Randomized Prospective Comparative Study of Adductor Canal Block vs Periarticular Infiltration on Early Functional Outcome After Unilateral Total Knee Arthroplasty

Addition of Surgeon-Administered Adductor Canal Infiltration to the Periarticular Infiltration in Total Knee Arthroplasty: Effect on Pain and Early Outcomes

BACKGROUND

Our aim was to study the additive effect of surgeon-administered adductor canal infiltration (SACI) over routine periarticular infiltration (PAI) on pain control [morphine consumption and pain score by the visual analog scale (VAS)] and early function [flexion and Timed Up and Go (TUG) test] post-total knee arthroplasty (TKA).

METHODS

We prospectively randomized 60 patients into 2 groups. Group I patients received the standard PAI, whereas in Group II, the patients received a SACI in addition to the PAI. The total volume of the injected drug and the postoperative pain management protocol were the same for all. The number of doses of patient-controlled analgesia (PCA) used for breakthrough pain was recorded as PCA consumption. For early function, flexion and the TUG test were used. The VAS score and PCA consumption were compared between the 2 groups by using analyses of variance with post hoc tests as indicated. The TUG test and flexion were compared using Student t tests. The level of significance was set at 0.05.

RESULTS

The PCA consumption in the first 6 hours was significantly higher in Group I (P = .04). The VAS at 6 hours was significantly lower in Group II (P = .042). The TUG test was comparable between the 2 groups preoperatively (P = .72) at 24 hours (P = .60) and 48 hours (P = .60) post-TKA. The flexion was comparable between the 2 groups preoperatively (P = .85) at 24 hours (P = .48) and 48 hours (P = .79) post-TKA.

CONCLUSIONS

Adding a SACI to PAI provides improved pain relief and reduces opioid consumption without affecting early function post-TKA. A SACI avoids the need for an anesthesiologist or specialized equipment with no added operating time and minimal added cost. We recommend routine use of SACI for all patients undergoing TKA.

Posteromedial Periarticular Injection in Total Knee Arthroplasty: A Cadaveric Study

Achieving optimal pain control in total knee arthroplasty has improved with the use of regional anesthesia and periarticular injections (PAIs). When performing a PAI, the relative location of the anesthetic spread is not well defined in comparison with an adductor canal block (ACB). In this study, our aim was to evaluate the location of posteromedial PAI spread compared with a surgeon administered ACB. One PAI and one surgeon-administered ACB were performed in the contralateral limbs of four human cadavers. The injectate was composed of methylene blue dye to visually inspect the dye spread from the tip of the needle. Dissections were performed on each cadaver to quantify the dye spread from the tip of the needle and compare the location of the dye spread. Dye spread location was characterized as either entering the adductor canal or including the posterior capsule. The mean distance of dye spread from the needle tip to the proximal most aspect of the dyed tissue was 10.125 cm in the ACB group compared with 6.5 cm in the posteromedial PAI group. In the ACB group, 4 of 4 injections were present in the adductor canal block group compared with 3 of 4 in the posteromedial PAI group. The posteromedial PAI group also had 3 of 4 injections involve the area around the posterior capsule compared with 0 of 4 in the ACB group. Posteromedial PAI appears to provide local delivery to both the adductor canal and the posterior capsule. Intraoperative, surgeon-administered ACB reliably delivers injectate to the adductor canal only but may allow for more proximal dye spread. Posteromedial PAI may provide a benefit in delivering injectate to the posterior capsule in addition to the ACB. Additional clinical studies are necessary to determine the clinical effects of this finding.

Comparison of ultrasound-guided genicular nerve block and knee periarticular infiltration for postoperative pain and functional outcomes in knee arthroplasty - A randomised trial

Background and Aims

Optimal analgesia after total knee arthroplasty (TKA) enhances patients' and surgical outcomes. The study investigated the ultrasound-guided genicular nerve block versus the periarticular infiltration in TKA.

Methods

Eighty-eight patients aged above 50 years scheduled for unilateral TKA were randomised as: Group 1 received intraoperative periarticular infiltration (0.5 mL adrenaline [4.5 µg/mL], 20 mL bupivacaine 0.5% with 89.5 mL saline) and Group 2 received immediate postoperative genicular nerve block (15 mL bupivacaine 0.25% with 2.5 g/mL adrenaline). The postoperative morphine consumption was during the first two postoperative days the primary outcome. The secondary outcomes were time to rescue analgesia, pain scores and functional outcomes. The comparison between groups was performed using the Chi-square test, the Student's t-test and the Mann-Whitney U test, as appropriate.

