Block In Total Knee Arthroplasty Research Articles

Evaluation of Postoperative Pain When Adding a Tibial Nerve Block to the Femoral Nerve Block for Total Knee Arthroplasty

Background: The aim of this study was to compare the postoperative analgesic efficacy when a tibial nerve block was added to the femoral nerve block for total knee arthroplasty (TKA). Methods: A total of 60 patients were randomly assigned to the experimental group (EG) or the control group (CG) in a 1:1 ratio. The thirty patients who formed the CG underwent an ultrasound-guided femoral nerve block together with neuraxial anaesthesia and the administration of opioids and NSAIDs through an intravenous elastomeric pump for the management of the postoperative pain; the other thirty, who formed the EG, underwent neuraxial anaesthesia together with femoral and tibial nerve blocks. The efficacy of the analgesic effect was evaluated based on the numerical pain rating scale (NPRS) and on the need for analgesic rescue at different time intervals within 48 h after surgery. Results: At 24 h, the mean NPRS score in the EG and CG at rest was 1.50 ± 1.19 and 1.63 ± 1.60 [U = 443.5, p = 0.113], respectively. With joint movement, the mean NPRS score was 2.80 ± 1.49 and 3.57 ± 1.79 [U = 345, p = 0.113], respectively. Ten patients in the EG [33.3%] and 24 in the CG [80%] required rescue analgesia [Phi = 0.471, p < 0.001]. At 48 h, the mean NPRS score in the EG and CG at rest was 0.33 ± 0.60 and 0.43 ± 0.72 [U = 428, p = 0.681], respectively. With movement, the mean NPRS score was 1.03 ± 0.99 in the EG and 1.60 ± 1.07 in the CG [U = 315, p = 0.038]. No patient in the EG group required rescue analgesia, while three patients in the CG [10%] did [Phi = 0.229, p = 0.076]. The mean opioid dosage in the CG was 300 mg, whereas in the EG it was 40 mg ± 62.14 [U < 0.05, p < 0.001]. Conclusions: Adding a tibial nerve block to the femoral nerve block in TKA may achieve the same analgesic efficacy within 48 h after surgery and would reduce the systematic use of opioids.

Sublingual sufentanil tablet system (SSTS) versus a single shot peri-nervous injection of ropivacaine for the management of postoperative pain after total knee arthroplasty: a single-center randomized trial.

For several years, ropivacaine has been the standard-of-care for establishing postoperative femoral nerve block in total knee arthroplasty (TKA) setting and is still widely in use but new approaches such as the patient-controlled administration of sublingual sufentanil tablets system (SSTS) seem to offer good clinical results. Our aim is to compare the SSTS to single shot peri-nervous injection of ropivacaine (single shot) after TKA in terms of effectiveness in pain management and of time to recovery. A total of 165 patients undergoing TKA were enrolled. Eighty-four patients were randomly allocated in the SSTS group and 81 patients in the single shot group. The primary objective of the study was to evaluate performance of Timed Up and Go test. Secondary objectives were to measure the length of stay, NRS pain scale, the adherence to the prescribed plan, the joint mobility, the frequency of rescue analgesic use, side effects and patients' satisfaction. Of all patients of the single shot group, 64 were withdrawn from the study as they unable to achieve pain control; only one patient was withdrawn from the SSTS group. Times for the "Timed Up and Go" test on the 3rd postoperative day were 8.4 ± 1.6 and 11.8 ± 3.6 in the SSTS group (n = 83) and single shot group (n = 17), respectively (p < .001). SSTS provides better pain management when compared to peri-nervous ropivacaine single shot injection after TKA.

A direct saphenous nerve block in TKA: A surgeon friendly technique! Cadaveric study

