The Optimal Analgesic Block for Total Knee Arthroplasty:

Efficacy of adductor canal and popliteal plexus block combined with local anesthetic injection in the interspace between the popliteal artery and posterior capsule of the knee and local infiltrative analgesia for postoperative pain and functional outcome after total knee arthroplasty: A randomized controlled study

BACKGROUND

Adductor canal block and periarticular infiltration analgesia (PIA) have been shown to relieve pain in total knee arthroplasty (TKA) effectively. However, their analgesic effectiveness has some limitations. Thus, we considered a novel blocking site that could achieve analgesia without affecting the muscle strength of the lower limbs.

METHODS

Seventy-two patients undergoing primary unilateral total knee arthroplasty were randomized into two groups. One group was treated with adductor canal and popliteal plexus (APB) combined with interspace between the popliteal artery and posterior capsule of the knee (iPACK) and local infiltration anesthesia (LIA) and the other was treated with PIA. The primary outcomes included postoperative pain, as assessed by the visual analog scale (VAS), and the consumption of oral tramadol. Secondary outcomes included functional recovery and daily ambulation distance. Tertiary outcomes included postoperative adverse effects.

RESULTS

The APB group had lower VAS scores after surgery at rest and during motion. Compared with the PIA group, the walking distance of the APB group on the second day was greater. The muscle strength of the APB group was lower than that of the PIA group at the early stage. Patients in the APB group also consumed less tramadol than those in the PIA group. There was no difference in the incidence of adverse events between the two groups.

CONCLUSIONS

APB combined with iPACK and LIA is a novel block for TKA, and it can reduce postoperative pain sooner after TKA without affecting postoperative functional recovery or increasing complications.

Comparison of Analgesic Effects of Continuous Femoral Nerve Block, Femoral Triangle Block, and Adductor Block After Total Knee Arthroplasty: A Randomized Clinical Trial

OBJECTIVES

This study aimed to compare the analgesic effects of continuous femoral nerve block (FNB), femoral triangle block (FTB), and adductor canal block (ACB) following total knee arthroplasty (TKA). The goal was to identify the most effective nerve block technique among these.

METHODS

Patients undergoing TKA were randomly assigned to 1 of 3 groups: FNB, FTB, or ACB. Nerve blocks were administered preoperatively, with catheters placed for patient-controlled nerve analgesia (PCNA). The primary end point was the Numeric Rating Scale (NRS) score at movement at 24 hours postsurgery. Secondary end points included NRS scores at rest and movement, quadriceps strength, Timed Up and Go (TUG) test performance, range of motion, effective PCNA utilization, and opioid consumption at various postsurgery time points.

RESULTS

Of the 94 valid data sets analyzed (FNB: 31, FTB: 31, ACB: 32), significant differences were observed in the primary end point (H=7.003, P =0.03). Post hoc analysis with Bonferroni correction showed that the FNB group had a significantly lower median pain score (3 [2 to 4]) compared with the ACB group (4 [3 to 5], Bonferroni-adjusted P =0.03). Regarding secondary end points, both the FNB and FTB groups had significantly lower NRS scores than the ACB group at various time points after surgery. Quadriceps strength and TUG completion were better in the FTB and ACB groups. There were no statistically significant differences among the groups for the other end points.

DISCUSSION

Continuous FTB provides postoperative analgesia comparable to FNB but with the advantage of significantly less impact on quadriceps muscle strength, a benefit not seen with FNB. Both FTB and ACB are effective in preserving quadriceps strength postoperatively.

[Old and New Regional Anesthesia Procedures Under Review - Abdomen to Toe]

Ultrasound (US) technology has significantly expanded the spectrum of regional anesthesiological procedures in recent years. Abdominal wall blocks are becoming an increasingly integral part of a multimodal postoperative pain concept after abdominal surgery, gynecological or urological interventions. Thoracic epidural analgesia remains the gold standard for extensive surgery. The requirement for rapid postoperative mobilization and discharge after lower extremity surgery has led to the abandonment of neuroaxial or plexus blocks in favor of selective, peripheral blocks such as the PENG block or adductor canal block. The following article is intended to show the reader the change in the use of regional anesthesiological procedures for abdominal wall and lower extremity blocks using selected blockages.

Femoral-Obturator-Sciatic (FOS) Nerve Block as an Anesthetic Triad for Arthroscopic ACL Reconstruction: Is This the Magic Trick We Were Missing?

Arthroscopic anterior cruciate ligament (ACL) reconstruction with hamstring grafting is a common orthopedic procedure that is associated with moderate-to-severe pain. Peripheral nerve blockade as an anesthetic technique is an appealing option in the era of modern anesthesia. The aim of this narrative review is to document the efficacy and safety of the combination of femoral, obturator, and sciatic (FOS) nerve blocks as an exclusive method for anesthesia in patients undergoing ACL reconstruction. An electronic search of the literature published up to October 2023 was conducted in the Medline, Embase, Cochrane, Web of Science, and Google Scholar databases to find studies on ACL reconstruction and peripheral obturator nerve block. Overall, 8 prospective studies-with a total of 315 patients-published between 2007 and 2022 were included in this review. Ultrasound-guided peripheral FOS nerve blockade is an effective anesthetic technique for ACL reconstruction, offering good perioperative pain management, minimal opioid consumption, and an excellent safety profile. Further well-designed prospective studies are needed to determine the best approach for obturator nerve blockade and the appropriate type and dosage of local anesthetic.

Distal subsartorial compartment block of the saphenous nerve - A dissection study and a patient case series

STUDY OBJECTIVE

A saphenous nerve block is an important tool for analgesia after foot and ankle surgery. The conventional midthigh approach to saphenous nerve block in the femoral triangle may impede ambulation by impairing quadriceps motor function.

PRIMARY OBJECTIVE

Developing a selective saphenous nerve block targeting the nerve distal to its emergence from the adductor canal in the subsartorial compartment.

DESIGN

This study consists of A) a dissection study and B) Data from a clinical case series.

SETTING

A) Medical University of Innsbruck, Austria (dissection of 15 cadaver sides) and. B) Aarhus University Hospital, Denmark (5 patients).

INTERVENTIONS

A) Five mL of methylene blue was injected into the subsartorial compartment distal to the intersection of the saphenous nerve and the tendon of the adductor magnus guided by ultrasound. B) Five patients undergoing major hindfoot and ankle surgery had a subsartorial compartment block with 10 mL of local anesthetic in addition to a popliteal sciatic nerve block.

MEASUREMENT

A) The frequencies of staining the saphenous and medial vastus nerves. B) Assessment of postoperative pain by NRS score (0-10) and success rate of saphenous nerve block by presence of cutaneous anesthesia in the anteromedial lower leg, and motor impairment by ability to ambulate.

MAIN RESULTS

A) The saphenous nerve was stained in 15/15 cadaver sides. A terminal branch of the medial vastus nerve was stained in 2/15 cadaver sides. B) All patients were fully able to ambulate without support. No patients had any post-surgical pain from the anteromedial aspect of the ankle and foot (NRS score 0). The success rate of saphenous nerve block was 100%.

CONCLUSION

The saphenous nerve can be targeted in the subsartorial compartment distal to the intersection of the nerve and the tendon of the adductor magnus. The subsartorial compartment block provided efficient analgesia without quadriceps motor impairment.

Retrospective Analysis of Ultrasound-Guided Serial-Injection Triple Nerve Block Efficacy in Cementless Bipolar Hemiarthroplasty for Femoral Neck Fracture

BACKGROUND

Femoral neck fractures are effectively treated with bipolar hemiarthroplasty (BHA) surgery, yet postoperative pain management remains a challenge. This study explores the efficacy of multimodal pain management in minimizing opioid use and enhancing recovery.