Results

The postoperative morphine consumption during the first two postoperative days and pain scores at rest at 12 h postoperatively were less in Group 1 than in Group 2 (P < 0.001). Pain scores during movement on the first postoperative day were lower in the periarticular group than the genicular group at 6, 12 and 24 h (P < 0.001). At 18 h, pain scores were higher in the periarticular group than in the genicular group at rest and movement (P < 0.001). Quadriceps motor strength scores were comparable between groups (P > 0.05). The knee range of motion and time up and go test during both days showed a statistically significant difference in the periarticular group compared to the genicular group (P < 0.05).

Conclusion

Periarticular infiltration and genicular nerve block yield effective postoperative analgesia and functional outcomes after TKA without motor affection.

Local Periarticular Infiltration with Dexmedetomidine Results in Superior Patient Well-Being after Total Knee Arthroplasty Compared with Peripheral Nerve Blocks: A Randomized Controlled Clinical Trial with a Follow-Up of Two Years

BACKGROUND

This study aimed to compare local periarticular infiltration (LIA) with ultra-sound guided regional anesthesia (USRA) with ropivacaine and dexmedetomidine as an additive agent in primary total knee arthroplasty (TKA).

METHODS

Fifty patients were randomized into two groups in a 1:1 ratio. Patients in the LIA group received local periarticular infiltration into the knee joint. The USRA group received two single-shot USRA blocks. Functional outcomes and satisfaction (range of movement, Knee Society Knee Score, Western Ontario and McMaster Universities Osteoarthritis Index, Oxford Knee Score, and Forgotten Joint Score), including well-being, were analyzed preoperatively and at five days, six weeks, and one and two years postoperatively.

RESULTS

Functional outcomes did not significantly differ between the two groups at six weeks and one and two years after the implementation of TKA. A moderate correlation was observed in the LIA group regarding well-being and pain on day five. Six weeks postoperatively, the LIA group showed significantly superior well-being but worse pain scores. No differences between the groups in well-being and functional outcomes could be observed one and two years postoperatively.

CONCLUSION

Patients treated with LIA had superior postoperative well-being in the early postoperative phase of up to six weeks. Furthermore, LIA patients had similar functionality compared to patients treated with USRA but experienced significantly more pain six weeks postoperatively. LIA leads to improved short-term well-being, which is potentially beneficial for faster knee recovery. We believe that LIA benefits fast-track knee recovery with respect to improved short-term well-being, higher practicability, and faster application.

Ropivacaine-Epinephrine-Clonidine-Ketorolac Cocktail as a Local Anesthetic for Lumbar Decompression Surgery: A Single Institutional Experience

OBJECTIVE

The goal of this study is to discuss our initial experience with a multimodal opioid-sparing cocktail containing ropivacaine, epinephrine, clonidine, and ketorolac (RECK) in the postoperative management of lumbar decompression surgeries.

METHODS

Patients were either administered no local anesthetic at the incision site or were administered a weight-based amount of RECK into the paraspinal musculature and subdermal space surrounding the operative site once the fascia was closed. We performed a retrospective chart review of all patients 18 years of age or older undergoing lumbar laminectomy and lumbar diskectomy surgeries between December 2019 and April 2021. Outcomes including total opioid use, measured as morphine milligram equivalent, length of stay, and postoperative visual analog scores for pain, were collected. Relationships between variables were analyzed with Student's t-test, chi-square tests, and Fisher exact tests.

RESULTS

A total of 121 patients undergoing 52 lumbar laminectomy and 69 lumbar diskectomy surgeries were identified. For lumbar laminectomy, patients who were administered RECK had decreased opioid use in the postoperative period (11.47 ± 12.32 vs. 78.51 ± 106.10 morphine milligram equivalents, P = 0.019). For patients undergoing lumbar diskectomies, RECK administration led to a shorter length of stay (0.17 ± 0.51 vs. 0.79 ± 1.45 days, P = 0.019) and a lower 2-hour postoperative pain score (3.69 ± 2.56 vs. 5.41 ± 2.28, P = 0.006).

CONCLUSIONS

The RECK cocktail has potential to be an effective therapeutic option for the postoperative management of lumbar decompression surgeries.

No Benefit of Adductor Canal Block Compared with Anterior Local Infiltration Analgesia in Primary Total Knee Arthroplasty: A Single-Blinded Randomized Controlled Clinical Trial

BACKGROUND

An adductor canal block (ACB) performed by an anesthesiologist is an established component of analgesia after total knee arthroplasty. Alternatively, surgeons may perform periarticular local infiltration analgesia (LIA) intraoperatively. We hypothesized that ACB would be superior to anterior LIA in terms of morphine consumption in the first 48 hours after primary total knee arthroplasty under spinal anesthesia.