IntroductionEffective management of postoperative pain in total knee arthroplasty (TKA) poses a significant challenge for surgeons. Achieving rapid recovery without pain and promoting early ambulation in immediate and early postoperative periods are essential for patient satisfaction. There are many pain management protocols including nerve blocks. Nerve blocks procedures were done using USG and anaesthetist dependent. This cadaveric study aimed to define the VMO (Vastus medialis obliquus) triangle to target the ‘safe zone’ of the saphenous nerve during TKA: A surgeon's friendly technique. Methods12 formalin-fixed embalmed cadaveric lower limbs were dissected to explore anatomy, trajectory, the relation of saphenous nerve and measured the distances from the nearby palpable bony landmarks. ResultsThe average distance to target the saphenous nerve i.e target point from midpoint of superior pole of the patella was 10.6cm, the average angle to target the saphenous nerve is the angle between the line joining the medial epicondyle to the midpoint of the superior pole of the patella is found to be 64.2°. The average distance from midpoint of superior pole patella to medial epicondyle is found to be 8.1cm. Therefore, triangle so formed using these three points (1. Medial epicondyle, 2. The midpoint of superior pole of the patella, 3. Target point of the saphenous nerve) is called a VMO triangle. ConclusionsThe saphenous nerve course, relations, and the distances from intraoperative bony landmarks for the VMO triangle during TKA which is a reproducible triangle so may be useful for arthroplasty surgeons to achieve successful saphenous nerve block and to avoid related complications during total knee arthroplasty (TKA).

Adductor Canal Block Versus Femoral Nerve Block in Total Knee Arthroplasty: Network Meta-Analysis.

The quality of postoperative analgesia in total knee arthroplasty is crucial for patient recovery, rehabilitation, and hospital stay duration. In line with the above, а 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 24h compared with continuous femoral nerve block. However, this trend vanishes by the 48h 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.

Periarticular Infiltration Compared to Single Femoral Nerve Block in Total Knee Arthroplasty: A Prospective Randomized Study.

Objective To compare patients undergoing total knee arthroplasty (TKA) under spinal anesthesia and single femoral nerve block (FNB) with subjects undergoing TKA under spinal anesthesia and periarticular infiltration (PAI). Materials and Methods A total of 100 patients undergoing primary TKA were randomized into two groups. Group 1 included patients undergoing surgery under FNB associated with spinal anesthesia, while group 2 included patients undergoing TKA under IPA and spinal anesthesia. The assessment of these subjects in the early postoperative period included pain, active flexion, active extension, elevation of the extended limb, and morphine use. Results There was no significant difference in the types of analgesia concerning pain, the elevation of the extended limb, and morphine use. Active flexion and extension were better in the PAI group ( p = 0.04 and p = 0.02 respectively). Conclusion We conclude that the techniques are similar regarding pain control, limb elevation, and morphine use. The use of IPA provided better active flexion and extension during the hospital stay compared to single FNB in patients undergoing TKA.

Tibial-IPAC block is a new addition to femoral-IPACK block in total knee arthroplasty.

Tibial-IPAC block is a new addition to femoral-IPACK block in total knee arthroplasty.

Pain Management, Functional Recovery, and Stress Response Expressed by NLR and PLR after the iPACK Block Combined with Adductor Canal Block for Total Knee Arthroplasty-A Prospective, Randomised, Double-Blinded Clinical Trial.

This study aimed to investigate pain management, functional recovery, and stress response expressed by the neutrophile-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) after the popliteal artery and posterior knee capsule infiltration (iPACK) block combined with adductor canal block (ACB) in total knee arthroplasty (TKA). This was a prospective, double-blinded, randomised, controlled trial in a tertiary referral hospital. Three hundred and sixty-six patients were randomly allocated into the sham block group and iPACK combined with the ACB group. The primary outcome was postoperative pain scores. The secondary outcomes were opioid consumption, functional recovery expressed by a range of motion, and quadriceps strength. Also, the neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) were calculated. There were significant differences between the sham block and iPACK + ACB group in pain scores p < 0.0001 at all time points. Therefore, there was a significant difference in opioid consumption (p < 0.0001) and functional recovery (p < 0.0001). Also, NLR and PLR levels 12 h (p < 0.0001) and 24 h (24 h) after surgery (p < 0.0001) were much lower in the iPACK + ACB group. After total knee arthroplasty, the iPACK combined with ACB block group improved pain management, functional recovery, and stress response. Therefore, we strongly recommend this technique as a part of a multimodal analgesia protocol in knee surgery.

Early versus delayed postoperative adductor canal block in total knee arthroplasty.