METHODS

A retrospective analysis of 87 patients who underwent BHA between September 2016 and September 2020 was conducted. Patients were analyzed in two groups: Group I (n = 42), receiving serial-injection nerve blocks (SINBs) before and after surgery, and Group II (n = 41), with no SINB. Notably, all nerve blocks for Group I were performed after November 2017, following the implementation of this technique in our protocol. Pain and analgesic medication usage were assessed over 72 h post-surgery, along with hospitalization duration and perioperative complications.

RESULTS

Group I patients exhibited significantly lower pain scores at 6, 12, 24, and 48 h post-surgery, alongside reduced incidences of postoperative nausea and vomiting (PONV) and delirium compared with Group II (p < 0.05).

CONCLUSIONS

Utilizing sequential lower limb nerve blocks under ultrasound guidance in BHA surgeries effectively reduces early postoperative pain and associated adverse effects. This approach demonstrates potential benefits in pain management, leading to diminished narcotic usage and lower risks of PONV and delirium.

Preoperative Femoral Nerve Block and Postoperative Sciatic Nerve Block at the Subgluteal Space After Total Knee Arthroplasty: A Retrospective Cohort Study

Background A preoperative sciatic nerve block (SNB) before total knee arthroplasty (TKA) frequently causes postoperative drop foot; however, this can also occur as an unintended result of surgical invasion. This study assessed the benefits of a postoperative SNB at the subgluteal space for patients who underwent TKA. Methodology This was a single-center, retrospective cohort study. Patients who underwent TKA under general anesthesia between May 2018 and June 2019 at the Teikyo University School of Medicine were screened for inclusion. They received either a preoperative femoral nerve block alone (control group; n = 87) or a preoperative femoral nerve block and postoperative SNB at the subgluteal space (post-SNB group; n = 40). The primary outcome was the pain-related Numerical Rating Scale (NRS) scores. The secondary outcomes were postoperative nausea and vomiting (PONV), intravenous patient-controlled analgesia (iv-PCA) suspension, and postoperative complications. Results No significant differences were observed in the characteristics, NRS scores, time to first drug use for pain, and iv-PCA suspension between groups. However, the incidence of PONV was significantly lower in the post-SNB group (p = 0.03). Logistic regression analysis revealed that droperidol doses of iv-PCA and the presence of postoperative SNB were independently associated with PONV occurrence [A1] {(p = 0.008, 95% confidence intervals (CI) [0.46, 0.89] and (p = 0.02, 95% CI [0.25, 0.88])}. Conclusions A postoperative SNB at the subgluteal space following TKA does not improve postoperative pain control; however, it may have contributed to reduced PONV.

Integrating IPACK (Interspace between the Popliteal Artery and Capsule of the Posterior Knee) Block in an Enhanced Recovery after Surgery Pathway for Total Knee Arthroplasty-A Prospective Triple-Blinded Randomized Controlled Trial

We explored the efficacy of an interspace between the popliteal artery and capsule of the posterior knee (IPACK) block when added to an established enhanced recovery after surgery (ERAS) pathway to assist with posterior knee analgesia and functional mobility after total knee arthroplasty (TKA). We recruited participants undergoing TKA in our prospective, randomized, triple-blinded controlled trial. All study patients participated in our ERAS pathway consisting of a primary spinal anesthetic, adductor canal nerve catheter, and periarticular joint infiltration. Patients were randomized to receive an IPACK block or no block. The primary outcome was total postoperative opioid consumption. Secondary outcomes included pain scores, recovery unit length of stay, time to first opioid use, the incidence of posterior knee pain, ambulation distance and activities of daily living on postoperative day 1, and hospital length of stay. A total of 96 patients were randomized to the control and IPACK groups. There were no statistical differences in primary or majority of secondary outcomes. There was a lower incidence of posterior knee pain (39%) in the IPACK group when compared with controls (8.7%), p < 0.01. In terms of opioid consumption and a majority of functional outcomes, our study demonstrates no overall benefits of adding an IPACK block in this ERAS pathway in TKA. Nevertheless, IPACK may have the potential of mitigating posterior knee pain after TKA.

LEVEL OF EVIDENCE

level 1.

CLINICAL TRIAL NUMBER AND REGISTRY URL

NCT03653416. www.

CLINICALTRIALS

gov.

Analgesic efficacy of selective tibial nerve block versus partial local infiltration analgesia for posterior pain after total knee arthroplasty: a randomized, controlled, triple-blinded trial

BACKGROUND

The adductor canal block provides pain relief on the anterior aspect of the knee after arthroplasty. Pain on the posterior aspect may be treated either by partial local infiltration analgesia of the posterior capsule or by a tibial nerve block. This randomized, controlled, triple-blinded trial tests the hypothesis that a tibial nerve block would provide superior analgesia compared to posterior capsule infiltration in patients scheduled for total knee arthroplasty under spinal anesthesia with an adductor canal block.

METHODS

Sixty patients were randomized to receive either infiltration of the posterior capsule by the surgeon with ropivacaine 0.2%, 25 mL, or a tibial nerve block with 10 mL of ropivacaine 0.5%. Sham injections were performed to guarantee proper blinding. The primary outcome was intravenous morphine consumption at 24 h. Secondary outcomes included intravenous morphine consumption, pain scores at rest and on movement, and different functional outcomes, measured at up to 48 h. When necessary, longitudinal analyses were performed with a mixed-effects linear model.

RESULTS

The median (interquartile range) of cumulative intravenous morphine consumption at 24 h was 12 mg (4-16) and 8 mg (2-14) in patients having the infiltration or the tibial nerve block respectively (p = 0.20). Our longitudinal model showed a significant interaction between group and time in favor of the tibial nerve block (p = 0.015). No significant differences were present between groups in the other above-mentioned secondary outcomes.

CONCLUSION

A tibial nerve block does not provide superior analgesia when compared to infiltration. However, a tibial nerve block might be associated with a slower increase in morphine consumption over time.

Migration rate of proximal adductor canal block catheters placed parallel versus perpendicular to the nerve after total knee arthroplasty: a randomized controlled study

BACKGROUND

Perineural catheters placed parallel to the nerve course are reported to have lower migration rates than those placed perpendicular to it. However, catheter migration rates for a continuous adductor canal block (ACB) remain unknown. This study compared postoperative migration rates of proximal ACB catheters placed parallel and perpendicular to the saphenous nerve.

METHODS

Seventy participants scheduled for unilateral primary total knee arthroplasty were randomly assigned for parallel or perpendicular placement of the ACB catheter. The primary outcome was the migration rate of the ACB catheter on postoperative day (POD) 2. Catheter migration was defined as being unable to confirm saline administration via the catheter around the saphenous nerve at the mid-thigh level under ultrasound guidance. Secondary outcomes included active and passive range of motion (ROM) of the knee on postoperative rehabilitation.

RESULTS

Sixty-seven participants were included in the final analyses. The catheter migrated significantly less often in the parallel group (5 of 34 (14.7%)) than in the perpendicular group (24 of 33 (72.7%)) (p<0.001). The mean (SD) active and passive knee flexion ROM (degrees) improved significantly in the parallel than in the perpendicular group (POD 1: active, 88.4 (13.2) vs 80.0 (12.4), p=0.011; passive, 95.6 (12.8) vs 85.7 (13.6), p=0.004; POD 2: active, 88.7 (13.4) vs 82.2 (11.5), p=0.036; passive, 97.2 (12.8) vs 91.0 (12.0), p=0.045).

CONCLUSION

Parallel placement of the ACB catheter provided a lower postoperative catheter migration rate than perpendicular placement of the ACB catheter along with corresponding improvements in ROM and secondary analgesic outcomes.

TRIAL REGISTRATION NUMBER

UMIN000045374.