METHODS

This prospective controlled and blinded trial included 98 patients; 48 received an ACB plus sham (saline solution) anterior LIA, and 50 received a sham (saline solution) ACB plus anterior LIA. Both groups received posterior LIA with local anesthetic. The primary outcome was cumulative morphine consumption at 48 hours after surgery. Secondary outcomes were pain while resting, standing, and walking, rehabilitation scores, opioid-related side effects, and patient satisfaction.

RESULTS

No difference in the primary outcome was found, and the 48-hour morphine consumption was low in both arms (28.8 ± 17.6 mg with ACB, 26.8 ± 19.2 mg with anterior LIA; p = 0.443). Pain scores were significantly better in the anterior LIA arm, but the differences were not clinically relevant. There were no differences in any other secondary outcome measures.

CONCLUSIONS

LIA may be used as the primary option for multimodal postoperative pain management in patients undergoing primary total knee arthroplasty with spinal anesthesia.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

The application of low-dose dexamethasone in total knee arthroplasty: finding out the best route and dosage schedule

BACKGROUND

The use of dexamethasone as additive to multimodal analgesic regimen in total knee arthroplasty has been well established, but the most suitable route, effectiveness, safety and dose schedule of low-dose dexamethasone is not known.

METHODS

We conducted a prospective, randomized, double-blinded trial to investigate and compare the analgesic and antiemetic effects and safety of low-dose (8 mg) dexamethasone introduced as periarticular injection or intravenous (as a single dose or in two divided doses of 4 mg separated by 24 h) in unilateral total knee arthroplasty patients.

RESULTS

The single dose intravenous administration as well as the periarticular administration of dexamethasone had similar mean visual analogue scores which were significantly lower than divided dose group at 24 and 48 h postoperatively. The rate of postoperative nausea and vomiting was lowest among single intravenous dose group and highest among interval dose group at 24 h, while no difference was noted at 48 h. No significant differences were noted in terms of knee flexion angle at 48 h and modified Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score at 6 weeks.

CONCLUSION

Single low-dose intravenous dexamethasone is the most appropriate dose which can safely be given to TKA patients and is only moderately associated with rise in blood sugar not causing any significant complication. Alternatively, periarticular infiltration of low-dose dexamethasone can produce equivalent analgesic effect as SDIV in first 24 h without causing significant blood sugar rise and wound complications, but its antiemetic effect remains subtle. Therefore, it is recommended to further study the combination of intraoperative periarticular and postoperative intravenous dexamethasone for their possible additive effect.

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.

The Efficacy and Safety of Regional Nerve Blocks in Total Knee Arthroplasty: Systematic Review and Direct Meta-Analysis

BACKGROUND

Regional nerve blocks are widely used in primary total knee arthroplasty (TKA) to reduce postoperative pain and opioid consumption. The purpose of our study was to evaluate the efficacy and safety of regional nerve blocks after TKA in support of the combined clinical practice guidelines of the American Association of Hip and Knee Surgeons, American Academy of Orthopaedic Surgeons, Hip Society, Knee Society, and American Society of Regional Anesthesia and Pain Management.

METHODS

We searched MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials for studies published before March 24, 2020 on femoral nerve block, adductor canal block, and infiltration between Popliteal Artery and Capsule of Knee in primary TKA. All included studies underwent qualitative and quantitative homogeneity testing followed by a systematic review and direct comparison meta-analysis to assess the efficacy and safety of the regional nerve blocks compared to a control, local peri-articular anesthetic infiltration (PAI), or between regional nerve blocks.

RESULTS

Critical appraisal of 1,673 publications yielded 56 publications representing the best available evidence for analysis. Femoral nerve and adductor canal blocks are effective at reducing postoperative pain and opioid consumption, but femoral nerve blocks are associated with quadriceps weakness. Use of a continuous compared to single shot adductor canal block can improve postoperative analgesia. No difference was noted between an adductor canal block or PAI regarding postoperative pain and opioid consumption, but the combination of both may be more effective.

CONCLUSION

Single shot adductor canal block or PAI should be used to reduce postoperative pain and opioid consumption following TKA. Use of a continuous adductor canal block or a combination of single shot adductor canal block and PAI may improve postoperative analgesia in patients with concern of poor postoperative pain control.

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.

Comparison of Efficacy of Adductor Canal Block, Local Infiltration Analgesia and Both Combined in Postoperative Pain Management After Total Knee Arthroplasty: A Randomized Controlled Trial

PURPOSE

The aim of our study is to compare the efficacy of adductor canal block (ACB), periarticular local infiltration (PLI) and both combined (ACB + PLI) in multimodal pain management after TKA.

