Comparison of adductor canal block with local infiltration analgesia in primary total knee arthroplasty: A meta-analysis of randomized controlled trials

Does postoperative low-dose duloxetine provide analgesic effect and lower morphine consumption after primary total knee arthroplasty? A prospective, double-blind, randomized controlled trial

INTRODUCTION

Duloxetine as an adjunct analgesic has shown effective results in trials of patients undergoing total knee arthroplasty (TKA). However, the regimen has not been standardized. We, therefore, evaluated the analgesic efficacy of low-dose duloxetine after TKA.

MATERIALS AND METHODS

We conducted a double-blind, randomized controlled trial of patients undergoing unilateral primary TKA, comparing 30 mg/d of duloxetine for 6 weeks as an additive medication for pain control to modern multimodal analgesia after TKA. The primary outcome measure was a visual analogue scale (VAS) for pain at rest, during walking, and at night at 24 h, 72 h, 2 weeks, 6 weeks, and 12 weeks after the operation. Secondary outcomes were morphine consumption, adverse events, and functional outcomes: Oxford Knee Score, Knee injury and Osteoarthritis Outcome Score (KOOS).

RESULTS

Mean VAS for pain at rest, during walking, and at night at 24 h, 72 h, 2 weeks, 6 weeks, and 12 weeks showed no significant differences between the two groups, except a significantly lower mean VAS at night at 2 weeks in the duloxetine group. Mean total morphine consumption (0-72 h) was 33% less in the duloxetine group (6.8 ± 5.7 vs. 10.2 ± 7.3 mg, p = 0.04). There were no significant differences in adverse events and functional outcomes except better KOOS symptoms at 6 and 12 weeks in the duloxetine group.

CONCLUSION

Low-dose duloxetine could reduce postoperative morphine consumption and improve KOOS symptoms at 6 and 12 weeks with good tolerability. However, it did not significantly reduce pain at rest or during walking. Low-dose duloxetine can be considered an addition to contemporary multimodal pain management after TKA.

LEVEL OF EVIDENCE V

Therapeutic Level I.

Efficacy of Adding Acetaminophen to Preemptive Multimodal Analgesia in Total Knee Arthroplasty: A Double-blinded Randomized Study

OBJECTIVE

Preemptive multimodal analgesia is a frequently utilized method for controlling pain after total knee arthroplasty (TKA). So far, no studies have specifically examined the efficacy of adding acetaminophen to preemptive multimodal analgesia in TKA. The current work aimed to assess the efficacy of adding acetaminophen to preemptive multimodal analgesia for clinical pain management after TKA.

METHODS

This was a double-blinded randomized study including 80 cases randomized to the acetaminophen and control groups, respectively. The acetaminophen group was administered celecoxib at 400 mg, pregabalin at 150 mg, and acetaminophen at 300 mg 2 h before TKA. Control patients were administered celecoxib, pregabalin, and placebo. The primary outcome was postsurgical use of morphine hydrochloride for rescue analgesia. Secondary outcomes included the time to the initial rescue analgesia, postsurgical pain as determined by a visual analogue scale (VAS), functional recovery as reflected by the range of knee motion and ambulation distance, hospitalization duration, and complication rates. Continuous data with normal and skewed distributions were compared by the Student's t test and the Mann-Whitney U test, respectively. Categorical variables were compared by the Pearson's chi-squared test.

RESULTS

The control and acetaminophen groups were comparable in postoperative 0-24 h morphine consumption (11.3 ± 6.5 mg vs 12.3 ± 7.7 mg, P = 0.445) and total morphine consumption (17.3 ± 10.1 mg vs 19.3 ± 9.4 mg, P = 0.242). Additionally, time to the initial rescue analgesia, postoperative VAS score at any time point, postoperative functional recovery of the knee, and hospitalization duration were similar in both groups. Both groups also had similar occurrence rates of postoperative complications.

CONCLUSIONS

In this study, adding acetaminophen to preoperative preemptive multimodal analgesia did not decrease postoperative morphine use or ameliorate pain relief. The efficacy of adding acetaminophen to preemptive multimodal analgesia in TKA need to be further explored in future studies.