Surgeon-placed peripheral nerve block and continuous non-opioid analgesia in total knee arthroplasty is accessible intraoperatively: A cadaveric study

BACKGROUND

Pain management in TKA patients is challenged by a postoperative requirement for early ambulation along with the concurrent goal of reducing opioid consumption while simultaneously reducing the length of hospital stay. Peripheral nerve blocks (PNB) address these concerns to some degree, with femoral nerve and adductor canal blocks being the most-used regional nerve blocks for surgeries performed around the knee joint.

PURPOSE

The authors hypothesized that placing a catheter between the muscles that make up the adductor canal during a standard surgical approach for a Total Knee Arthroplasty would provide equitable or superior access for a peripheral nerve block in the adductor canal. The nerves that are located between the muscles that make up the adductor canal transmit the majority of the pain after TKA.

METHODS

This cadaveric study was conducted in 12 fresh-frozen human cadaveric lower limbs, comparing the standard technique of adductor canal block, placed under ultrasound guidance, to this experimental technique. Using colored indicator dyes to locate the site of surrogate peripheral nerves, the techniques were compared.

RESULTS

Through a standard anterior surgical approach to the knee, an intraoperative catheter placement technique can be performed to provide a peripheral nerve block to the saphenous nerve for patients undergoing TKA that is comparable to standard ultrasound guided anesthesia block techniques.

CONCLUSIONS

This cadaveric study demonstrates the availability for the surgeon to place a catheter between the muscles that form the adductor canal during a standard surgical approach for TKA. This novel technique can provide equivalent coverage of the nerves for an ACB when compared to a standard ultrasound guided ACB.

Retrospective Analysis of Surgeon-Placed Nerve Block and Indwelling Catheter in the Adductor Canal in Total Knee Arthroplasty

INTRODUCTION

 Total knee arthroplasty (TKA) is now being performed in the outpatient setting, and often the postoperative pain is managed with opioid analgesics. Non-opioid pain management modalities are in crucial demand, and we propose a surgical technique that can potentially result in less pain and the decrease in the use of opioid analgesia following TKA. The purpose of this study was to investigate the safety and efficacy of a novel peripheral nerve block (PNB) that includes a single injection and catheter placement for a continuous regional nerve block in total knee arthroplasty.

METHODS

 Fifty-six patients underwent TKA by a single surgeon utilizing the novel method. Patient-reported outcomes were entered into an outcomes database and compared to an aggregate of over 3,500 comparative TKA patients. A visual analog scale (VAS) evaluated perioperative pain. Patient perioperative opioid usage, expectations of pain control, the incidence of common side effects, and the average hospital length of stay (LOS) were collected.

RESULTS

 Compared to the aggregate of patients in the database, the patients who received the novel surgeon-placed adductor canal block (ACB) and catheter placement reported findings that suggest this technique can possibly lead to a decrease in the severity of pain in addition to a reduction in side effects and the need for opioid analgesia. LOS for these patients was short, and patient satisfaction scores were excellent for the surgeon performing this technique.

CONCLUSIONS

Using the placement technique described, surgeons can reproducibly perform a single injection of PNB and place an indwelling catheter in the adductor canal through direct visualization of the muscles that make up the borders of the adductor canal. This technique offers potential advantages over pain management modalities that can be elucidated in further studies. The power of this study is limited due to these findings having not been analyzed for statistical significance.

Anatomical study of the adductor canal: three-dimensional micro-computed tomography, histological, and immunofluorescence findings relevant to neural blockade

BACKGROUND

A precise anatomical understanding of the adductor canal (AC) and its neural components is essential for discerning the action mechanism of the AC block. We therefore aimed to clarify the detailed anatomy of the AC using micro-computed tomography (micro-CT), histological evaluation, and immunofluorescence (IF) assays.

METHODS

Gross dissections of 39 thighs provided morphometric data relevant to injection landmarks. Serial sectional images of the AC were defined using micro-CT and ultrasonography. The fascial and neural structures of the AC proper were histologically evaluated using Masson's trichrome and Verhoeff-Van Gieson staining, and double IF staining using choline acetyltransferase (ChAT) and neurofilament 200 antibodies.

RESULTS

The posteromedial branch insertion of the nerve to vastus medialis (NVM) into the lateral border of the AC proper was lower (14.5 ± 2.4 cm [mean ± SD] above the base of the patella) than the origin of the proximal AC. The AC consists of a thin subsartorial fascia in the proximal region and a thick aponeurosis-like vastoadductor membrane in the distal region. In the proximal AC, the posteromedial branch of the NVM (pmNVM) consistently contained both sensory and motor fibers, and more ChAT-positive fibers were observed than in the saphenous nerve (27.5 ± 11.2 / 104 vs. 4.2 ± 2.6 / 104 [counts/µm2], P < 0.001).

CONCLUSIONS

Anatomical differences in fascial structures between the proximal and distal AC and a mixed neural component of the neighboring pmNVM have been visualized using micro-CT images, histological evaluation, and IF assays.

Pro and Con: How Important Is the Exact Location of Adductor Canal and Femoral Triangle Blocks?

In this Pro-Con commentary article, we debate the importance of anterior thigh block locations for analgesia following total knee arthroplasty. The debate is based on the current literature, our understanding of the relevant anatomy, and a clinical perspective. We review the anatomy of the different fascial compartments, the course of different nerves with respect to the fascia, and the anatomy of the nerve supply to the knee joint. The Pro side of the debate supports the view that more distal block locations in the anterior thigh increase the risk of excluding the medial and intermediate cutaneous nerves of the thigh and the nerve to the vastus medialis, while increasing the risk of spread to the popliteal fossa, making distal femoral triangle block the preferred location. The Con side of the debate adopts the view that while the exact location of local anesthetic injection appears anatomically important, it has not been proven to be clinically relevant.

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.

Significantly earlier ambulation and reduced risk of near-falls with continuous infusion nerve blocks: a retrospective pilot study of adductor canal block compared to femoral nerve block in total knee arthroplasty

Background

Near-falls should be detected to prevent falls related to the earlier ambulation after Total knee arthroplasty (TKA). The quadriceps weakness with femoral nerve block (FNB) has led to a focus on adductor canal block (ACB). We purposed to examine the risk of falls and the earlier ambulation in each continuous infusion nerve block.

Methods

Continuous infusion nerve block (FNB or ACB) was performed until postoperative day (POD) 2 or 3. Pain levels and falls/near-falls with knee-buckling were monitored from POD 1 to POD 3. The score on the manual muscle test, MMT (0 to 5, 5 being normal), of the patients who could ambulate on POD 1, was investigated.

Results

A total of 73 TKA cases, 36 FNB and 37 ACB, met the inclusion criteria. No falls were noted. But episodes of near-falls with knee-buckling were witnessed in 14 (39%) cases in the FNB group and in 4 (11%) in the ACB group (p = 0.0068). In the ACB group, 81.1% of patients could ambulate with parallel bars on POD 1, while only 44.4% of FNB patients could do so (p = 0.0019). The quadriceps MMT values in the ACB group was 2.82, significantly higher than 1.97 in the FNB group (p = 0.0035). There were no significant differences in pain as measured with a numerical rating scale (NRS) and rescue analgesia through POD 3.

Conclusion

ACB was associated with significantly less knee-buckling and earlier ambulation post-TKA, with better quadriceps strength. Our study indicated the incidence of falls and near-falls with continuous infusion nerve blocks, and support the use of ACB to reduce the risk of falls after TKA. It is suggested that a certain number of the patients even with continuous ACB infusion should be considered with the effect of motor branch to prevent falls.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05735-6.

iPACK block (local anesthetic infiltration of the interspace between the popliteal artery and the posterior knee capsule) added to the adductor canal blocks versus the adductor canal blocks in the pain management after total knee arthroplasty: a systematic review and meta-analysis

Background

Several studies have suggested that the addition of iPACK block (the popliteal artery and the posterior knee capsule have been given interspace local anesthetic infiltration) might get better analgesia than adductor canal block (ACB) only after total knee arthroplasty (TKA). This paper compiles all available evidence on the effect of two analgesia regimens (ACB and iPACK + ACB) involving all sides.

