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Background:Periarticular local infiltration analgesia (LIA) is largely utilized for controlling pain after total knee arthroplasty (TKA). The present work aimed to assess the efficacy of a modified LIA cocktail for patients undergoing TKA.Methods:Magnesium sulfate (MgSO4) and sodium bicarbonate (NaHCO3) were added to a conventional LIA cocktail comprising ropivacaine, epinephrine, and dexamethasone. After the safety of this modified cocktail was tested in rats, its efficacy and safety were evaluated in a prospective, double-blinded study including 100 individuals randomized to receive periarticular infiltration of the modified cocktail or a conventional cocktail. The primary outcome was postsurgical use of morphine hydrochloride for rescue analgesia. Secondary outcomes were the time until the first rescue analgesia, postsurgical pain (on a visual analog scale [VAS]), functional recovery (assessed by range of knee motion and ambulation distance), time to discharge, and complication rates.Results:Adding NaHCO3 to the local anesthetics caused some instantaneous precipitation in all cases. Administering the modified cocktail to rats did not obviously damage the injected area of the nerve or surrounding tissues. Administration of the modified cocktail to patients was associated with markedly reduced postsurgical morphine use in the initial 24 hours (4.2 ± 5.0 versus 14.6 ± 8.9 mg, p < 0.001), reduced total morphine use (9.8 ± 8.4 versus 19.6 ± 11.4 mg, p < 0.001), prolonged time to the first rescue analgesia, lower VAS pain scores at rest and during motion at 12 and 24 hours following the operation, better functional recovery on postoperative days 1 and 2, and a shorter hospital stay. The modified and conventional cocktail groups had similar rates of complications.Conclusions:The present modification of a conventional cocktail significantly prolonged analgesia and reduced opioid consumption, which may substantially improve pain control in arthroplasty.Level of Evidence:Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

ObjectivePreemptive 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.MethodsThis 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.ResultsThe 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.ConclusionsIn 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.

Introduction This study aimed to compare the analgesic efficacy of different concentrations of ropivacaine used for the combination of ultrasound-guided adductor canal block (ACB) and infiltration between the popliteal artery and capsule of the posterior knee (IPACK) block in total knee arthroplasty (TKA). Materials and Methods Before general anesthesia, 90 patients undergoing TKA were randomized to receive ACB + IPACK block with ropivacaine 0.2, 0.25, or 0.3% (defined as group A, B, and C, respectively). Primary outcome was the reported visual analog scale (VAS) pain scores at rest 30 minutes following arrival to the postanesthesia care unit (PACU). Secondary outcomes were postoperative VAS pain scores, postoperative morphine consumption, the time to first rescue analgesia, functional recovery of knee (including the range of motion and quadriceps strength), and postoperative complications. Results Compared with group A, group B and group C had significantly lower VAS scores 30 minutes following arrival to the PACU (p < 0.001 and p < 0.001, respectively). These two groups also had significantly lower VAS pain scores at postoperative 2 hours (at rest: p = 0.037 and 0.002; during motion: p = 0.035 and 0.001, respectively) and 6 hour (at rest: p = 0.033 and 0.002; during motion: p < 0.001 and p < 0.001, respectively), lower postoperative morphine consumption (p = 0.001 and 0.002, respectively), longer time to first rescue analgesia (p = 0.010 and 0.009, respectively), and better range of knee motion on the day of surgery (p = 0.008 and 0.002, respectively). Group B and group C showed no significant differences in these outcomes between each other (p > 0.05). The three groups did not show a significant difference in postoperative quadriceps strength and complication rates (p > 0.05). Conclusion Compared with ropivacaine 0.2%, ropivacaine 0.25 and 0.3% can provide early pain relief in the first 6 hours after surgery. Ropivacaine 0.25 and 0.3% may provide more clinical benefits for patients undergoing outpatient TKA.

BackgroundPreemptive multimodal analgesia is a commonly used method to control pain following total knee arthroplasty (TKA). This study aimed to evaluate the efficacy of preemptive acetaminophen for pain management in patients who underwent TKA.MethodsIn this prospective, double-blind, randomized placebo-controlled trial, 80 patients were randomized to the acetaminophen or control group. Patients in the acetaminophen group received celecoxib 400mg, pregabalin 150mg, and acetaminophen 325mg 2 hours before TKA. Patients in the control group received celecoxib, pregabalin, and placebo. Primary outcome was postoperative consumption of morphine hydrochloride used for rescue analgesia. Secondary outcomes included the time to the first rescue analgesia, postoperative pain as assessed by visual analogue scale (VAS), functional recovery as assessed by range of knee motion and ambulation distance, the time to hospital discharge, and complication rates.ResultsThere was no significant difference between the control group and the acetaminophen group in postoperative 0–24 h morphine consumption (average 11.3 mg vs. 12.3 mg, p = 0.445) and total morphine consumption (average 17.3 mg vs. 19.3 mg, p = 0.242). There was no significant difference in the time to the first rescue analgesia, postoperative VAS pain scores at any time points, postoperative functional recovery of knee, and the time to hospital discharge. The two groups had a similar occurrence of postoperative complications.ConclusionsThe addition of acetaminophen to preoperative preemptive multimodal analgesia could not reduce postoperative morphine consumption or improve pain relief. Orthopedic surgeons should reconsider routine use of preemptive acetaminophen in TKA.Trial registration: The study was prospectively registered on Chinese Clinical Trial Registry (identification number: ChiCTR2100052732) on 04/11/2021. http://www.chictr.org.cn/edit.aspx?pid=136730&htm=4