Analgesic Impact of a Popliteal Plexus Block to Standard Adductor Canal Block in Arthroscopic Anterior Cruciate Ligament Reconstruction: A Randomized Blind Clinical Trial

Background. Damage to the anterior cruciate ligament (ACL) is crippling and often requires an arthroscopic outpatient surgery. Nevertheless, many patients experience severe pain during the first day after ACL reconstruction (ACLR). The adductor canal block (ACB) has yielded conflicting results for post-ACLR pain relief. This research investigated the effect of a supplemental popliteal plexus block on postoperative pain outcomes compared to a sole ACB. Methods. Following a randomized design, 60 cases scheduled for knee arthroscopy with ACLR using an ipsilateral hamstring graft were separated into two categories. Subjects in group A (n = 30) received an ACB only, while subjects in group B (n = 30) received combined ACB and popliteal plexus block (PPB). Results. We found significant differences between the two groups. The time of the first analgesic request (TFR) was later for the combined ACB and PPB (median 8 h) compared to the ACB only group (median 0.5 h). Morphine consumption was lower for patients who received combined ACB and PPB (median 12 mg) compared to ACB only (median 30 mg). The number of the requested doses was lower for the combined ACB and PPB group (median 3 doses) compared to the ACB only group (median 7 doses). Conclusions. The addition of PPB to ACB was associated with improved analgesia and a reduced need for opioid-based sedatives following ACLR with an ipsilateral hamstring graft (https://clinicaltrials.gov/ct2/show/NCT04020133).

Analgesic efficacy of single-shot adductor canal block versus adductor canal block combined with intra-articular ropivacaine infusion after total knee arthroplasty

Aims Single-shot adductor canal block (ACB) after total knee arthroplasty (TKA) for postoperative analgesia is a common modality. Patients can experience breakthrough pain when the effect of ACB wears off. Local anaesthetic infusion through an intra-articular catheter (IAC) can help manage breakthrough pain after TKA. We hypothesized that combined ACB with ropivacaine infusion through IAC is associated with better pain relief compared to ACB used alone. Methods This study was a prospective double-blinded placebo-controlled randomized controlled trial to compare the efficacy of combined ACB+ IAC-ropivacaine infusion (study group, n = 68) versus single-shot ACB+ intra-articular normal saline placebo (control group, n = 66) after primary TKA. The primary outcome was assessment of pain, using the visual analogue scale (VAS) recorded at 6, 12, 24, and 48 hours after surgery. Secondary outcomes included active knee ROM 48 hours after surgery and additional requirement of analgesia for breakthrough pain. Results The study group (mean visual analogue scale (VAS) pain score of 5.5 (SD 0.889)) experienced significant reduction in pain 12 hours after surgery compared to the control group (mean VAS 6.62 (SD 1.356); mean difference = 1.12, 95% confidence interval (CI) -1.46 to 0.67; p < 0.001), and pain scores on postoperative day (POD) 1 and POD-2 were lower in the study group compared to the control group (mean difference in VAS pain = 1.04 (-1.39 to -0.68, 95% CI, p < 0.001). Fewer patients in the study group (0 vs 3 in the control group) required additional analgesia for breakthrough pain, but this was not statistically significant. The study group had significantly increased active knee flexion (mean flexion 86.4° (SD 7.22°)), compared to the control group (mean 73.86° (SD 7.88°), mean difference = 12.54, 95% CI 9.97 to 15.1; p < 0.014). Conclusion Combined ACB+ ropivacaine infusion via IAC is a safe, reproducible analgesic modality after primary TKA, with superior analgesia compared to ACB alone. Further large volume trials are warranted to generate evidence on clinical significance on analgesia after TKA. Cite this article: Bone Jt Open 2021;2(12):1082–1088.

