Femoral Nerve Block and Adductor Canal Block

Achieving adequate pain control is vital for proper rehabilitation, satisfaction, and earlier discharge after anterior cruciate ligament reconstruction. Opioids have traditionally been used for this purpose, however, can be associated with various negative outcomes. As such, multimodal analgesia was introduced to reduce postoperative opioid use. Regional nerve blocks constitute one modality of multimodal analgesia, with femoral nerve blocks (FNBs) and adductor canal blocks (ACBs) being standard. This review sought to evaluate the utility and adverse effects of FNBs and ACBs relative to controls, alternative regional anesthesia options, and each other in pediatric or adolescent anterior cruciate ligament reconstruction (ACLR). Three databases were searched on January 31, 2024. The authors adhered to the PRISMA and R-AMSTAR guidelines and the Cochrane Handbook for Systematic Reviews of Interventions. The definition of pediatric was considered to be a mean age of 18 years or younger. Data on demographics, operative and anesthetic details, strength and functional outcomes, postoperative opioid consumption, revision rates and return to sport (RTS) rates, and Visual Analogue Scale (VAS) scores were extracted. Eleven studies (1 level I, 10 level III) comprising 5453 patients were included in this review (54.1% female), with a mean age of 16.3 (range of means: 15.0 to 16.9) years. Two studies compared FNB with and without a sciatic-nerve block (SNB), finding lower opioid consumption ( P =0.007) and VAS scores ( P <0.0001) in the postanesthesia care unit (PACU) in the FNB + SNB group. Three studies compared FNB or ACB with controls, with no studies reporting a benefit in rates of RTS, isokinetic quadriceps or hamstrings strength, or functional test performance. There were minimal differences when comparing continuous and single nerve blocks and FNB with ACB. There is inconclusive evidence investigating the role of FNB and ACB in pediatric or adolescent ACLR. The addition of a SNB to FNB may result in improvements in opioid consumption and VAS scores in the early postoperative period. There was minimal evidence in support of continuous blocks over single-shot blocks. Future studies should compare the use of ACB, FNB, and no blocks for pediatric or adolescent ACLR, with primary endpoints of acute pain control, postoperative opioid use, and the presence of longer-term motor deficits. Level III.

Effective perioperative pain control following knee arthroscopy allows patients to reduce narcotic intake, avoid side effects of these medications, and recover more quickly. Adductor canal nerve blockade (ACB) and intra-articular injection of local anesthetic have been described as adjuvant treatments for postoperative pain control following surgery of the knee. This study directly compares the effect of each of these treatment modalities. Patients undergoing knee arthroscopy were blinded and randomized to receive either an ACB (n&#x2009;=&#x2009;60) or intra-articular injection of local anesthetic (IAB, n&#x2009;=&#x2009;64). Outcome measures included patient reported visual analog scale (VAS) scores at 1, 2, 4, 8, 16, 24, 36, 48&#x2009;hours and 1 week and total narcotic consumption at 12, 24, and 48&#x2009;hours postoperatively. Student's t-tests were used to compare unadjusted VAS scores at each time point and use of postoperative pain medication between treatment groups. Adjusted VAS scores were estimated in a multivariable general linear model with interaction of time and treatment group and other relevant covariates. There were no statistically significant differences between the two groups in terms of gender, age, body mass index, and insurance type. ACB patients had significantly higher pain scores than IAB patients at hours 1 and 2 (hour 1: 4.02 [2.99] vs. 2.59 [3.00], p&#x2009;=&#x2009;0.009; hour 2: 3.12 [2.44] vs. 2.17 [2.62], p&#x2009;=&#x2009;0.040). ACB patients had higher pain scores than IAB patients up to hour 16, though hours 4 to 16 were not significantly different. Adjusted covariate analyses demonstrate an additional statistically significant reduction in pain score in the IAB group at hour 4. There were no differences in narcotic consumption. Intraoperative local anesthetic and regional ACB each provides adequate pain control following knee arthroscopy, and intraoperative local anesthetic may provide enhanced pain control for up to 4&#x2009;hours postoperatively. LEVEL OF EVIDENCE: : Level 1 evidence, randomized control trial.

