheters were randomly assigned to ropivacaine of either 0.1% (8 ml h(-1)) or 0.4% (2 ml h(-1)) for 6 h. The primary endpoint was the tolerance to transcutaneous electrical stimulation within the tibial nerve distribution at hour 6. Secondary endpoints included current tolerance at other time points and plantar flexion maximum voluntary isometric contraction (22 h total).

RESULTS

At hour 6, tolerance to cutaneous stimulation for limbs receiving 0.1% ropivacaine was [mean (standard deviation)] 27.0 (20.2) vs26.9 (20.4) mA for limbs receiving 0.4% [estimated mean difference 0.2 mA; 90% confidence interval (CI) -8.2 to 8.5; P=0.02 and 0.03 for lower and upper boundaries, respectively]. Because the 90% CI fell within the prespecified tolerance ±10 mA, we conclude that the effect of the two concentration/volume combinations were equivalent. Similar negative findings were found for the secondary outcomes.

CONCLUSIONS

For continuous popliteal-sciatic nerve blocks, we found no evidence that local anaesthetic concentration and volume influence block characteristics, suggesting that local anaesthetic dose (mass) is the primary determinant of perineural infusion effects in this anatomic location. These findings suggest that for ambulatory perineural local anaesthetic infusion-for which there is usually a finite local anaesthetic reservoir-decreasing the basal rate while increasing the local anaesthetic concentration may allow for increased infusion duration without compromising postoperative analgesia.

CLINICAL TRIAL REGISTRATION

NCT01898689.

Adductor canal block versus femoral nerve block for analgesia after total knee arthroplasty: a randomized, double-blind study

BACKGROUND AND OBJECTIVES

Femoral nerve block (FNB), a commonly used postoperative pain treatment after total knee arthroplasty (TKA), reduces quadriceps muscle strength essential for mobilization. In contrast, adductor canal block (ACB) is predominately a sensory nerve block. We hypothesized that ACB preserves quadriceps muscle strength as compared with FNB (primary end point) in patients after TKA. Secondary end points were effects on morphine consumption, pain, adductor muscle strength, morphine-related complications, and mobilization ability.

METHODS

We performed a double-blind, randomized, controlled study of patients scheduled for TKA with spinal anesthesia. The patients were randomized to receive either a continuous ACB or an FNB via a catheter (30-mL 0.5% ropivacaine given initially, followed by a continuous infusion of 0.2% ropivacaine, 8 mL/h for 24 hours). Muscle strength was assessed with a handheld dynamometer, and we used the percentile change from baseline for comparisons. The trial was registered at clinicaltrials.gov (Identifier: NCT01470391).

RESULTS

We enrolled 54 patients, of which 48 were analyzed. Quadriceps strength as a percentage of baseline was significantly higher in the ACB group compared with the FNB group: (median [range]) 52% [31-71] versus 18% [4-48], (95% confidence interval, 8-41; P = 0.004). There was no difference between the groups regarding morphine consumption (P = 0.94), pain at rest (P = 0.21), pain during flexion of the knee (P = 0.16), or adductor muscle strength (P = 0.39); neither was there a difference in morphine-related adverse effects or mobilization ability (P > 0.05).

CONCLUSIONS

Adductor canal block preserved quadriceps muscle strength better than FNB, without a significant difference in postoperative pain.

Adductor Canal Block versus Femoral Nerve Block for Total Knee Arthroplasty

Background:

This prospective double-blinded, randomized controlled trial compared adductor canal block (ACB) with femoral nerve block (FNB) in patients undergoing total knee arthroplasty. The authors hypothesized that ACB, compared with FNB, would exhibit less quadriceps weakness and demonstrate noninferior pain score and opioid consumption at 6 to 8 h postanesthesia.

Methods:

Patients received an ACB or FNB as a component of a multimodal analgesic. Quadriceps strength, pain score, and opioid consumption were assessed on both legs preoperatively and at 6 to 8, 24, and 48 h postanesthesia administration. In a joint hypothesis test, noninferiority was first evaluated on the primary outcomes of strength, pain score, and opioid consumption at 6 to 8 h; superiority on each outcome at 6 to 8 h was then assessed only if noninferiority was established.

