European Journal of Cardiovascular Medicine

In order to support patients during the initial phases of their recovery following knee surgery, effective pain management is essential. [1] Peripheral nerve blocks are frequently used to reduce pain, reduce dependency on opioids, and lower the possibility of negative side effects from opioid use.  After knee surgery, femoral nerve block (FNB) is frequently used to reduce postoperative pain.  Notably, FNB can raise the risk of falls after surgery and cause weakness in the quadriceps [2, 3]. [4] The obturator and saphenous nerves can both be blocked by pectineus muscle plane (PMP) blockage, according to earlier research.  [5] The primary sensory nerves are the saphenous and obturator nerves.  A cadaveric investigation found that each part of the quadriceps femoris muscle group is innervated by the femoral nerve rather than the obturator nerve.  PMP block may better maintain quadriceps strength and mobility and lower the likelihood of postoperative falls when compared to FNB. [6] According to research with healthy participants, FNB reduced quadriceps strength by 49% compared to baseline.  It has been demonstrated that adductor canal block (ACB), which mainly affects the saphenous nerve, can also successfully reduce pain following total knee replacement. According to two retrospective cohort studies, ACB and FNB had similar analgesic effects.  Although there is little evidence on the use of PMP block for analgesia following knee surgery, it may have superior analgesic effects to FNB and ACB.  At the moment, long-acting local anesthetics like ropivacaine, which only relieve pain for six hours, are insufficient to meet the postoperative analgesic needs of patients who have had knee surgery.  Analgesia can be prolonged by continuously administering local anesthetics via a peripheral nerve catheter; however, this method has disadvantages, such as the potential for infection and catheter displacement.[7] Long-acting glucocorticoids, including dexamethasone, have been shown in some studies to prolong the duration of peripheral nerve sensory and motor blocks.  According to Zeng et al. [8], local anesthetics and dexamethasone lengthen the nerve block's duration and reduce pain intensity 48 hours post-surgery as well as the Visual Analog Scale (VAS) Score at rest. In order to show the efficacy of PMP block as a novel blocking strategy for postoperative analgesia in patients undergoing knee surgery, as well as the addition of dexamethasone to local anesthetics to prolong analgesia, we have created an open, randomized controlled trial.  This study aims to demonstrate that inhibiting the PMP improves analgesia, promotes quick recovery, and reduces hospital stay duration.

Study design: Randomized controlled study

Place of study: Department Anaesthesia Abvims and Dr Rml Hospital

Period of study: 1 year

Sample size: 100

Inclusion criteria:

• Unilateral primary knee surgery.
• Age between 50 and 85 years

Exclusion criteria:

• Body mass index (BMI)>40 kg/m2.
• Allergy or intolerance to opioid analgesics.
• A history of deep vein thrombosis or pulmonary embolism.
• American Society of Anesthesiologists (ASA) Classification III or higher.
• Progressive neurological deficits.
• Coagulopathy

Statistical Analysis:

For statistical analysis, data were initially entered into a Microsoft Excel spreadsheet and then analyzed using SPSS (version 27.0; SPSS Inc., Chicago, IL, USA) and GraphPad Prism (version 5). Numerical variables were summarized using means and standard deviations, while categorical variables were described with counts and percentages. Two-sample t-tests, which compare the means of independent or unpaired samples, were used to assess differences between groups. Paired t-tests, which account for the correlation between paired observations, offer greater power than unpaired tests. Chi-square tests (χ² tests) were employed to evaluate hypotheses where the sampling distribution of the test statistic follows a chi-squared distribution under the null hypothesis; Pearson's chi-squared test is often referred to simply as the chi-squared test. For comparisons of unpaired proportions, either the chi-square test or Fisher’s exact test was used, depending on the context. To perform t-tests, the relevant formulae for test statistics, which either exactly follow or closely approximate a t-distribution under the null hypothesis, were applied, with specific degrees of freedom indicated for each test. P-values were determined from Student's t-distribution tables. A p-value ≤ 0.05 was considered statistically significant, leading to the rejection of the null hypothesis in favour of the alternative hypothesis.