Does an Adductor Canal Block Influence Patient-Reported Outcomes at One Year Following Total Knee Arthroplasty?

Introduction Total knee arthroplasty (TKA) for osteoarthritis is performed to improve knee function and quality of life. Adductor canal block (ACB) (with posterior capsule local anaesthetic) and periarticular local anaesthetic infiltration (LA) alone are common methods used for post-operative pain control following TKA. The primary aim of this study was to investigate the influence of ACB compared to LA alone on knee function at one year in patients undergoing primary TKA. The secondary aims were to investigate the influence on health-related quality of life (HRQoL), patient satisfaction at one year, and length of stay (LOS) in hospital following TKA. Methods During a three-year period, 1396 patients who underwent TKA at the study centre completed pre-operative and one-year post-operative questionnaires. Data collected included patient demographics, co-morbidities, LOS, Oxford Knee Score (OKS), EuroQol 5-Dimension (EQ-5D) and satisfaction scores. Patients who had a spinal anaesthetic (n=1096) with either ACB (with posterior capsule local anaesthetic) (n=224) and LA infiltration alone (n=872) were compared. Results There was a significant improvement in pre-operative to one-year post-operative knee function as measured by OKS overall (15.1, p<0.001), however there was no significant difference between ACB and LA groups (p=0.37). There was no significant difference in change (p=0.43) or one-year post-operative (p=0.70) HRQoL, as measured by EQ-5D. There was also no significant difference in one-year patient satisfaction between groups (p=0.57). There was no significant difference in median LOS between groups (four days with ACB, four days with LA), although patients younger than 55 years undergoing ACB had a statistically significant median of one day reduced LOS compared with the LA group (p=0.01). Conclusions ACB when compared with LA alone was not associated with a difference in change in knee function, HRQoL, or patient satisfaction at one year following TKA. There was also no difference between groups in length of stay post-operatively. However, ACB was associated with a shorter length of stay in patients younger than 55, and this may be a group that would benefit from this intervention.

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.

Addition of infiltration between the popliteal artery and the capsule of the posterior knee (IPACK) to local infiltration analgesia for total knee arthroplasty: a prospective randomized controlled trial

BACKGROUND

Local infiltration analgesia (LIA) is a popular analgesic technique commonly administered during total knee arthroplasty (TKA). Recent studies have demonstrated that the infiltration between the popliteal artery and the capsule of the posterior knee (IPACK) can be complementary to analgesic modalities. However, the combined and relative efficacy of LIA and IPACK is unclear. We aimed to evaluate the analgesic and functional outcomes among LIA, IPACK, and LIA+IPACK.

MATERIALS AND METHODS

A total of 120 patients undergoing primary TKA were randomly allocated to 1 of 3 groups: LIA (50 mL of 0.25% ropivacaine and 2.0 μg/mL epinephrine); IPACK (20 mL of 0.25% ropivacaine and 2.0 μg/mL epinephrine); and LIA+IPACK. The primary outcome was the visual analog scale (VAS) pain score. Secondary outcomes were opioid use, knee range of motion (ROM), quadriceps muscle strength, mobilization distance, timed up and go (TUG) test, and postoperative complications.

RESULTS

The mean VAS pain scores were significantly higher after using IPACK alone than after using LIA+IPACK and LIA within 24 hours (all p＜0.05). LIA+IPACK had lower mean VAS pain scores than LIA when the knees were at rest (within 12 hours, p < 0.05) and flexion (within 8 hours, p＜0.05). Patients receiving LIA+IPACK and LIA had significantly lower morphine equivalents (ME) than those receiving IPACK alone within 24 hours (26.3, 28.9 versus 47.8, both p＜0.05) and during hospitalization (98, 101.6, versus 128.4 both p＜0.05). Both LIA+IPACK and LIA had higher ROM (within two days), higher level of muscle strength (within 12 hours), longer mobilization distances (within one day), and shorter TUG time (till discharge) compared with IPACK alone (all p＜0.05), while LIA+IPACK only had a higher knee ROM than LIA on the first postoperative day (p＜0.05). There was no significant difference in any other outcomes.