The quality of postoperative analgesia in total knee arthroplasty is crucial for patient recovery, rehabilitation, and hospital stay duration. In line with the above, &#x430; single-shot adductor canal block has been considered as an improved method over continuous femoral nerve block. However, continuous adductor canal block and single-shot femoral nerve block have been not adequately addressed in the discussion. This study aimed to compare the effectiveness of various types of adductor and femoral nerve blocks on clinically relevant outcomes in patients following total knee arthroplasty. A systematic review and network meta-analysis were conducted following "PRISMA-NMA" and Cochrane Handbook guidelines. The eligibility criteria included randomized trials and, where these were lacking for a comparison, nonrandomized studies involving adults undergoing primary total knee arthroplasty, comparing single-shot adductor canal block, continuous adductor canal block, single-shot femoral nerve block, and continuous femoral nerve block. A total of 36 studies involving 3308 patients were included. Single-shot adductor canal block showed higher pain scores and opioid consumption but better functional recovery at 24&#xa0;h compared with continuous femoral nerve block. However, this trend vanishes by the 48&#xa0;h assessment postsurgery. Continuous adductor canal block required higher opioid consumption but better functional recovery and shorter hospital stay compared with continuous femoral nerve block. Single-shot adductor canal block showed higher pain scores but comparable opioid consumption and functional recovery to continuous adductor canal block. The shift from continuous femoral nerve block to single-shot adductor canal block as the preferred method for pain relief after total knee arthroplasty may be premature. While the latter improves mobility, it falls short in pain control and does not shorten hospital stays. Continuous adductor canal block shows promise but is currently underappreciated, and single-shot femoral nerve block is often overshadowed by other techniques in regional anesthesia. Further high-quality, multicenter randomized controlled trials are needed to validate these findings.

The optimal pain management strategy for postoperative pain after anterior cruciate ligament reconstruction (ACLR) remains unclear. This study compared femoral nerve block (FNB) and adductor canal block (ACB) for pain management of early postoperative pain, knee function, and recovery of activity of daily living (ADL) after ACLR using hamstring autografts. In this prospective, single-blind, randomised controlled trial, 64 patients aged 12-56&#xa0;years who underwent anatomical double-bundle ACLR with a hamstring autograft between August 2019 and May 2020 were randomised to undergo preoperative FNB (n&#x2009;=&#x2009;32) or ACB (n&#x2009;=&#x2009;32). The peripheral nerve block was performed by a single experienced anaesthesiologist under ultrasound guidance. The primary outcomes were postoperative pain as evaluated using the visual analogue scale (VAS) at 3, 6, 12, 24, and 48&#xa0;h postoperatively and the need for pain relief. The secondary outcome was knee function, including the recovery of range of motion, contraction of the vastus medialis, and stable walking with a double-crutch (ADL), as evaluated by blinded physical therapists. There were no significant differences in patient demographics between the two groups. The VAS scores, need for pain relief, knee function, and ADL did not significantly differ between the groups. FNB and ACB provided comparable outcomes related to early postoperative pain, knee function, and ADL after double-bundle ACLR using hamstring autografts. Further research is necessary to evaluate the mid- to long-term effect of each block on recovery of knee function and ADL. I.

Continuous adductor canal block (CACB) is almost a pure sensory nerve block and can provide effective analgesia without blocking the motor branch of the femoral nerve. Thus, the objective of this study was to systematically evaluate the efficacy of CACB versus continuous femoral nerve block (CFNB) on analgesia and functional activities in patients undergoing knee arthroplasty. PubMed, Embase and the Cochrane Central Register of Controlled Trials (from inception to 3 October 2023) were searched for randomized controlled trials (RCTs) that compared CACB with CFNB in patients undergoing knee arthroplasty. Registration in the PROSPERO International prospective register of the meta-analysis was completed, prior to initiation of the study (registration number: CRD42022363756). Two independent reviewers selected the studies, extracted data and evaluated risk of bias by quality assessment. Revman 5.4 software was used for meta-analysis and the summary effect measure were calculated by mean differences and 95% confidence intervals. Eleven studies with a total of 748 patients were finally included. Pooled analysis suggested that both CACB and CFNB showed the same degree of pain relief at rest and at motion at 12 h, 24 h and 48 h in patients undergoing knee arthroplasty. Compared with CFNB, CACB preserved the quadriceps muscle strength better (P<0.05) and significantly shortened the discharge readiness time (P<0.05). In addition, there was no significant difference in opioid consumption, knee extension and flexion, timed up and go (TUG) test, or risk of falls between the two groups. Thus, Compared with CFNB, CACB has similar effects on pain relief both at rest and at motion and opioid consumption for patients undergoing knee arthroplasty, while CACB is better than CFNB in preserving quadriceps muscle strength and shortening the discharge readiness time.