We hypothesized that patients who received an adductor canal block (ACB) in the operating room following unilateral total knee arthroplasty would have a lower oral morphine milligram equivalent (MME) consumption during the postanesthesia care unit (PACU) phase 1 recovery period compared to patients who received an ACB in the PACU. This was a retrospective cohort study of patients who underwent robotic-assisted unilateral total knee arthroplasty under general anesthesia between March 1, 2020, and February 28, 2021, and received postoperative ACB either in the operating room or the PACU. A total of 36 and 178 patients received postoperative ACB in the operating room and PACU, respectively, and had median and interquartile range MME consumption in the PACU of 22.5 (20-40) mg and 30.0 (20-40) mg (P = 0.76), respectively. Patients who had an ACB performed in the operating room and PACU had median and interquartile ranges of time spent in the PACU of 101 (75-178) minutes and 186 (125-272) minutes (P < 0.01), respectively. Patients who received an ACB in the operating room did not have a lower OME consumption than patients who received an ACB in the PACU but did have a shorter PACU length of stay.

Analgesic Effectiveness of Motor-sparing Nerve Blocks for Total Knee Arthroplasty: A Network Meta-analysis.

The analgesic effectiveness of contemporary motor-sparing nerve blocks used in combination for analgesia in total knee arthroplasty is unclear. This network meta-analysis was conducted to evaluate the analgesic effectiveness of adding single-injection or continuous adductor canal block (ACB) with or without infiltration of the interspace between the popliteal artery and the capsule of the posterior knee (iPACK) to intraoperative local infiltration analgesia (LIA), compared to LIA alone, after total knee arthroplasty. Randomized trials examining the addition of single-injection or continuous ACB with or without single-injection block at the iPACK to LIA for total knee arthroplasty were considered. The two primary outcomes were area-under-the-curve pain scores over 24 to 48 h and postoperative function at greater than 24 h. Secondary outcomes included rest pain scores at 0, 6, 12, and 24 h; opioid consumption (from 0 to 24 h and from 25 to 48 h); and incidence of nausea/vomiting. Network meta-analysis was conducted using a frequentist approach. A total of 27 studies (2,317 patients) investigating the addition of (1) single-injection ACB, (2) continuous ACB, (3) single-injection ACB and single-injection block at the iPACK, and (4) continuous ACB and single-injection block at the iPACK to LIA, as compared to LIA alone, were included. For area-under-the-curve 24- to 48-h pain, the addition of continuous ACB with single-injection block at the iPACK displayed the highest P-score probability (89%) of being most effective for pain control. The addition of continuous ACB without single-injection block at the iPACK displayed the highest P-score probability (87%) of being most effective for postoperative function. The results suggest that continuous ACB, but not single-injection ACB and/or single-injection block at the iPACK, provides statistically superior analgesia when added to LIA for total knee arthroplasty compared to LIA alone. However, the magnitude of these additional analgesic benefits is clinically questionable.

Preliminary experience on systemic effects of perineural dexamethasone sodium phosphate and methylprednisolone acetate through adductor canal block in total knee arthroplasty: A single center retrospective study.

Glucocorticoids are commonly utilised as adjuvants to enhance nerve block quality and prolong the analgesic duration. Its systemic effects, after a single-injection adductor canal block (ACB) followed by a continuous infusion, are unclear. The aim of the study was to assess the systemic effects of a single dose of dexamethasone sodium phosphate (DEX), or a combination of DEX and methylprednisolone acetate (MPA), on fasting blood glucose (FBG) and white blood cell count (WBC) when administered perineurally via ACB. A single-center retrospective study on total knee arthroplasty (TKA) was performed and a total of 95 patients were included in the final analysis. Patients were divided into three groups based on adjuvants received in ACB: Control group (N = 41) and two treatment groups, DEX group (N = 33) and DEX/MPA group (N = 21). Our primary outcomes were the change of FBG from its preoperative baseline value on postoperative day (POD) 2. The secondary outcomes included change of FBG on POD 0 and POD 1, and change of WBC on POD 0, POD 1, and POD 2. The FBG change from baseline in the DEX group was significantly higher than that in the control group (difference = 14.04, 95% CI: 1.3 to 26.77), P = 0.031) on POD 0. The WBC change from baseline in the DEX/MPA group was statistically significant higher than control on POD 0 (2.62 (1.52 to 3.37), P < 0.0001). No significant differences between DEX and DEX/MPA group were found on any given postoperative days for FBG and WBC. This study provided preliminary safety data on the use of a combination of glucocorticoids with hydrophilic (DEX) and lipophilic (MPA) properties as local anesthetic adjuvants in ACB, which induced similar levels of changes on FBG and WBC as those from both control and DEX alone group.