CONCLUSIONS

This randomized controlled trial demonstrated that there were significantly lower pain scores, less opioid consumption, and better functional results with LIA+IPACK and LIA when compared with IPACK alone, suggesting that IPACK alone was inferior for pain control.

The Ramifications of Opioid Utilization and Outcomes of Alternative Pain Control Strategies for Total Knee Arthroplasties

Morbidity and mortality related to opioid use has generated a public health crisis in the United States. Total knee arthroplasty (TKA) is an increasingly common procedure and is often accompanied by post-operative opioid utilization. Unfortunately, post-operative opioid usage after TKA has been shown to lead to higher rates of complications, longer hospital stays, increased costs, and more frequent need for revision surgery. Pre-operative opioid utilization has been shown to be one of the most important predictors of post-operative opioid usage. Additional risk factors for continued post-operative opioid utilization after TKA include pre-operative substance and tobacco use as well as higher post-operative prescription dosages, younger age, female gender, and Medicaid insurance. One method for mitigating excessive post-operative opioid utilization are Enhanced Recovery After Surgery (ERAS) protocols, which include a multidisciplinary approach that focuses on perioperative factors to optimize patient recovery and function after surgery. Additional strategies include multimodal pain regimens with epidural anesthetics, extended duration local anesthetics and adjuvants, and ultrasound guided peripheral nerve blocks. In recent years, opioid prescribing duration limitations have also been put into place by state and federal government, hospital systems, and ambulatory surgery centers making effective acute pain management imperative for all stakeholders. In this regard, as rates of TKA continue to increase across the United States, multidisciplinary efforts by all stakeholders are needed to ensure adequate pain control while preventing the negative sequalae of opioid medications.

Multimodal Analgesia

Perioperative pain management is one of the domains in which Anesthesiologists are intricately involved, and which is immensely important. Adequate postoperative analgesia is central to avoid both the acute as well as chronic complications of uncontrolled postoperative pain. Preventive analgesia has been identified as an approach to mitigate the phenomenon of central sensitization, which plays an important role in the development of chronic pain after surgery. As an over-reliance on opioids for peri- and postoperative pain control is associated with opioid dependence and hyperalgesia, multimodal analgesia has taken center stage. Multimodal analgesia, in theory, will optimize perioperative pain control, reduce the chance of central sensitization, and avoid the detrimental effects of opioid overuse. Multiple classes of systemic analgesic medications have been used to accomplish these tasks, and the aim of this article is to outline these medications, their mechanisms of action, as well as the evidence behind their individual roles in multimodal analgesia. Regional anesthesia has also been embraced as a key component of multimodal analgesia in orthopedic surgery; however, over the past several years, local infiltration analgesia (LIA) emerged as a viable alternative, particularly in total knee arthroplasty.

Pain management after total knee arthroplasty: PROcedure SPEcific Postoperative Pain ManagemenT recommendations

BACKGROUND

The PROSPECT (PROcedure SPEcific Postoperative Pain ManagemenT) Working Group is a global collaboration of surgeons and anaesthesiologists formulating procedure-specific recommendations for pain management after common operations. Total knee arthroplasty (TKA) is associated with significant postoperative pain that is difficult to treat. Nevertheless, pain control is essential for rehabilitation and to enhance recovery.

OBJECTIVE

To evaluate the available literature and develop recommendations for optimal pain management after unilateral primary TKA.

DESIGN

A narrative review based on published systematic reviews, using modified PROSPECT methodology.

DATA SOURCES

A literature search was performed in EMBASE, MEDLINE, PubMed and Cochrane Databases, between January 2014 and December 2020, for systematic reviews and meta-analyses evaluating analgesic interventions for pain management in patients undergoing TKA.

ELIGIBILITY CRITERIA

Each randomised controlled trial (RCT) included in the selected systematic reviews was critically evaluated and included only if met the PROSPECT requirements. Included studies were evaluated for clinically relevant differences in pain scores, use of nonopioid analgesics, such as paracetamol and nonsteroidal anti-inflammatory drugs and current clinical relevance.