A Bayesian network meta-analysis was performed to compare the analgesic efficacy of the following nerve block techniques: femoral nerve block (FNB), adductor canal block (ACB), infiltration between the popliteal artery and the capsule of the posterior knee (iPACK), and genicular nerve block (GNB) following total knee arthroplasty (TKA). Systematic review and network meta-analysis (NMA). We searched the Web of Science, PubMed, EMBASE, and Cochrane Library databases until September 20, 2022. Patients who were treated by any of the above four nerve block techniques (alone or in combination) after TKA were included. Patients who underwent minimally invasive knee surgery were excluded. The indicators included pain scores during rest and mobilization, opioid consumption after surgery, postsurgical mobilization function (ROM [range of motion], TUG [Timed-Up-and-Go] test) at 24&#xa0;h and 48&#xa0;h, and length of hospital stay. The risk of bias was assessed by the Cochrane risk of bias tool. Forty-two studies involving 2857 patients were eligible for this study. This NMA suggested that ACB&#xa0;+&#xa0;iPACK was the most efficacious option for improving ambulation ability and shortening the length of hospital stay. Furthermore, ACB&#xa0;+&#xa0;iPACK was the best regimen for resting-pain and movement-pain relief (78% and 87%, respectively) and for reducing opioid consumption (90%) at 48&#xa0;h. However, FNB&#xa0;+&#xa0;iPACK was the most efficacious option for relief of resting pain (42%) and reducing opioid consumption (68%) at 24&#xa0;h; GNB was the most efficacious option for movement pain relief at 24&#xa0;h (94%). Considering both pain control and knee functional recovery, ACB&#xa0;+&#xa0;iPACK may be the optimal analgesic regimen for patients after TKA. At the same time, it significantly reduces pain and opioid consumption at 48&#xa0;h. However, ACB&#xa0;+&#xa0;iPACK is not the recommended technique for short-term (24&#xa0;h) pain control. PROSPERO (CRD42022362322).

Previous studies comparing adductor canal block (ACB) with femoral nerve block (FNB) are inconclusive with regard to patient-controlled analgesia (PCA) induced by opioids. Moreover, some postoperative pain severity results differ between previous randomized controlled trials (RCTs). The primary aim of the current study was to compare total intravenous morphine consumption administered via PCA during the first postoperative day in continuous FNB and ACB groups after total knee arthroplasty (TKA). Secondary aims included evaluation of postoperative pain via a visual analog scale, degree of knee extension, quadriceps muscle strength, and ability to sit, stand upright, and walk. The study was a RCT. Inclusion criteria were presence of gonarthrosis, age >18 and <75 years, and scheduled for TKA under single-shot spinal anesthesia. A number of morphine uses was lower in the FNB group than in the ACB group (14, range 12-15 vs 20, range 18-22; P&#x200a;=&#x200a;.0001), and they perceived less severe pain at the 8th (P&#x200a;=&#x200a;.00003) and 24th hours. However, ACB was significantly superior with regard to most of the other parameters pertaining to mobility, including muscle strength at the 8th and 24th hours, degree of knee extension at the 8th hour, sitting at the 8th hour, standing upright at the 24th hour, and walking at the 24th and 48th hours. FNB was associated with the perception of less severe pain after TKAs. However, ACB was associated with earlier mobility rehabilitation.