Methods

We searched in eight major databases for all clinical trials discussing the effect of two analgesia regimens after TKA. Statistical analyses were conducted by Stata and RevMan Software. In addition, we performed GOSH analysis, subgroup analysis, meta-regression analysis to study the source of heterogeneity. Publication bias was checked using Egger’s test. Trim-and-fill analysis was applied in terms of sensitivity analysis of the results.

Results

There are fourteen eligible studies for our meta-analysis. There are significant differences between the two groups in VAS score at rest and with activity, and the VAS scores were lower in the ACB + iPACK Group (VAS scores at rest: 95%CI [− 0.96, − 0.53], P < 0.00001. VAS scores with activity: 95%CI [− 0.79, − 0.43], P < 0.00001). A differential was discovered to support the ACB + iPACK Group when comparing the two groups on postoperative cumulative morphine consumption (95%CI: [− 0.52, − 0.14], P: 0.0007). The patients in the group of ACB + iPACK performed better in the postoperative range of knee movement (95%CI: [5.18, 10.21], P < 0.00001) and walking distance (95%CI: [0.15, 0.41], P < 0.00001). There were significant differences between the patients in the ACB + iPACK Group and ACB Group on the TUG test of POD1 and POD2. We found that patients' hospital stays in the ACB + iPACK Group were significantly shorter than in the ACB Group (95%CI: [− 0.78, − 0.16], P: 0.003). No difference was found between the patients in the ACB + iPACK Group and ACB Group on postoperative quadriceps muscle strength and the incidence of PONV.

Conclusion

The addition of iPACK lowers postoperative VAS scores, cumulative morphine consumption, and hospital stays. Meanwhile, the addition of iPACK improves postoperative patients’ activity performance without extra side effects. iPACK combined with ACB proves to be a suitable pain management technique after TKA.

Review on Nerve Blocks Utilized for Perioperative Total Knee Arthroplasty Analgesia

Total Knee Arthroplasty (TKA) is an increasingly common procedure performed for advanced osteoarthritis. Optimal perioperative pain management strategies are critical for early mobilization and shorter hospital stays in TKA. Peripheral nerve blocks commonly used in TKA perioperative analgesia including individual and combined femoral, obturator, sciatic, lumbar plexus, and adductor canal nerve blocks. Overall, the safety profile varies depending on which block is utilized, but the current evidence suggests when optimally chosen and delivered, peripheral nerve blocks may provide a safe, effective option for perioperative analgesia. Determining optimal analgesic regimens for total knee arthroplasty is critical to improve postoperative pain, patient satisfaction, decreasing opioid usage, recovery times and functional outcomes, and as such, peripheral nerve blocks may represent a viable option to supplement analgesic requirements in the perioperative period.

The effect of continuous adductor canal block combined with distal interspace between the popliteal artery and capsule of the posterior knee block for total knee arthroplasty: a randomized, double-blind, controlled trial

BACKGROUND

The optimal analgesia for total knee arthroplasty (TKA) requires excellent analgesia while preserving muscle strength. This study aimed to determine the hypothesis that continuous adductor canal block (CACB) combined with the distal interspace between the popliteal artery and the posterior capsule of the knee (IPACK) block could effectively alleviate the pain of the posterior knee, decrease opioids consumption, and promote early recovery and discharge.

METHODS

Patients undergoing unilateral, primary TKA were allocated into group CACB+SHAM (receiving CACB plus sham block) or group CACB+IPACK (receiving CACB plus IPACK block). The primary outcome was cumulative opioid consumption. Secondary outcomes included the incidence of postoperative pain originated from the posterior knee, visual analogue scale (VAS) score, range of motion, ambulation distance, and satisfaction for pain management.

RESULTS

The incidence of moderate-severe pain of the posterior knee was lower in group CACB+IPACK than that of the group CACB+SHAM at 4 hours (17.1% vs. 42.8%; p = 0.019), 8 hours (11.4% vs. 45.7%; p = 0.001), and 24 hours (11.4% vs. 34.3%; p = 0.046) after TKA. The VAS scores of the posterior knee were lower in group CACB+IPACK than that of the group CACB+SHAM at 4 hours [2 (2) vs. 3 (2-4); p = 0.000], 8 hours [1 (1, 2) vs. 3 (2-4); p = 0.001], and 24 hours [1(0-2) vs. 2 (1-4); p = 0.002] after TKA. The overall VAS scores were lower in group CACB+IPACK than that of the group CACB+SHAM at 4 hours [3 (2, 3) vs. 3 (3, 4); p = 0.013] and 8 hours [2 (2, 3) vs. 3 (2-4); p = 0.032] at rest and 4 hours [3 (3, 4) vs. 4 (4, 5); p = 0.001], 8 hours [3 (2-4) vs. 4 (3-5); p = 0.000], 24 hours [2 (2, 3) vs. 3 (2-4); p = 0.001] during active flexion after TKA. The range of motion (59.11 ± 3.90 vs. 53.83 ± 5.86; p = 0.000) and ambulation distance (44.60 ± 4.87 vs. 40.83 ± 6.65; p = 0.009) were superior in group CACB+IPACK than that of the group CACB+SHAM in postoperative day 1. The satisfaction for pain management was higher in group CACB+IPACK than that of the group CACB+SHAM [9 (8, 9) vs. 8 (7-9); p = 0.024]. There was no difference in term of cumulative opioids consumption between group CACB+IPACK and group CACB+SHAM [120(84-135) vs. 120(75-135); p = 0.835].

CONCLUSION

The combination of CACB and distal IPACK block could decrease the incidences of moderate-severe posterior knee pain, improve the postoperative pain over the first 24 hours after TKA, as well as promoting recovery of motor function. However, the opioids consumption was not decreased by adding distal IPACK to CACB.

TRIAL REGISTRATION

This study was registered at Chinese Clinical Trial Registry ( ChiCTR2200059139 ; registration date: 26/04/2022; enrollment date: 16/11/2020; http://www.chictr.org.cn ).

Optimal location for continuous catheter analgesia among the femoral triangle, proximal, or distal adductor canal after total knee arthroplasty: a randomized double-blind controlled trial

Background

Pain management after total knee arthroplasty is essential to improve early mobilization, rehabilitation, and recovery. Continuous adductor canal (AC) block provides postoperative analgesia while preserving quadriceps strength. However, there have been inconsistencies regarding the optimal location for continuous catheter block. We compared continuous femoral triangle, proximal AC, and distal AC blocks for postoperative analgesia after total knee arthroplasty.

Methods

Patients undergoing unilateral total knee arthroplasty were randomly assigned to three groups: femoral triangle, proximal AC, or distal AC. The surgeon performed periarticular local anesthetic infiltration. After surgery, an ultrasound-guided perineural catheter insertion procedure was performed. The primary endpoint was pain scores at rest in the morning on the first postoperative day. Secondary endpoints included pain scores at rest and during activity at other time points, quadriceps strength, and opioid consumption.

Results

Ninety-five patients, 32 in the femoral triangle group, 31 in the proximal AC group, and 32 in the distal AC group, completed the study. Analysis of the primary outcome showed no significant difference in pain scores among groups. Secondary outcomes showed significantly lower pain scores at rest and during activity in the distal AC group than in the femoral triangle and proximal AC groups in the morning of the second postoperative day. Quadriceps strength and opioid consumption did not differ among groups.

Conclusions

Continuous femoral triangle, proximal AC, and distal AC blocks in the setting of periarticular local anesthetic infiltration provide comparable postoperative analgesia after total knee arthroplasty.