RESULTS

A total of 151 systematic reviews were analysed, 106 RCTs met PROSPECT criteria. Paracetamol and nonsteroidal anti-inflammatory or cyclo-oxygenase-2-specific inhibitors are recommended. This should be combined with a single shot adductor canal block and peri-articular local infiltration analgesia together with a single intra-operative dose of intravenous dexamethasone. Intrathecal morphine (100 μg) may be considered in hospitalised patients only in rare situations when both adductor canal block and local infiltration analgesia are not possible. Opioids should be reserved as rescue analgesics in the postoperative period. Analgesic interventions that could not be recommended were also identified.

CONCLUSION

The present review identified an optimal analgesic regimen for unilateral primary TKA. Future studies to evaluate enhanced recovery programs and specific challenging patient groups are needed.

Ultrasound Guided Adductor Canal Block vs Intra Articular Analgesia for Post-operative Pain Relief after Arthroscopic Knee Surgeries: A Comparative Evaluation

Context and Aims:

Our aim was to assess the postoperative analgesia after ultrasound-guided “Adductor canal block” (ACB) and “Intraarticular Analgesia” (IAA) in arthroscopic knee surgeries postoperatively.

Settings and Design:

This experimental, randomized prospective study was conducted in the Department of Anesthesia, Himalayan Institute of Medical Sciences, Dehradun.

Subjects and Methods:

Sixty patients, who underwent arthroscopic knee surgeries were divided into two groups, with 30 patients each. Each group was given spinal anesthesia using 3 ml of 0.5% hyperbaric Bupivacaine. After completion of surgery, Group I patients were given ultrasound-guided ACB, Group II patients were given IAA. Postoperatively, pain was assessed using the Numeric Rating Scale (NRS). Time of first analgesic requirement and total postoperative tramadol consumption in the 1^st 24 h were recorded.

Results:

No significant difference was seen between both groups pertaining to patient's demographic data, type, and duration of surgery. The difference in the median NRS score between both the groups at different time intervals was statistically insignificant (P > 0.05). Total tramadol consumption in Group I (172.85 ± 82.59) mg was more than Group II (157.85 ± 33.83) mg. The duration of first analgesic requirement was 351.43 min, 342.86 min for Group I and II, respectively.

Conclusion:

To conclude, both ACB and IAA provide good postoperative pain control in arthroscopic knee surgeries with no significant difference in pain scores and postoperative analgesic requirement.

Comparison between Local Infiltration Analgesia and Ultrasound Guided Single Shot Adductor Canal Block Post Total Knee Replacement Surgery - A Randomized Controlled Trial

Context:

Good quality analgesia posttotal knee arthroplasty (TKA) contributes majorly to early mobilization and shorter hospital stay.

Aim:

To compare adductor canal block (ACB) versus local infiltration analgesia (LIA) for postoperative pain relief in patients undergoing TKA.

Settings and Design:

This prospective, single-blind, randomized controlled trial was undertaken at a tertiary care university hospital.

Materials and Methods:

Sixty patients of American Society of Anesthesiologists physical status Classes I, II, and III, who received spinal anesthesia for TKA were randomly allocated to two groups. Group A patients had LIA of the knee joint using a mixture of 50 mL of 0.25% bupivacaine, 10 mg morphine (1 mL) and 99 mL of normal saline. Group B patients received ACB using 25 mL of 0.5% bupivacaine under ultrasound guidance. All patients received multimodal analgesia comprising of paracetamol, diclofenac, and patient controlled analgesia with morphine in the first 24 h' postoperative period. The primary outcome measures were first 24 h' morphine consumption and pain scores at 4, 6, 8, 12, and 24 h. The secondary outcome measures were nausea/vomiting, sedation, and patient satisfaction scores.

Statistical Analysis:

Statistical analysis was performed using the Student's t-test, Mann–Whitney test, and Chi-square test.

Results:

The 24 h morphine consumption was 11.97 ± 7.97 and 10.83 ± 6.41 mg in the LIA group and ACB group, respectively (P = 0.54). No significant differences were noted either in the pain scores at rest and flexion or secondary outcome measures between both groups in the first 24 h.