Comparison of adductor canal block, peri–articular injection or infiltration between popliteal artery and posterior knee capsule with adductor canal block in total knee arthroplasty

Background: Moderate to severe postoperative pain is experienced by patients after total knee arthroplasty (TKA), which has an impact on postoperative rehabilitation, patient satisfaction, and overall results. Aim: Patients receiving total knee arthroplasty under general anesthesia were evaluated to see how well the combined adductor canal block and infiltration of the interspace between popliteal artery and the capsule of posterior knee block (IPACK) reduced post-operative discomfort. These treatments were compared to adductor canal block (ACB) and peri-articular injections alone (PAIs). Patients and methods: 60 patients were randomly allocated into three groups (20 in each). All that Group I patients got was an adductor block. Patients in Group II only received the periarticular injection. The IPACK (interspace between popliteal artery and posterior knee capsule) block and adductor block procedures were performed on patients in Group III. The Numeric Rating Scale (NRS) was used to measure post-operative pain as the primary endpoint both during physical therapy and when the patient was at rest. Mobilization was assisted by the Timed Up-and-Go (TUG) and MRC tests, and the second objective was postoperative analgesia, which was assessed by the total number of analgesics used and the time it took until the first rescue analgesic was delivered. Results: The total amount of morphine consumed in IQR amongst the three study groups was statistically different (p-value 0.005). Total postoperative morphine consumption in groups II and III was statistically significantly lower than in groups I (p-value 0.005), and there was also a significant difference between groups II and III (p-value 0.005), indicating that group II had significantly less total morphine consumption than the other two groups. Conclusion: In contrast to combination IPACK-ACB and ACB alone, we came to the conclusion that adding PAIs to the pain management regimen for patients having TKA enhances analgesia quality and reduces opioid intake. Even though the combined IPACK-ACB block was less successful than PAIs, it nevertheless showed superior pain scores at rest and during physiotherapy and required less opioid consumption than ACB alone, making it a viable option to PAIs in situations where this technique is not practical.

Retracted: Application of General Anesthesia Combined with Saphenous Nerve-Tibial Nerve Block in Total Knee Arthroplasty.

[This retracts the article DOI: 10.1155/2022/7010492.].

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

BackgroundNear-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.MethodsContinuous 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.ResultsA 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.ConclusionACB 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.

Application of General Anesthesia Combined with Saphenous Nerve-Tibial Nerve Block in Total Knee Arthroplasty.

Background The study aimed to evaluate the safety and efficiency of the saphenous nerve plus selective tibial nerve block combined with general anesthesia in total knee replacement surgery (TKRS). Methods Sixty-four patients who underwent unilateral TKRS between October 2019 and June 2020 were selected as study subjects. All patients were divided into the control and observation groups using the random number table method, with 32 patients in each group. Conventional general anesthesia was performed preoperatively in both groups. The control group was given an ultrasound-guided saphenous nerve block before anesthesia induction, and the observation group was given a selective tibial nerve block on the basis of the control group. The dosage of general anesthetic drugs, recovery time from general anesthesia, hemodynamic index, inflammatory response, postoperative analgesic effect, and adverse reaction rate were compared between the two groups. Results Compared with the control group, the total amount of propofol and remifentanil used in the observation group was significantly less (P < 0.05). Compared with the control group, patients in the observation group experienced remarkably shorter time to recovery from respiration, time to extubation, and time in the PACU (P < 0.05). Compared with the control group, the observation group showed a significantly reduced SBP and MAP at T2, T3, and T4, respectively, and also showed a prominently lower HR at T3 and T4 (P < 0.05). Markedly lower CRP and IL-6 levels at 6 h and 24 h after surgery were found in the observation group compared to the control group (P < 0.05). Compared with the control group, patients receiving nerve block intervention got significantly lower VAS scores at 6 h, 24 h, and 48 h postoperatively (P < 0.05). However, there was no statistically significant difference in the incidence of adverse reactions between the two groups of patients (P > 0.05). Conclusion The application of the saphenous nerve plus selective tibial nerve block combined with general anesthesia in TKRS yields a promising analgesic effect, stable hemodynamics, low levels of postoperative inflammatory responses, and high safety.

Effectiveness of ERAS (Enhanced Recovery after Surgery) Protocol via Peripheral Nerve Block for Total Knee Arthroplasty.