Trial registration number

NCT04206150.

Early Postoperative Pain Control and Inflammation for Total Knee Arthroplasty: A Retrospective Comparison of Continuous Adductor Canal Block versus Single-Shot Adductor Canal Block Combined with Patient-Controlled Intravenous Analgesia

Objective

The aim of this study was to compare pain control and inflammation among patients who received a continuous adductor canal block (CACB) versus single-shot adductor canal block (SACB) combined with patient-controlled intravenous analgesia (PCIA) for total knee arthroplasty (TKA) analgesia in the first two days after surgery.

Design

Matched cohort retrospective study. Setting. University hospital. Patients. One hundred fifty-six patient charts were included in this study: 78 patients with CACB in Group A and 78 patients with SACB combined with PCIA in Group B. Patients were matched according to age, body mass index, and American Society of Anesthesiologists class. Measurements. The primary outcome of the study was Visual Analogue Scale (VAS) pain scores before operation (Pre) and at postoperative 6 (POH6), 12 (POH12), 24 (POH24), 30 (POH30), 36 (POH36), and 48 hours (POH48). Secondary outcomes included patient-controlled bolus, time of first postoperative ambulation, range of knee flexion and extension, inflammation cytokines on Pre and POH48, percentage of remedial analgesics treatment, incidence of adverse events and complications, hospital stay and cost, and Numerical Rating Scale (NRS) satisfaction scores at discharge. Main Results. Mean VAS scores at rest and with motion were lower in Group B than in Group A on all postoperative hours. At POH30, compared with Group A (1.1 ± 0.6), mean VAS scores at rest in Group B (0.9 ± 0.4) were lower (P=0.048), and compared with Group A (2.6 ± 0.7), mean VAS scores with motion in Group B (2.2 ± 0.8) were lower (P=0.001). The number of patient-controlled bolus was 4.3 ± 1.6 (95% CI 3.9-4.6) in Group A and 3.1 ± 1.3 (95% CI 2.8-3.4) in Group B, respectively (P < 0.001). Patients in Group B displayed better functional recovery and inflammation results at POH48 than Group A with respect to range of knee flexion and extension (117.8 ± 10.9° vs. 125.2 ± 9.4°, P < 0.001) and inflammation cytokines, including erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and interleukin-6 (IL-6) ((43.8 ± 16.1) vs. (36.8 ± 13.2), P=0.003; (34.9 ± 9.4 mg/L) vs. (29.6 ± 10.6 mg/L), P=0.001; (21.3 ± 8.7 pg/ml) vs. (14.0 ± 7.0 pg/ml), P < 0.001)).

Conclusion

SACB combined with PCIA in the first two days of patients undergoing TKA has better analgesic and beneficial effects on functional recovery and inflammation.

Anatomical and Technical Considerations of the Hi-PAC (Hi-Volume Proximal Adductor Canal) Block: A Novel Motor-Sparing Regional Analgesia Technique for Below-Knee Surgeries

Below-knee surgeries are among the most commonly performed orthopedic or plastic and reconstructive procedures. They are associated with significant postoperative pain despite the use of systemic analgesics. The regional analgesia (RA) technique has been proven beneficial for better patient outcomes when used as an adjunct to multimodal analgesia in the early postoperative period. However, apprehension of an acute compartment syndrome (ACS) can limit the administration of appropriate RA techniques in such surgeries, leading to more opioid consumption to meet the increasing analgesic demands. Many modifications in the RA related to techniques and the local anesthetic type, concentration, and volume have been described to tackle such situations. The ideal RA technique should provide procedure-specific analgesia below the knee joint without affecting motor power and/or causing any delay in diagnosing or treating ACS.

The high-volume proximal adductor canal (Hi-PAC) block is a novel RA technique described as motor-sparing and procedure-specific for the below-knee surgeries. The Hi-PAC block, a single-injection technique, is administered in the proximal adductor canal targeting the saphenous nerve and depositing local anesthetics (LA) adjacent to the femoral artery below the vasoadductor membrane (VAM). By directly blocking the saphenous nerve and indirectly the sciatic nerve, it covers the entire innervation of the pain-generating components involved in the below-knee surgeries.

This article describes the anatomical and technical considerations of the Hi-PAC block and provides background knowledge of the relevant anatomy and sonoanatomy for a better understanding of its intricacies.

Comparing Analgesic Efficacy of a Novel Dual Subsartorial Block Using Two Different Volumes in Patients Undergoing Total Knee Arthroplasty: A Prospective, Double-Blind, Monocentric, Randomised Trial

Introduction: Total knee arthroplasty (TKA) is a life-changing joint surgery that improves health-related quality of life and functional status. Patients in need of this surgery mostly belong to the geriatric age group with limited functional reserves and multiple co-morbidities requiring utmost perioperative care with the most suitable analgesic modalities. Regional analgesia (RA) should provide effective analgesia while allowing early mobility, reduced opioid consumption, and early discharge. Dual subsartorial block (DSB) is a novel procedure-specific, motor-sparing, and opioid-sparing RA technique for TKA surgeries. Our study compared the analgesic efficacy of the two different combinations of volumes used in DSB.

Methods: This prospective randomized comparative study included patients between 25-75 years of age of American Society of Anesthesiology (ASA) I-II grades who underwent an elective cemented unilateral total knee replacement performed via medial approaches under neuraxial anesthesia. A total of 104 patients were divided into two equal groups based on the local anesthetic (LA) volumes (Group A 10/20 ml and Group B 20/10 ml) used in the DSB. Postoperative pain scores (using a visual analog scale) and quadriceps strengths (using neurological exam), and opioid consumption were measured at regular intervals till discharge.

Results: Most patients (71.2%) remained pain-free and comfortable until discharge, while 28.8% complained of pain within 12 hours of DSB. Mean quadriceps strength remained almost normal (4-5/5) until the discharge with no incidences of buckling or fall in either group. Over time, the postoperative trend between the groups showed a significant difference for dynamic pain (p = 0.002) and quadriceps strength (p = <0.001). There was an insignificant difference (p = 0.161) between the groups regarding opioid consumption, with the median oral morphine equivalent of zero in both groups. 

Discussion: The effective analgesic coverage of DSB is based on the involvement of all innervations of the procedure-specific pain generators of TKR surgeries. The specific focus on selective sensory innervations and the type/volume of the LA used makes DSB a motor-sparing RA alternative that facilitates early mobility and discharge. It can provide effective postoperative analgesia without compromising the motor strength of the quadriceps muscle when administered in either 10/20 or 20/10 volumes.

Effect of ultrasound-guided selective sensory nerve blockade of the knee on pain management compared with periarticular injection for patients undergoing total knee arthroplasty: A prospective randomized controlled trial

BACKGROUND

Ultrasound-guided selective sensory nerve blockade (SSNB) of the knee, including an adductor canal block (ACB), anterior femoral cutaneous nerve block, and infiltration between the popliteal artery and posterior capsule of the knee may provide effective motor-sparing knee analgesia for total knee arthroplasty (TKA). We hypothesized that the SSNB would manage pain better on ambulation 24 hours postoperatively compared to periarticular infiltration (PAI), when combined with postoperative continuous ACB.

METHODS

Seventy-two patients undergoing elective TKA under spinal anesthesia were randomly assigned to either SSNB (SSNB group) or intraoperative PAI (PAI group). All patients received postoperative multimodal analgesia, including continuous ACB. The primary outcome was pain on ambulation 24 hours postoperatively. Secondary outcomes included rest and dynamic numerical rating scale pain score, intravenous morphine requirement, functional performance measures, adverse events, satisfaction, and length of stay.