Conclusion:

Single-shot ACB is equally effective as LIA as postoperative analgesia for TKA.

Reducing opioid usage in total knee arthroplasty postoperative pain management: a literature review and future directions

Total knee arthroplasty (TKA) is a common orthopedic surgery performed with a projected 3.5 million procedures to be done by 2030. Current postoperative pain management for TKA is insufficient, as it results in extensive opioid consumption and functional decline postoperatively. This study identifies the best practices for postoperative TKA pain management through a literature review of the last three years. Studies utilizing interventional techniques (local infiltration analgesia, nerve blocks) and pharmacologic options were reviewed on PubMed, Embase, Ovid Medline and Scopus. Primary outcomes analyzed were the effect of different analgesic approaches on pain reduction, opioid use reduction and improvements in functional mobility or quadriceps strength postoperatively. Additionally, this paper explores the use of cooled radiofrequency ablation, a minimally invasive therapy, for preoperative and postoperative TKA pain management.

Fascial plane blocks: a narrative review of the literature

Fascial plane blocks (FPBs) are increasingly numerous and are often touted as effective solutions to many perioperative challenges facing anesthesiologists. As 'new' FPBs are being described, questions regarding their effectiveness remain unanswered as appropriate studies are lacking and publications are often limited to case discussions or technical reports. It is often unclear if newly named FPBs truly represent a novel intervention with new indications, or if these new publications describe mere ultrasound facilitated modifications of existing techniques. Here, we present broad concepts and potential mechanisms of FPB. In addition, we discuss major FPBs of (1) the extremities (2) the posterior torso and (3) the anterior torso. The characteristics, indications and a brief summary of the literature on these blocks is included. Finally, we provide an estimate of the overall level of evidence currently supporting individual approaches as FPBs continue to rapidly evolve.

Comparison of Periarticular Injection and Intra-articular Injection for Pain Management After Total Knee Arthroplasty: A Systematic Review and Meta-Analysis

PURPOSE

Local infiltration analgesia, an essential component of multimodal analgesia after total knee arthroplasty (TKA), can be classified into periarticular injection (PAI) and intra-articular injection (IAI) as per administration techniques. Currently, there is no definite answer of the optimal choice between the two techniques. This meta-analysis aims to determine whether PAI provides superiority of pain relief and functional recovery than IAI after TKA.

DESIGN

Systematic review and meta-analysis.

METHODS

Comparative studies that compared PAI and IAI in patients after TKA were searched in the Embase, PubMed, MEDLINE, and the Cochrane Library databases. The primary outcomes were visual analog scale scores for pain and opioid consumption. The secondary outcomes were complications, function of recovery, and length of hospital stay.

FINDINGS

Four randomized controlled trials and two case-controlled studies with a total of 769 patients were enrolled. There were no significant differences in mean visual analog scale scores at postoperative day 0 (P = .17) and day 1 (P = .27), maximum visual analog scale scores at day 0 (P = .89) and day 1 (P = .82), total opioid consumption at day 1 (P = .96), opioid complications (P = .15), and length of hospital stay (P = .84) between PAI and IAI.

CONCLUSIONS

Based on the available evidence, PAI does not offer superior effects at pain control and discharge than IAI after TKA. However, owing to the limited sample size and heterogeneity of the included studies, further large well-designed randomized controlled trials are still needed to validate this conclusion.

REGISTRATION

The protocol has been registered in the PROSPERO international database under number CRD42020165138.

Adductor Canal Block Combined With iPACK (Interspace Between the Popliteal Artery and the Capsule of the Posterior Knee) Block vs Periarticular Injection for Analgesia After Total Knee Arthroplasty: A Randomized Noninferiority Trial

BACKGROUND

The combination of adductor canal block (ACB) and infiltration between the popliteal artery and the posterior capsule of the knee (iPACK) block may provide sufficient motor-sparing anterior and posterior knee analgesia after total knee arthroplasty. This study aimed to determine if ACB with iPACK block was noninferior to ACB with periarticular injection (PAI) when combined with postoperative multimodal analgesia regimen.