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: One option in total knee arthroplasty (TKA) perioperative pain management is femoral nerve block (FNB). Its association with quadriceps weakness has led to a focus on adductor canal block (ACB), with the aim of avoiding weakness in adjacent muscles. This study reviewed cases at our institution. Methods: In this pilot non-blinded study, nerve block (FNB or ACB) was performed under ultrasonic guidance after induction of general anesthesia, with an initial bolus followed by continuous levobupivacaine infusion into the perineurium as needed 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 had been able to ambulate on POD 1, was investigated. Results: A total of 73 TKA cases, 37 FNB and 36 ACB, met the inclusion criteria. Episodes of near-falls in the form of knee-buckling were witnessed in 14 (38%) cases in the FNB group and in 4 (11%) in the ACB group (p = 0.0068). In the ACB group, 81.1% of patients were able to ambulate with parallel bars on POD 1, while only 44.4% of FNB patients could do so (p = 0.0019). The quadriceps MMT values of patients able to ambulate with parallel bars on POD 1 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) through POD 3. Conclusion: Compared to FNB, ACB was associated with significantly less knee-buckling and earlier initiation of ambulation post-TKA, with better quadriceps muscle strength. These findings support the use of ACB as the anesthesia method of choice for TKA.

Additional nerve blocks are not superior to multiple-site infiltration analgesia in total knee arthroplasty under adductor canal block

Background Adductor canal block (ACB) with additional nerve blocks (ANBs) is reported to provide adequate analgesia and enhanced functional rehabilitation in total knee arthroplasty (TKA). The present study aims to evaluate whether ANBs are superior to multiple-site infiltration analgesia (MIA) in patients undergoing TKA under ACB. Methods We enrolled 530 patients undergoing primary TKA from 2015 to 2019 at our institution in this retrospective cohort study. Patients were divided into two groups: Group A was treated with ANBs + ACB; Group B was treated with MIA + ACB. Primary outcomes were pain scores and morphine consumption. Functional recovery was the secondary outcome. Other outcomes included satisfaction score, cost-effectiveness, adverse events, and length of hospital stay (LOS). Results Pain scores at rest and morphine consumption were slightly lower in the ANBs + ACB group than in the MIA + ACB group. No significant difference was found in functional recovery, post-operative complications or LOS between the groups. Meanwhile, the cost of analgesic intervention in the MIA + ACB group was less than that in the ANBs + ACB group. Conclusion The present study suggests that ANBs do not provide superior pain relief compared to MIA for patients undergoing TKA under ACB. Trial registration Chinese Clinical Trial Registry, ChiCTR2100043227. Registered 9 February 2021, https://www.chictr.org.cn/showproj.aspx?proj=121745.

Does the Addition of iPACK Block to Adductor Canal Block Provide Improved Analgesic Effect in Total Knee Arthroplasty? A Systematic Review and Meta-Analysis

The interspace between popliteal artery and the capsule of posterior knee (iPACK) block was proposed in recent years to relieve posterior knee pain. Since adductor canal block (ACB) and iPACK involve different branches of the sensory nerves, it is theoretically feasible to combine iPACK block and ACB to relief pain after total knee arthroplasty (TKA). We aim to validate the efficacy of adding iPACK block to ACB in the setting of a multimodal pain management protocol following TKA. A comprehensive literature review on Web of Science, Embase, the Cochrane Library, and PubMed was performed. Eight studies (N = 1,056) that compared the efficacy of iPACK block + ACB with ACB alone were included. Primary outcomes consisted of Visual Analogue Scale (VAS) score at rest or during activity at various time points. Secondary outcomes include opioids consumption, walking distance, and length of hospital stay (LOS). Compared to ACB alone, VAS scores at rest (standardized mean difference [SMD]: –1.18; 95% confidence interval [CI]: –2.05 to –0.30) and during activity (SMD: –0.26; 95% CI: –0.49 to –0.03) on the day of surgery were lower in the iPACK block + ACB group. However, the difference did not reach the minimal clinically important difference. Opioids consumption at postoperative 24 hours was lower in the iPACK + ACB group (SMD: –0.295; 95% CI: –0.543 to –0.048). VAS score on postoperative day (POD) 1 and POD2, opioids consumption from 24 to 48 hours, walking distance, and LOS were not different. In conclusion, the addition of iPACK block to ACB in a multimodal pain management protocol can effectively reduce opioids consumption in the early postoperative period. This is a level III, meta-analysis study.