Peripheral nerve block (PNB) for patients with total knee arthroplasty (TKA) is one of the recommended interventions in ERAS protocols. However, most existing studies involved unilateral TKA (UTKA). As such, this study aimed to evaluate the effectiveness of PNB in terms of immediate postoperative analgesia, length of hospital stays (LOS), and early functional outcomes in both UTKA and simultaneous bilateral TKAs (BTKAs). We reviewed 236 patients who underwent primary TKA with PNB, with 138 and 98 being UTKA and BTKAs, respectively; those in the PNB group underwent femoral nerve and adductor canal block. The matched control and PNB groups—who received intravenous/epidural patient-controlled analgesia (IVPCA/PCEA) alone or IVPCA in addition to PNB after surgery, respectively—were compared. The VAS scores at rest until 48 h after surgery were significantly lower in PNB groups compared to those in the IVPCA groups. At 0– 6 h of activity, VAS scores of the UTKA with PNB group were also lower than the IVPCA group. Compared to PCEA groups, VAS scores at 0–6 h of activity were higher in both the UTKA and BTKAs with PNB groups. However, at 24–48 h at rest, the scores of those in the UTKA with PNB group were lower than those in the PCEA group. The control and experimental UTKA and BTKAs groups had similar LOS and functional outcomes at 90 days postoperatively. In primary TKA, PNB has great analgesic effects for immediate postoperative pain control, and represents a similar analgesic effect to epidural PCA.

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

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

Minimum effective concentration of ropivacaine for ultrasound-guided adductor canal + IPACK block in total knee arthroplasty.

This study aimed to investigate the minimum effective concentration (MEC90, defined as effective in 90% of patients) of ropivacaine during the combined procedure of adductor canal block (ACB) and infiltration between the popliteal artery and capsule of the posterior knee (IPACK) block for patients undergoing total knee arthroplasty. This double-blind, randomized dose-finding trial was based on a biased coin up-and-down sequential design, where the concentration of ropivacaine administered to a given patient depended on the previous patient's response. Before surgery, the first patient received 20mL of 0.2% ropivacaine for ACB and again for IPACK. If the block failed, the next subject received a 0.025% higher ropivacaine concentration; otherwise, the next subject received either a 0.025% smaller dose (probability of 0.11) or the same dose (probability of 0.89). The primary outcome was whether the block was successful. Block success was defined as the patient did not suffer significant pain and did not receive rescue analgesia within 6 h after surgery. MEC90 was estimated by isotonic regression, and the 95% confidence interval (CI) was calculated by bootstrapping. Secondary outcomes were numerical rating scale (NRS) pain scores at postoperative 24 h and 48 h, postoperative morphine consumption, and time to hospital discharge. Secondary outcomes were compared between patients whose blocks succeeded with those which failed. Based on analysis of 52 patients, the MEC90 was 0.247% (95% CI 0.227-0.271%), MEC95 was 0.260% (95% CI 0.244-0.282%) and MEC99 was 0.272% (95% CI 0.260-0.291%). In contrast, four of nine trials in a recent systematic review reported ropivacaine concentrations below 0.247%. Patients whose blocks succeeded (n = 45) had significantly lower NRS pain scores, lower morphine consumption, and shorter hospitalization than patients whose blocks failed (n = 7). Our small trial suggests that 0.247% ropivacaine in 20mL respectively can provide successful ACB + IPACK block in 90% of patients. However, given that many published trials have used lower concentrations, our findings should be verified in larger studies.

Spacer-based gap balancing is useful in total knee arthroplasty: a 3-year follow-up of a retrospective study