METHODS

Seventy-six patients were randomized to receive either ACB + iPACK block and continuous ACB (CACB) (ACB + iPACK group) or PAI and CACB (ACB + PAI group). Noninferiority was concluded for the primary outcome if the adjusted mean between-group difference in pain on movement at 12 postoperative hours was within 1.3 points on a visual analog pain scale. Pain scores, morphine consumption, functional performance, and adverse events were the secondary outcome measures assessed for superiority.

RESULTS

Adjusted mean differences, (ACB + iPACK) - (ACB + PAI), in anterior and posterior knee pain scores on movement at 12 postoperative hours were -0.66 (-1.86, 0.54) and -0.19 (-1.36, 0.99), respectively. The upper limit of 95% confident interval was lower than the prespecified noninferiority limit. The mean visual analog scale pain scores were low and no clinically significant differences between groups. However, morphine requirement at 48 postoperative hours was significantly higher (P < .05) and showed greater reduced quadriceps strength at 0 and 45 degrees on postoperative day 0 (P = .006 and .04, respectively) in the ACB + iPACK group.

CONCLUSIONS

ACB with iPACK block provides a noninferior analgesia compared with PAI when combined with CACB. However, patients who received ACB + iPACK block may require higher amounts of opioids and have worse immediate functional performance.

LEVEL OF EVIDENCE

Therapeutic level I.

Effect and safety of intravenous versus oral acetaminophen after unicompartmental knee replacement: A protocol of randomized controlled study

BACKGROUND

Due to the soft tissue injury and large amount of bone destruction involved, undesirable postoperative pain remains a challenge for both patients and surgeons after unicompartmental knee replacement (UKR). However, there are no studies comparing the effectiveness of oral and intravenous acetaminophen as part of a standard multimodal perioperative pain regimen after UKR. Thus, this prospective randomized study was conducted to compare pain control outcomes with postoperative oral versus intravenous acetaminophen use in adults undergoing UKR.

METHODS

The institutional review board of the Traditional Chinese Medicine- western Medicine Hospital of Cangzhou approved the study protocol. This blinded and randomized study was carried out in accordance with the principles of the Helsinki Declaration. We included patients who were scheduled for UKR with an American Society of Anesthesiologists status of I to III, who were mentally competent, and who were able to give consent for enrolment in the study. Patients were randomly assigned on a 1:1 basis to receive either intravenous acetaminophen or oral acetaminophen. We ensured that the patients, care providers, and outcome assessors were blinded to the group assignment during the study period. Primary outcomes were postoperative pain at rest and during motion (knee flexion of 45°) measured using a visual analog scale score. Secondary outcomes included morphine consumption at 24, 48, and 72 hours after surgery, length of hospital stay, range of motion, daily ambulation distance, and adverse events occurrence. All statistical analyses were performed using SPSS 25.0. Differences associated with a P value of <.05 were considered statistically significant.

RESULTS

It was hypothesized that patients receiving intravenous acetaminophen would exhibit similar postoperative outcomes compared with patients receiving oral acetaminophen.

TRIAL REGISTRATION

This study was registered in Research Registry (researchregistry5825).

Proximal versus distal adductor canal blocks for total knee arthroplasty: A protocol for randomized controlled trial

BACKGROUND

Currently, there remains a paucity of literature about the efficiency of proximal adductor canal block (PACB) versus distal adductor canal block (DACB) for pain management after total knee arthroplasty (TKA). The purpose of this study is to perform a randomized controlled trial to compare the efficiency of PACB versus DACB for early postoperative pain treatment after TKA.

METHODS

This study is a 2-arm, parallel-group, randomized controlled trial that is conducted at a single university hospital in China. Subjects presenting for unilateral TKA are randomized in a 1:1 ratio to either a PACB or DACB group. The primary outcome of this noninferiority study is opioid consumption within the first 24 hours following surgery. Secondary outcomes include quadriceps strength, pain scores, distance ambulated, and patient satisfaction. Continuous variables are compared using Student t test.

RESULTS

This clinical trial is expected to provide evidence of whether the PACB and DACB provide similar analgesia after TKA.

TRIAL REGISTRATION

This study protocol was registered in Research Registry (researchregistry5440).