RESULTS

There was no difference in pain score during movement between the groups (mean difference -0.48 [-1.38 to 0.42], p = 0.3) and other immediate overall pain scores 24 hours postoperatively. Patients in the SSNB group had significantly lower intravenous morphine requirement than the PAI group for 48 hours postoperatively (0 [0, 0] vs. 0 [0, 2]; p = 0.008). There was no intergroup difference in the performance-based measures, satisfaction, and length of stay.

CONCLUSIONS

The SSNB did not provide superior postoperative analgesia, or improvement in immediate functional performance. However, it may result in lower opioid consumption postoperatively when compared with the intraoperative PAI.

Adding a low-concentration sciatic nerve block to total knee arthroplasty in patients susceptible to the adverse effects of non-steroidal anti-inflammatory drugs (NSAIDs): a randomized controlled trial

Background

This study compared the effects of adductor canal blocks with those of a low concentration of popliteal-sciatic nerve block (SNB) and dexamethasone as an adjunctive technique for total knee arthroplasties (TKA) in patients susceptible to the adverse effects of NSAIDs.

Methods

A prospective, double-blinded, randomized controlled trial was performed in 50 patients susceptible to the adverse effects of NSAIDs undergoing unilateral TKAs. All patients received spinal anesthesia, adductor canal blocks, and periarticular infiltration. The 25 patients in the intervention group received SNB (0.125% bupivacaine [20 ml] and dexamethasone [5 mg]).

Results

The SNB group significantly had lower median resting pain scores at 6, 12, and 18 h: the control group, 1 (0–4.5), 3 (0–5), and 3 (2–5); the intervention group, 0 (0–0), 0 (0–3), and 1 (0–3); p-values, 0.012, 0.021, and 0.010, respectively. Movement-evoked pain scores at 6, 12, and 18 h were also lower: control group, 3 (0–5.5), 5 (2.5–6.5), and 7 (4–9); intervention group, 0 (0–1.5), 2 (0–4), and 3 (2–5); p-values, 0.019, 0.005, and 0.001, respectively. There were no differences in motor function. Moreover, the mean morphine consumption 24 h was also reduced in the SNB group: control group, 3.80 ± 2.48 mg; intervention group, 1.96 ± 2 mg; p-value, 0.005.

Conclusion

For patients susceptible to the adverse effects of NSAIDs, a low concentration of SNB and dexamethasone is an effective adjunctive technique for early postoperative pain control (especially on movement) following TKAs, without an increase in motor weakness.

Trial registration

ClinicalTrials.gov, NCT03486548, Registered 3 April 2018.

Comparison of 2 Peripheral Nerve Blocks Techniques for Functional Recovery and Postoperative Pain Management After Total Knee Arthroplasty: A Prospective, Double-Blinded, Randomized Trial

BACKGROUND Methods of pain management that have less effect on motor function after total knee arthroplasty (TKA) are needed to ensure early mobilization. We investigated whether the distal femoral triangle and distal adductor canal blocks are superior to the femoral nerve block regarding motor blockade at early postoperative hours. MATERIAL AND METHODS Patients scheduled for TKA under spinal anesthesia were blindly assigned into 2 groups. One group received the distal femoral triangle and distal adductor canal blocks and the other group received the femoral nerve block. In both groups, at 3, 6, 24, and 48 h after surgery motor blockade was evaluated with the Bromage scale. Secondary outcomes such as pain control efficacy and patient satisfaction were evaluated at 6, 24, and 48 h postoperatively using either the VAS scale or a 10-point scale. RESULTS We analyzed the outcomes of 77 patients. Better motor function at 3 and 6 h after TKA was observed in the distal femoral triangle and the distal adductor canal blocks group (37.7% vs 23.4%, p=0.032 and 49.4% vs 32.5%, p=0.002, respectively). At 24 h after the surgery, patients from the femoral nerve block group consumed significantly more rescue opioid analgesics (p=0.016). We found no significant differences in pain intensity and patient satisfaction at any timepoints after the surgery. CONCLUSIONS The distal femoral triangle and distal adductor canal blocks resulted in significantly better motor function at the first 3 and 6 h after total knee arthroplasty. At 24 h after surgery, rescue opioid doses in the femoral nerve block group were significantly higher.

The analgesic efficacy of anterior femoral cutaneous nerve block in combination with femoral triangle block in total knee arthroplasty: a randomized control trial

Background

Ultrasound-guided femoral triangle block (FTB) can provide motor-sparing anterior knee analgesia. However, it may not completely anesthetize the anterior femoral cutaneous nerve (AFCN). We hypothesized that an AFCN block (AFCNB) in combination with a FTB would decrease pain during movement in the immediate 12-hour postoperative compared with a FTB alone.

Methods

Eighty patients scheduled to undergo total knee arthroplasty (TKA) were randomized to receive either FTB alone (FTB group) or AFCNB with FTB (AFCNB + FTB group) as a part of the multimodal analgesic regimen. The primary outcome was pain during movement 12 hours postoperatively. Secondary outcomes included numeric rating scale (NRS) pain scores, incidence of surgical incision site pain, intravenous morphine consumption, immediate functional performance, patient satisfaction, and length of hospital stay.

Results

The NRS pain scores on movement 12 hours postoperatively were significantly lower in patients of AFCNB + FTB group compared to those in patients of FTB group (mean difference, -2.02 [95% confidence interval: -3.14, -0.89], P < 0.001). Incidence of pain at the site of surgical incision in 24 hours postoperatively and morphine consumption in 48 hours postoperatively were significantly lower (P < 0.001) and quadriceps muscle strength at 0 degree immediately after the surgery was significantly greater in patients of AFCNB + FTB group (P = 0.04).

Conclusions

The addition of ultrasound-guided AFCNB to FTB provided more effective analgesia and decreased opioid requirement compared to FTB alone after TKA and may enhance immediate functional performance on the day of surgery.

Combination of femoral triangle block and infiltration between the popliteal artery and the capsule of the posterior knee (iPACK) versus local infiltration analgesia for analgesia after anterior cruciate ligament reconstruction: a randomized controlled triple-blinded trial

BACKGROUND AND OBJECTIVES

Femoral triangle block and local infiltration analgesia are two effective analgesic techniques after anterior cruciate ligament reconstruction. Recently, the iPACK block (infiltration between the popliteal artery and the capsule of the posterior knee) has been described to relieve posterior knee pain. This randomized controlled triple-blinded trial tested the hypothesis that the combination of femoral triangle block and iPACK provides superior analgesia to local infiltration analgesia after anterior cruciate ligament reconstruction.

METHODS

Sixty patients undergoing anterior cruciate ligament reconstruction received general anesthesia and were randomly allocated to two groups: femoral triangle block and iPACK under ultrasound guidance or local infiltration analgesia. For each group, a total of 160 mg of ropivacaine was injected. Postoperative pain treatment followed a predefined protocol with intravenous morphine patient-controlled analgesia, acetaminophen, and ibuprofen. The primary outcome was cumulative intravenous morphine consumption at 24 hours postoperatively. Secondary pain-related outcomes included pain scores (Numeric Rating Scale out of 10) measured at 2 and 24 hours postoperatively. Functional outcomes, such as range of motion and quadriceps strength, were also recorded at 24 postoperative hours, and at 4 and 8 postoperative months.

RESULTS

Cumulative intravenous morphine consumption at 24 hours postoperatively was significantly reduced in the femoral triangle block and iPACK group (femoral triangle block and iPACK: 9.7 mg (95% CI: 6.7 to 12.7); local infiltration analgesia: 17.0 mg (95% CI: 11.1 to 23.0), p=0.03). Other pain-related and functional-related outcomes were similar between groups.

CONCLUSIONS

The combination of femoral triangle block and iPACK reduces intravenous morphine consumption during the first 24 hours after anterior cruciate ligament reconstruction, when compared with local infiltration analgesia, without effect on other pain-related, early, or late functional-related outcomes.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov Registry (NCT03680716).