METHODS

This is a prospective, randomized controlled double-blinded study undergoing primary unilateral TKA. They were randomized into three groups with fifty patients in each group: ACB alone (30 ml of 0.2% ropivacaine), PLI alone (30 ml 0.5% ropivacaine in 20 ml of normal saline), and both combined (ACB + PLI). The primary outcome studied was pain using visual analog score (VAS) in postoperative days (POD) 1 and 2. The secondary outcomes estimated were the ambulation capacity, the knee range of motion, need for rescue analgesia and length of hospital stay.

RESULTS

The mean VAS score was significantly lower at rest and after mobilization in the combined group (3.51 at POD 1, 2.04 at POD 2), compared with either alone group (ACB = 4.70, 2.86 versus PLI = 4.39, 3.41 at POD 1 and 2 respectively after mobilization, p < 0.001). The ambulation capacity (combined = 103.3 steps versus ACB = 98.1 and PLI = 95.2 steps, p = 0.04) and the knee range of motion (arc of motion 106.7 degrees versus ACB = 104.9 and PLI = 102.2 degrees, p = 0.004) were significantly higher in the combined group compared to the other groups. There was no significant difference in the length of stay between the groups (p = 0.12).

CONCLUSION

Adductor canal block combined with periarticular local infiltration provides better pain relief, good range of motion, quicker rehabilitation, and reduced opioid consumption.

Peripheral nerve block anesthesia/analgesia for patients undergoing primary hip and knee arthroplasty: recommendations from the International Consensus on Anesthesia-Related Outcomes after Surgery (ICAROS) group based on a systematic review and meta-analysis of current literature

BACKGROUND

Evidence-based international expert consensus regarding the impact of peripheral nerve block (PNB) use in total hip/knee arthroplasty surgery.

METHODS

A systematic review and meta-analysis: randomized controlled and observational studies investigating the impact of PNB utilization on major complications, including mortality, cardiac, pulmonary, gastrointestinal, renal, thromboembolic, neurologic, infectious, and bleeding complications.Medline, PubMed, Embase, and Cochrane Library including Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, NHS Economic Evaluation Database, were queried from 1946 to August 4, 2020.The Grading of Recommendations Assessment, Development, and Evaluation approach was used to assess evidence quality and for the development of recommendations.

RESULTS

Analysis of 122 studies revealed that PNB use (compared with no use) was associated with lower ORs for (OR with 95% CIs) for numerous complications (total hip and knee arthroplasties (THA/TKA), respectively): cognitive dysfunction (OR 0.30, 95% CI 0.17 to 0.53/OR 0.52, 95% CI 0.34 to 0.80), respiratory failure (OR 0.36, 95% CI 0.17 to 0.74/OR 0.37, 95% CI 0.18 to 0.75), cardiac complications (OR 0.84, 95% CI 0.76 to 0.93/OR 0.83, 95% CI 0.79 to 0.86), surgical site infections (OR 0.55 95% CI 0.47 to 0.64/OR 0.86 95% CI 0.80 to 0.91), thromboembolism (OR 0.74, 95% CI 0.58 to 0.96/OR 0.90, 95% CI 0.84 to 0.96) and blood transfusion (OR 0.84, 95% CI 0.83 to 0.86/OR 0.91, 95% CI 0.90 to 0.92).

CONCLUSIONS

Based on the current body of evidence, the consensus group recommends PNB use in THA/TKA for improved outcomes.

RECOMMENDATION

PNB use is recommended for patients undergoing THA and TKA except when contraindications preclude their use. Furthermore, the alignment of provider skills and practice location resources needs to be ensured. Evidence level: moderate; recommendation: strong.

A comparison of analgesic techniques for total knee arthroplasty: A network meta-analysis

STUDY OBJECTIVE

There is no established analgesic method for postoperative total knee arthroplasty. We comprehensively compared the analgesic methods for postoperative total knee arthroplasty.

DESIGN

A network meta-analysis of randomised controlled trials was used to compare 18 interventions, which were ranked by six outcome indices, to select the best modality.

SETTING

Postoperative recovery room and inpatient ward.

PATIENTS

98 randomised controlled trials involving 7452 patients (ASA I-III) were included in the final analysis.

INTERVENTIONS

Studies that included the use of at least one of the following 12 nerve block(fascia iliaca compartment block (FIB), FNB, cFNB, single femoral nerve block (sFNB), adductor canal block (ACB), sciatic nerve block (SNB), obturator nerve block (ONB), continuous posterior lumbar plexus block (PSOAS), FNB + SNB, ACB + LIA, FNB + LIA, PCA + FNB).