BackgroundWhich technique, gap balancing or measured resection, can obtain better femoral component alignment and soft tissue balance in total knee arthroplasty (TKA) is still controversial. This study aimed to determine whether the gap balancing technique using a modified spacer block in TKA can result in better postoperative clinical outcomes than the measured resection technique.MethodsA total of 124 patients who underwent consecutive primary TKA between May 2016 and August 2018 were retrospectively reviewed. The gap balancing technique assisted by a modified spacer block was used in 61 patients, and the measured resection technique was used in 63 patients. The surgical, imaging and knee function outcomes of the two groups were compared.ResultsThe thickness of the posterior medial condyle bone resection using the modified spacer block tool in gap balancing was significantly larger than that of the MR technique (P = 0.001). Compared with the measured resection group, the gap balancing group had a greater external rotation resection angle of the femur (4.06 ± 1.10° vs. 3.19 ± 0.59°, P < 0.001°). Despite these differences, the mean ROM, KSS scores, and WOMAC scores at the 6-week, 1-year, and 2-year follow-ups were not significantly different. Postoperatively, there was no significant difference between the two groups in mechanical axis measurements (P = 0.275), the number of HKA outliers (P = 0.795) or the joint line displacement (P = 0.270).ConclusionThe functional outcomes of the gap balancing technique based on the modified spacer are similar to those of measured resection at 3 years. Compared with the MR technique, the GB technique resulted in a greater external rotation resection angle and thicker posterior medial condylar cuts in TKA with knee varus.

Anatomical Landmarks for Intraoperative Adductor Canal Block in Total Knee Arthroplasty: A Cadaveric Feasibility Assessment.

BackgroundPostoperative analgesia after knee arthroplasty forms a basis for an optimal range of motion after surgery. Femoral nerve blocks are established as a sensory nerve blockade but at the expense of quadriceps weakness delaying postoperative mobilization. The adductor canal block (ACB) similarly provides sensory blockade but preserves quadriceps function. If ACB is performed intraoperatively, it would reduce the time and cost needed for ACBs. This study aimed at investigating possible landmarks making it feasible to perform ACB intraoperatively.Material and methodsTwenty-seven knees were used. The superior pole of the patella, medial epicondyle, and adductor tubercle was proposed as landmarks to perform the ACB through a medial parapatellar approach. A needle was directed toward the adductor tubercle until a tactile feedback was felt. Ten to 15 mL India ink were injected using this technique. The adductor canal was dissected to visualize the ink spread and determine whether the saphenous nerve and the nerve to vastus medialis were exposed to the ink.ResultsThe anatomic landmarks were easily identified in all knees. The ACB resulted in the saphenous nerve and nerve to vastus medialis being bathed in ink consistently. A volumetric relationship was noted with the injectate. No injury to the neurovascular structures was observed.ConclusionsAn accurate and safe technique with reliable anatomic landmarks was presented to perform an ACB. In addition, an increase in injected ink volume correlated to an increase in the spread of ink; thus, we postulate that 10 mL of local anesthetic may be sufficient for an adequate regional block.

Is There an Optimal Timing of Adductor Canal Block for Total Knee Arthroplasty?-A Retrospective Cohort Study.

Adductor canal block (ACB) has gained popularity for postoperative pain control after total knee arthroplasty (TKA). However, its role in TKA has been questioned recently. Our study aimed to clarify the role of ACB in reducing postoperative pain after TKA and to elucidate an optimal timing to perform ACB for better outcomes. We conducted a comprehensive review of the perioperative records of 652 patients undergoing primary TKA from January 2019 to December 2019. Patients were divided into three groups: Group A received general anesthesia without ACB, Group B received ACB before inducing general anesthesia, and Group C received ACB at the post-anesthesia recovery unit (PACU). Patients in Groups B and C had lower pain visual analogue scale (VAS) scores than patients in Group A at the PACU. Opioid consumption was similar among the three groups; however, a slightly higher dose was required by Group A patients. Higher VAS scores were recorded in the ward in Group A than in Groups B and C with the leg at rest. In addition, higher VAS scores were recorded in Group A than in Groups B and C with the leg in continuous passive motion (CPM) training. More patients in Group A (34.9%) quit their first CPM training after a few cycles than those in Groups B (27.0%) and C (20.1%). Group A patients required a higher per kg dose of opioids in the ward than Groups B and C patients. Additionally, the hourly consumption of sevoflurane was similar among the three groups of patients, while Group A and C patients required a higher hourly per kg dose of intraoperative opioids than Group B patients. More patients in Group A (67.6%) and C (61.7%) developed intraoperative hypertension than patients in Group B (52.7%). There was no significant difference in PON (postoperative nausea), POV (postoperative vomiting), postoperative dizziness, or patient satisfaction among the three groups of patients. Group A patients had a longer length of hospital stay compared to Group B and C patients. In conclusion, preoperative ACB could be a better choice for patients undergoing TKA as it decreases intraoperative opioid consumption and facilitates a stable hemodynamic state during surgery.