Results:

Forty-six patients received ACB; 47 patients received FNB. At 6 to 8 h postanesthesia, ACB patients had significantly higher median dynamometer readings versus FNB patients (median [interquartile range], 6.1 kgf [3.5, 10.9] (ACB) vs. 0 kgf [0.0, 3.9] (FNB); P &lt; 0.0001), but was not inferior to FNB with regard to Numeric Rating Scale pain scores (1.0 [0.0, 3.5] ACB vs. 0.0 [0.0, 1.0] FNB; P = 0.019), or to opioid consumption (32.2 [22.4, 47.5] ACB vs. 26.6 [19.6, 49.0]; P = 0.0115). At 24 and 48 h postanesthesia, there was no significant statistical difference in dynamometer results, pain scores, or opioid use between the two groups.

Conclusion:

At 6 to 8 h postanesthesia, the ACB, compared with the FNB, exhibited early relative sparing of quadriceps strength and was not inferior in both providing analgesia or opioid intake.

Adductor Canal Block versus Femoral Nerve Block and Quadriceps Strength

Background:

The authors hypothesized that the adductor canal block (ACB), a predominant sensory blockade, reduces quadriceps strength compared with placebo (primary endpoint, area under the curve, 0.5–6 h), but less than the femoral nerve block (FNB; secondary endpoint). Other secondary endpoints were adductor strength and ability to ambulate.

Methods:

The authors enrolled healthy young men into this double blind, placebo-controlled, randomized, crossover study. On two separate study days, subjects received either ACB or FNB with ropivacaine, and placebo in the opposite limb. Strength was assessed as maximum voluntary isometric contraction for quadriceps and adductor muscles. In addition, subjects performed three standardized ambulation tests. Clinicaltrials.gov Identifier: NCT01449097.

Results:

Twelve subjects were randomized, 11 analyzed. Quadriceps strength (area under the curve, 0.5–6 h) was significantly reduced when comparing ACB with placebo (5.0 ± 1.0 vs. 5.9 ± 0.6, P = 0.02, CI: −1.5 to −0.2), FNB with placebo (P = 0.0004), and when comparing FNB with ACB (P = 0.002). The mean reduction from baseline was 8% with ACB and 49% with FNB. The only statistically significant difference in adductor strength was between placebo and FNB (P = 0.007). Performance in all mobilization tests was reduced after an FNB compared with an ACB (P &lt; 0.05).

Conclusions:

As compared with placebo ACB statistically significantly reduced quadriceps strength, but the reduction was only 8% from baseline. ACB preserved quadriceps strength and ability to ambulate better than FNB did. Future studies are needed to compare the analgesic effect of the ACB with the FNB in a clinical setting.

Continuous femoral nerve blocks: the impact of catheter tip location relative to the femoral nerve (anterior versus posterior) on quadriceps weakness and cutaneous sensory block

BACKGROUND

During a continuous femoral nerve block, the influence of catheter tip position relative to the femoral nerve on infusion characteristics remains unknown.

METHODS

We inserted bilateral femoral perineural catheters in volunteers (ultrasound-guided, needle in-plane). Subjects' dominant side was randomized to have the catheter tip placed either anterior or posterior to the femoral nerve. The contralateral limb received the alternative position. Ropivacaine 0.1% was administered through both catheters concurrently for 6 hours (4 mL/h). Outcome measures included the maximum voluntary isometric contraction (MVIC) of the quadriceps femoris muscle and tolerance to cutaneous electrical current over to the distal quadriceps tendon. Measurements were performed at hour 0 (baseline), and on the hour until hour 9, as well as hour 22. The primary end point was the MVIC of the quadriceps at hour 6.

RESULTS

As a percentage of the baseline measurement, quadriceps MVIC for limbs with anterior (n = 16) and posterior (n = 16) catheter tip placement did not differ to a statistically significant degree at hour 6 (mean [SD] 29% [26] vs 30% [28], respectively; 95% confidence interval: -22% to 20%; P = 0.931), or at any other time point. However, the maximum tolerance to cutaneous electrical current was higher in limbs with anterior compared with posterior catheter tip placement at hour 6 (20 [23] mA vs 6 [4] mA, respectively; 95% confidence interval: 1-27 mA; P = 0.035), as well as at hours 1, 7, 8, and 9 (P < 0.04).

CONCLUSIONS

This study documents the significant (70%-80%) quadriceps femoris weakness induced by a continuous femoral nerve block infusion at a relatively low dose of ropivacaine (4 mg/h) delivered through a perineural catheter located both anterior and posterior to the femoral nerve. In contrast, an anterior placement increases cutaneous sensory block compared with a posterior insertion, without a concurrent relative increase in motor block.