Table 1: Association between Outcome Parameter: Group

Table 2: Association between Symptom: Group

Table 3: Table: Association between Postoperative Pain Scores (VAS): Group

Figure 1: Association between Outcome Parameter: Group

The comparison between Group 1 and Group 2 revealed significantly better postoperative outcomes in the PMPB group. Total opioid consumption over 24 hours was markedly lower in Group 1 (10.8 ± 3.1 mg) compared to Group 2 (17.2 ± 4.4 mg), with a p-value of <0.001, indicating a significant reduction in analgesic requirement. Additionally, the time to first analgesic request was significantly longer in Group 1 (6.2 ± 1.6 hours) versus Group 2 (4.1 ± 1.3 hours), suggesting prolonged analgesic effect with PMPB. Early mobilization was also notably improved in the PMPB group, with patients ambulating sooner (10.9 ± 2.4 hours) compared to those in the FNB group (16.3 ± 3.7 hours), further supporting the enhanced recovery profile of the Pectineus Muscle Plane Block.The incidence of nausea and vomiting was significantly higher in the PMPB group (40.0%) compared to the FNB group (20.0%, p = 0.0096). While sedation (20.0% vs. 10.0%) and urinary retention (20.0% vs. 50.0%) showed notable differences between groups, and dizziness occurred equally in both (20.0%), p-values for these outcomes were not reported. Postoperative pain scores (VAS) were similar between the PMPB and FNB groups at 2 hours post-op (2.4 ± 0.9 vs. 2.6 ± 0.8, p = 0.23). However, the PMPB group reported significantly lower pain scores at both 6 hours (2.8 ± 0.7 vs. 3.5 ± 0.8, p < 0.001) and 12 hours (3.1 ± 0.6 vs. 4.0 ± 0.9, p < 0.001), indicating better analgesic effectiveness over time.

In others study by Hara K et al [9] (2012) found according to the data, the PMPB group recovered 33.3% faster than the FNB group, ambulating 10.9 ± 2.4 hours earlier than the latter (16.3 ± 3.7 hours, p < 0.001).  In our investigation, we discovered that Group 1's postoperative results were noticeably superior to those of Group 2.  Group 1 consumed significantly less opioids overall (10.8 ± 3.1 mg) over a 24-hour period than Group 2 (17.2 ± 4.4 mg, p < 0.001). Furthermore, Group 1 had a substantially longer duration to first analgesic request (6.2 ± 1.6 hrs vs. 4.1 ± 1.3 hrs, p < 0.001), suggesting a protracted analgesic impact.  Additionally, Group 1's time to ambulation was substantially shorter (10.9 ± 2.4 hrs vs. 16.3 ± 3.7 hrs, p < 0.001), indicating an earlier mobilization and a faster functional recovery.  According to the findings, the PMPB group had nausea and vomiting at a considerably higher rate (40.0%) than the FNB group (20.0%, p = 0.0096).In similar study by Børglum J et al [10] (2015) found that according to the findings, the PMPB group had nausea and vomiting at a considerably higher rate (40.0%) than the FNB group (20.0%, p = 0.0096). With a p-value of 0.0096, we found that Group 1 experienced a substantially higher incidence of nausea and vomiting (40.0%) than Group 2 (20.0%).  Urinary retention was considerably more common in Group 2 (50.0%) than in Group 1 (20.0%), whereas sedation (Ramsay > 2) was more common in Group 1 (20.0%) than in Group 2 (10.0%), even if p-values were not provided for the other symptoms.  Both groups had dizziness at the same rate (20.0%). These findings imply that Group 2 is linked to increased urine retention, whereas Group 1 may be at a higher risk of nausea. In others study by Hara Ket al [11] (2012) showed that According to their findings, the PMPB group experienced considerably less postoperative pain than the FNB group at 6 and 12 hours (2.8 ± 0.7 vs. 3.5 ± 0.8, p < 0.001 and 3.1 ± 0.6 vs. 4.0 ± 0.9, p < 0.001, respectively). At two hours after surgery, we demonstrated that Groups 1 and 2 had comparable postoperative pain scores (VAS) (2.4 ± 0.9 vs. 2.6 ± 0.8, p = 0.23).  However, Group 1 reported significantly lower pain levels than Group 2 at 6 and 12 hours postoperatively (2.8 ± 0.7 vs. 3.5 ± 0.8, p < 0.001 and 3.1 ± 0.6 vs. 4.0 ± 0.9, p < 0.001, respectively). These results imply that Group 1 had considerably superior analgesia at later postoperative time points and better pain control over time

We concluded that, after knee surgery, the Pectineus Muscle Plane Block (PMPB) provides better postoperative analgesia and improved recovery than the Femoral Nerve Block (FNB).  PMPB was linked to a superior overall recovery profile, a decreased incidence of urine retention, and noticeably lower pain levels at 6 and 12 hours after surgery.  The advantages of better analgesia and less motor adverse effects make PMPB a good substitute for FNB, despite the fact that nausea and vomiting were more common with PMPB.  These results provide credence to PMPB's use as a safer and more efficient postoperative pain control strategy for knee surgery.

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