Continuous block at the proximal end of the adductor canal provides better analgesia compared to that at the middle of the canal after total knee arthroplasty: a randomized, double-blind, controlled trial

Background

The optimal position for continuous adductor canal block (ACB) for analgesia after total knee anthroplasty (TKA) remians controversial, mainly due to high variability in the localization of the the adductor canal (AC). Latest neuroanatomy studies show that the nerve to vastus medialis plays an important role in innervating the anteromedial aspect of the knee and dives outside of the exact AC at the proximal end of the AC. Therefore, we hypothesized that continuous ACB at the proximal end of the exact AC could provide a better analgesic effect after TKA compared with that at the middle of the AC (which appeared to only block the saphenous nerve).

Methods

Sixty-two adult patients who were scheduled for a unilateral TKA were randomized to receive continuous ACB at the proximal end or middle of the AC. All patients received patient-controlled intravenous analgesia with sufentanil postoperatively. The primary outcome measure was cumulative sufentanil consumption within 24 h after the surgery, which was analyzed using Mann-Whitney U tests. P-values < 0.05 (two-sided) were considered statistically significant. The secondary outcomes included postoperative sufentanil consumption at other time points, pain at rest and during passive knee flexion, quadriceps motor strength, and other recovery related paramaters.

Results

Sixty patients eventually completed the study (30/group). The 24-h sufentanil consumption was 0.22 μg/kg (interquartile range [IQR]: 0.15–0.40 μg/kg) and 0.39 μg/kg (IQR: 0.23–0.52 μg/kg) in the proximal end and middle groups (P = 0.026), respectively. There were no significant inter-group differences in sufentanil consumption at other time points, pain at rest and during passive knee flexion, quadriceps motor strength, and other recovery related paramaters.

Conclusions

Continuous ACB at the proximal end of the AC has a better opioid-sparing effect without a significant influence on quadriceps motor strength compared to that at the middle of the AC after TKA. These findings indicates that a true ACB may not produce the effective analgesia, instead, the proximal end AC might be a more suitable block to alleviate pain after TKA.

Trial registration

This study was registered at ClinicalTrials.gov (NCT03942133; registration date: May 06, 2019; enrollment date: May 11, 2019).

Total postoperative analgesia for total knee arthroplasty: Ultrasound guided single injection modified 4 in 1 block

Background and Aims:

Total pain free outcome following total knee arthroplasty has led to the evolution of regional blocks. In this series, the authors have revisited and modified Roy et al. 's technique of Ultrasound guided 4 in 1 block for knee and below knee surgeries, to provide a complete comprehensive yet simple single injection technique for postoperative analgesia for Total Knee Arthroplasty (TKA).

Material and Methods:

After Instituional ethics approval, we performed the modified 4 in 1 block on 10 consenting patients scheduled to undergo total knee arthroplasty. A linear USG-probe was used to identify medial femoral condyle, then vastus and sartorius intersection was identified. The probe was slid till the descending genicular artery branching from superficial femoral artery was visualized proximal to hiatus. At this point the needle with PNS attached, was guided into the Vastus medialis muscle till the stimulation of the nerve to Vastus medialis (0.4-0.5 mA). At this point 5–7 mL of 0.2% Ropivacaine was injected. The needle was guided in plane to perivascular region and after negative aspiration 0.2%ropivacaine 20–25 ml was injected, visualised to push the femoral artery.

Results:

All ten patients considered in this study had an optimum pain score of <5 and were comfortable along with no quadriceps weakness, except one patient had a pain score of more than 5 after 36 hr post-operatively and required rescue analgesia.

Conclusion:

The addition of USG and PNS guided Vastus medialis nerve block to USG 4-in-1 block in the technique gives good post-operative analgesia for TKA.

Analgesic efficacy of adding the IPACK block to a multimodal analgesia protocol for primary total knee arthroplasty

Background and objectives

Peripheral nerve blocks have been integrated into most multimodal analgesia protocols for total knee arthroplasty (TKA). The adductor canal block (ACB) has gained popularity because of its quadriceps muscle sparing. Similarly, local anesthetic injection between the popliteal artery and the posterior capsule of the knee, IPACK block, has been described to provide analgesia to the posterior capsule of the knee with motor-sparing qualities. This prospective randomized controlled trial aimed to assess the analgesic efficacy of adding the IPACK block to our current multimodal analgesic regimen, including the ACB, in patients undergoing primary TKA.

Methods

119 patients were randomized to receive either an IPACK or a sham block in addition to multimodal analgesia and an ACB. We were set to assess pain in the back of the knee 6 hours after surgery. Other end points included quality of recovery after surgery, pain scores, opioid requirements, and functional measures.

Results

Patients who received the IPACK block had less pain in the back of the knee 6 hours after surgery when compared with the sham block: 21.7% vs 45.8%, p<0.01. There was marginal improvement in other pain measures in the first 24 hours after surgery. However, opioid requirements, quality of recovery and functional measures were similar between the two groups.

Conclusion

The IPACK block reduced the incidence of posterior knee pain 6 hours postoperatively.

Comparison of the ultrasound-guided single-injection femoral triangle block versus adductor canal block for analgesia following total knee arthroplasty: a randomized, double-blind trial

PURPOSE

The aim of the study is to compare the femoral triangle (FT) and adductor canal (AC) blocks in terms of the analgesic efficacy and ambulatory outcomes in the context of multimodal analgesia following total knee arthroplasty (TKA).

METHODS

Patients presenting for TKA were assigned to a preoperative ultrasound-guided single-injection FT or AC block. Combined spinal and epidural anesthesia with bupivacaine was administered for TKA. Perioperatively a multimodal analgesic regimen was applied up to 48 h after surgery. The primary outcome was the average pain score during movement in the first 24 h postoperatively. The secondary outcomes included pain scores at rest and during movement at postoperative predetermined time points, cumulative opioid consumption in oral morphine equivalents, functional mobility measured by the timed "Up and Go" (TUG) test and muscle strength in the lower extremity.

RESULTS

Ninety-eight patients completed the study. Patients in the FT group had lower median pain scores during movement in the first 24 h postoperatively than those in the AC group (1.3 [1.0-3.3] vs. 3.0 [1.7-4.3]; median difference: - 1.0, adjusted 95% CI from - 1.7 to - 0.3, P = 0.010). There were significant differences in the pain scores at rest and during movement at 12 and 24 h postoperatively between the two groups (P = 0.008 and 0.005, respectively). Cumulative oral morphine equivalent consumption in the first and second 24 h postoperatively, Functional mobility reflected by the TUG test and muscle strength in the lower extremity showed no significantly statistically differences between the two groups.

CONCLUSIONS

The preoperative FT block provided improved analgesic outcomes without compromising functional mobility in the context of multimodal analgesia following TKA compared with the AC block.

TRIAL REGISTRATION

https://www.chictr.org.cn . Identifier: ChiCTR-INR-17012716.

AAAPT Diagnostic Criteria for Acute Knee Arthroplasty Pain

OBJECTIVE

The relationship between preexisting osteoarthritic pain and subsequent post-total knee arthroplasty (TKA) pain is not well defined. This knowledge gap makes diagnosis of post-TKA pain and development of management plans difficult and may impair future investigations on personalized care. Therefore, a set of diagnostic criteria for identification of acute post-TKA pain would inform standardized management and facilitate future research.

METHODS

The Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks (ACTTION) public-private partnership with the US Food and Drug Administration (FDA), the American Pain Society (APS), and the American Academy of Pain Medicine (AAPM) formed the ACTTION-APS-AAPM Pain Taxonomy (AAAPT) initiative to address this goal. A multidisciplinary work group of pain experts was invited to conceive diagnostic criteria and dimensions of acute post-TKA pain.