MEASUREMENTS

Pain intensity was compared using Visual Analogue Scale (VAS). Also, postoperative complications, function score, hospital length of stay, morphine consumption and patient satisfaction were measured.

MAIN RESULTS

For visual analogue scale scores, continuous femoral nerve block (FNB) and FNB + sciatic nerve block (SNB) were the the most effective interventions. For reducing postoperative complications, fascia iliaca compartment block, FNB, SNB, and obturator nerve block showed the best results. For reducing postoperative morphine consumption, adductor canal block (ACB) + local infiltration analgesia (LIA) and FNB + SNB were preferred. For function scores (range of motion, Timed-Up-and-Go test), ACB and LIA were optimal choices. For reducing hospital length of stay and patient satisfaction, ACB + LIA and FNB + LIA were best, respectively.

CONCLUSIONS

Peripheral nerve block, especially FNB and ACB, is a better option than other analgesic methods, and its combination with other methods can be beneficial. Peripheral nerve block is a safe and effective postoperative analgesia method. However, our findings can only provide objective evidence. Clinicians should choose the treatment course based on the individual patient's condition and clinical situation.

Which is the best analgesia treatment for total knee arthroplasty: Adductor canal block, periarticular infiltration, or liposomal bupivacaine? A network meta-analysis

STUDY OBJECTIVE

To review all randomized controlled trials (RCTs) comparing the analgesic efficacy of adductor canal block (ACB), periarticular infiltration (PAI), and any other mode of these treatments in analgesia, such as PAI with liposomal bupivacaine (LB), continuous adductor canal block (cACB) or ACB + PAI, after total knee arthroplasty (TKA).

DESIGN

Systematic review and network meta-analysis of RCTs.

PATIENTS

We searched PubMed, Embase, and the Cochrane database to detect all relevant RCTs on investigating the analgesic effects of ACB, PAI and LB for TKA published until April 2020.

INTERVENTIONS

Use of different analgesic methods of ACB, PAI, cACB, ACB + PAI and LB.

MEASUREMENTS

The primary endpoint was visual analog scale (VAS) score at rest and movement. The secondary endpoints were opioids consumption, length of hospitalization and knee range of motion (ROM). We used Cochrane risk of bias to assess the quality of evidence for outcomes.

RESULTS

Forty-two studies involving 3785 patients with 5 different methods containing ACB, PAI, ACB + PAI, continuous ACB (cACB), LB, were evaluated. According to surface under the cumulative ranking curve value, 24 h resting VAS score was the lowest the ACB + PAI (88.4%), followed by cACB (73.4%); Resting VAS score at 48 h and movement VAS score at 24 h and 48 h was the lowest in the cACB (99.9%, 92% and 100%). Total opioids consumption was the least in LB (81.4%) before cACB (60.8%). ROM was the largest in the ACB + PAI (84.1%) before cACB (78.8%).

CONCLUSION

Although all analgesic methods available were not evaluated, and further studies are needed to establish our results, the 24 h resting VAS score was lowest in ACB + PAI and 48 h resting and movement VAS score was lowest in cACB.

CLINICAL TRIAL REGISTRATION

PROSPERO (CRD 42020168102).

Motor-sparing nerve blocks for total knee replacement: A scoping review

STUDY OBJECTIVE

This scoping review investigates the optimal combination of motor-sparing analgesic interventions for patients undergoing total knee replacement (TKR).

DESIGN

Scoping review.

INTERVENTION

MEDLINE, EMBASE and CINAHL databases were searched (inception-last week of May 2020). Only trials including motor-sparing interventions were included. Randomized controlled trials lacking prospective registration and blinded assessment were excluded.

MAIN RESULTS

The cumulative evidence suggests that femoral triangle blocks outperform placebo and periarticular infiltration. When combined with the latter, femoral triangle blocks are associated with improved pain control, higher patient satisfaction and decreased opioid consumption. Continuous femoral triangle blocks provide superior postoperative analgesia compared with their single-injection counterparts. However, these benefits seem less pronounced when perineural adjuvants are used. Combined femoral triangle-obturator blocks result in improved analgesia and swifter discharge compared with femoral triangle blocks alone.

CONCLUSIONS

The optimal analgesic strategy for TKR may include a combination of different analgesic modalities (periarticular infiltration, femoral triangle blocks, obturator nerve block). Future trials are required to investigate the incremental benefits provided by local anesthetic infiltration between the popliteal artery and the capsule of the knee (IPACK), popliteal plexus block and genicular nerve block.