RESULTS

The working group used contemporary literature combined with expert opinion to generate a five-dimensional taxonomical structure based upon the AAAPT framework (i.e., core diagnostic criteria, common features, modulating factors, impact/functional consequences, and putative mechanisms) that characterizes acute post-TKA pain.

CONCLUSIONS

The diagnostic criteria created are proposed to define the nature of acute pain observed in patients following TKA.

Evaluation of the proximal adductor canal block injectate spread: a cadaveric study

BACKGROUND AND OBJECTIVES

Quadriceps sparing adductor canal block has emerged as a viable intervention to manage pain after total knee arthroplasty. Recent studies have defined ultrasound (US) landmarks to localize the proximal and distal adductor canal. US-guided proximal adductor canal injection has not been investigated using these sonographic landmarks. The objectives of this cadaveric study were to evaluate dye injectate spread and quantify the capture rates of nerves supplying articular branches to the knee joint capsule using a proximal adductor canal injection technique.

METHODS

A US-guided proximal adductor canal injection with 10 mL of dye was performed in seven lightly embalmed specimens. Following injection, specimens were dissected to document dye spread and frequency of nerve staining.

RESULTS

Following proximal adductor canal injection, dye spread consistently stained the deep surface of sartorius, vastoadductor membrane, aponeurosis of the vastus medialis obliquus, and adductor canal. The saphenous nerve, posteromedial branch of nerve to vastus medialis, superior medial genicular nerve and genicular branch of obturator nerve were captured in all specimens at the proximal adductor canal. There was minimal to no dye spread to the distal femoral triangle, anterior division of the obturator nerve and anterior branches of nerve to vastus medialis.

CONCLUSIONS

This anatomical study provides some insights into the mechanism of analgesia to the knee following a proximal adductor canal injection and its motor sparing properties. Further clinical investigation is required to confirm cadaveric findings.

Anesthesia of the anterior femoral cutaneous nerves for total knee arthroplasty incision: randomized volunteer trial

BACKGROUND AND OBJECTIVES

For pain relief after total knee arthroplasty (TKA), an injection at the midthigh level may produce analgesia inferior to that of a femoral nerve block as the anterior femoral cutaneous nerves (intermediate femoral cutaneous nerve (IFCN) and medial femoral cutaneous nerve (MFCN)) are not anesthetized. The IFCN can be selectively anesthetized in the subcutaneous tissue above the sartorius muscle and the MFCN by an injection in the proximal part of the femoral triangle (FT). The primary aim was to investigate the area of cutaneous anesthesia in relation to the surgical incision for TKA and anteromedial knee area after intermediate femoral cutaneous nerve blockade (IFCNB) in combination with an injection in the proximal or distal part of the FT (proximal vs distal femoral triangle block (FTB)).

METHODS

The study was carried out as two separate investigations: first, dissection of nine cadaver sides to verify a technique for IFCNB; second, a volunteer study with 40 healthy volunteers. The surgical midline incision for TKA was drawn bilaterally. All volunteers received an active distal FTB combined with a placebo proximal FTB on one side and vice versa on the other side. All volunteers were randomized to an active IFCNB on one side and placebo IFCNB on the contralateral side.

RESULTS

Identification of IFCN was successful in all cadaver sides. Fifteen out of 20 volunteers had complete anesthesia of the incision line after IFCNB combined with proximal FTB, which was significantly higher compared with proximal FTB alone and with distal FTB+IFCNB. A gap at the anteromedial knee area was present in 2/20 volunteers with proximal FTB compared with 17/20 with distal FTB when all volunteers had active IFCNB.

CONCLUSION

Ultrasound-guided blockade of the IFCN and MFCN anesthetize the surgical midline incision and the anteromedial area of the knee relevant for TKA. In contrast, an injection at the midthigh level produces insufficient cutaneous anesthesia not covering the areas of interest.

TRIAL REGISTRATION NUMBER

EudraCT: 2018-004986-15.

Opioid- and Motor-sparing with Proximal, Mid-, and Distal Locations for Adductor Canal Block in Anterior Cruciate Ligament Reconstruction

Editor’s Perspective

What We Already Know about This Topic

What This Article Tells Us That Is New

Background

The ideal location for single-injection adductor canal block that maximizes analgesia while minimizing quadriceps weakness after painful knee surgery is unclear. This triple-blind trial compares ultrasound-guided adductor canal block injection locations with the femoral artery positioned medial (proximal adductor canal), inferior (mid-adductor canal), and lateral (distal adductor canal) to the sartorius muscle to determine the location that optimizes postoperative analgesia and motor function. The hypothesis was that distal adductor block has (1) a superior opioid-sparing effect and (2) preserved quadriceps strength, compared with proximal and mid-locations for anterior cruciate ligament reconstruction.

Methods

For the study, 108 patients were randomized to proximal, mid-, or distal adductor canal injection locations for adductor canal block. Cumulative 24-h oral morphine equivalent consumption and percentage quadriceps strength decrease (maximum voluntary isometric contraction) at 30 min postinjection were coprimary outcomes. The time to first analgesic request, pain scores, postoperative nausea/vomiting at least once within the first 24 h, and block-related complications at 2 weeks were also evaluated.

Results

All patients completed the study. Contrary to the hypothesis, proximal adductor canal block decreased 24-h morphine consumption to a mean ± SD of 34.3 ± 19.1 mg, (P &lt; 0.0001) compared to 64.0 ± 33.6 and 65.7 ± 22.9 mg for the mid- and distal locations, respectively, with differences [95% CI] of 29.7 mg [17.2, 42.2] and 31.4 mg [21.5, 41.3], respectively, mostly in the postanesthesia care unit. Quadriceps strength was similar, with 16.7%:13.4%:15.3% decreases for proximal:mid:distal adductor canal blocks. The nausea/vomiting risk was also lower with proximal adductor canal block (10 of 34, 29.4%) compared to distal location (23 of 36, 63.9%; P = 0.005). The time to first analgesic request was longer, and postoperative pain was improved up to 6 h for proximal adductor canal block, compared to mid- and distal locations.

Conclusions

A proximal adductor canal injection location decreases opioid consumption and opioid-related side effects without compromising quadriceps strength compared to mid- and distal locations for adductor canal block in patients undergoing anterior cruciate ligament reconstruction.

Accuracy of fluoroscopic-guided genicular nerve blockade: a need for revisiting anatomical landmarks

BACKGROUND AND OBJECTIVES

Genicular nerve blockade (GNB) and radiofrequency ablation (RFA) have recently emerged as treatment options for patients with chronic knee pain. However, an increasing number of anatomical studies and systematic reviews concluded that the anatomical basis for needle placement was unclear, incomplete and somewhat inaccurate. This study was designed to assess the accuracy of updated anatomical landmarks for fluoroscopy-guided blockade of the consistent genicular nerves in a cadaveric model.

METHODS

Based on a comprehensive review of recent anatomical studies and prior dissection of 21 fresh cadaver knees, we defined bony landmarks with high likelihood of successful ablation of the five consistent genicular nerves (GN). We tested the accuracy of GNBs using the above-stated anatomical landmarks in 10 intact fresh cadaveric knees. Needle placement was guided by fluoroscopy and 0.5 mL of 0.1% methylene blue was injected at the site of each nerve. The knees were subsequently dissected to assess the accuracy of the injections. If the nerve was dyed with blue ink, the placement was considered accurate.

RESULTS

The accuracy of our injections was 100% for the superior medial genicular nerve, inferior medial GN, infrapatellar branch of saphenous nerve and recurrent fibular nerve. The superior lateral GN was dyed in 90% of specimens.

CONCLUSION

This study provides physicians with precise anatomical landmarks for the five consistent GN for fluoroscopic-guided GNB. Our revised technique, which targets more nerves with increased accuracy, could potentially lead to improved therapeutic benefits on chronic knee pain.