Ultrasound Guided Adductor Canal Block vs Intra Articular Analgesia for Post-operative Pain Relief after Arthroscopic Knee Surgeries: A Comparative Evaluation.

CONTEXT AND AIMS: Our aim was to assess the postoperative analgesia after ultrasound-guided "Adductor canal block" (ACB) and "Intraarticular Analgesia" (IAA) in arthroscopic knee surgeries postoperatively. SETTINGS AND
DESIGN: This experimental, randomized prospective study was conducted in the Department of Anesthesia, Himalayan Institute of Medical Sciences, Dehradun. SUBJECTS AND METHODS: Sixty patients, who underwent arthroscopic knee surgeries were divided into two groups, with 30 patients each. Each group was given spinal anesthesia using 3 ml of 0.5% hyperbaric Bupivacaine. After completion of surgery, Group I patients were given ultrasound-guided ACB, Group II patients were given IAA. Postoperatively, pain was assessed using the Numeric Rating Scale (NRS). Time of first analgesic requirement and total postoperative tramadol consumption in the 1st 24 h were recorded.
RESULTS: No significant difference was seen between both groups pertaining to patient's demographic data, type, and duration of surgery. The difference in the median NRS score between both the groups at different time intervals was statistically insignificant (P > 0.05). Total tramadol consumption in Group I (172.85 ± 82.59) mg was more than Group II (157.85 ± 33.83) mg. The duration of first analgesic requirement was 351.43 min, 342.86 min for Group I and II, respectively.
CONCLUSION: To conclude, both ACB and IAA provide good postoperative pain control in arthroscopic knee surgeries with no significant difference in pain scores and postoperative analgesic requirement. Copyright:

INTRODUCTION

Utilization of ultrasound has led to increase in the number of newly described musculofascial plane blocks because of real-time visualization of nerves, needle, and other anatomical structures.[12]

Adductor canal or Hunter's canal is a pyramidal-shaped, aponeurotic tunnel present on the medial and middle 1/3rd part of the thigh. The Saphenous nerve, branch of femoral nerve which supplies the anteromedial, posteromedial, and medial parts of the lower limbs from distal thigh to medial malleolus.[3] Adductor canal block (ACB) includes injecting a local anesthetic (LA) directly into the adductor canal, deep to the Sartorius muscle. The LA then spreads throughout the canal of adductor with involvement of saphenous nerve, thus resulting in sensory analgesia of its dermatomal distribution without any appreciable motor block. The saphenous nerve is primarily a sensory nerve.[4] “Intra-articular analgesia” (IAA) has also shown to be effective in pain control and duration and quality of analgesia. It is delivered to patients by injection of either LA, opioids, steroids, or a combination of above directly in the knee joint, after the completion of the surgery.

The arthroscopic anterior cruciate ligament (ACL) reconstruction surgery is a common orthopedic procedure. Patients after arthroscopic ACL reconstruction suffer from moderate to severe degree pain in the postoperative period. There are various modalities for postoperative pain management after arthroscopic ACL reconstruction surgeries such as systemic analgesics (non-opioids and opioids), intra-articular analgesics, neuraxial blocks, and peripheral nerve blockade. ACB is among the most efficient pain management modality in this context.[5] Evidences reinstate multimodal analgesia as a better approach for postoperative pain. It decreases opioid requirement and at the same time reduces opioid related side effects.[6] Peripheral nerve blocks alone or when given as a part of multimodal analgesia are one of the safest and most effective methods for postoperative pain control. It causes decreased length of hospital stay, faster recovery, and prevents readmissions.[7]

In this study, our aim was to assess the postoperative analgesia after ultrasound-guided ACB and IAA in arthroscopic knee surgeries postoperatively.

SUBJECTS AND METHODS

This randomized controlled, prospective study was performed at a tertiary care health center (Himalayan Institute of Medical sciences, Dehradun) for a period of 12 months after the Institutional Ethics Committee approval (SRHU/HIMS/ETHICS/2020/59). Informed consent in written was taken from the patients listed undergoing elective arthroscopic knee surgery. Seventy-six patients of either sex, 18–65 years of age, “American Society of Anesthesiology” (ASA) classes I and II were recruited in the study.

Patient refusing for regional anesthesia, allergy to local anesthetics, bleeding disorders, local site infection, patient on anti-coagulants, inability to give informed consent, severe liver and kidney disease, patients with inability to operate patient controlled analgesia (PCA) system and psychiatric disorders were excluded from the study. Out of 76 patients, 16 patients were excluded from the study [Figure 1].

Figure 1

Consort diagram

Eligible patients were kept fasting for 6 h for solid food and 2 h for clear fluid prior to surgery. Patients were given tablet ranitidine 150 mg and tablet alprazolam 0.25 mg HS and 2 h prior to surgery as a premedication.

In preoperative room, all the patients were explained about the anesthetic procedure and the interpretation of Numeric Rating Scale (NRS). In the operating room after establishing intravenous (i.v.) access, standard monitoring such as noninvasive blood pressure, Electrocardiography, and SpO2 were recorded.

The patients were assigned to receive either ACB or IAA. Thirty patients were allocated to each group. After enrolment, group assignments were determined by a computer-generated number sequence and were contained in sequentially numbered opaque envelopes to ensure blinding.

The anesthetic technique for all patients was spinal anesthesia. Spinal anesthesia was given in the sitting position at L3–4 or L4–5 inter-vertebral level in median approach with 25-gauge spinal needle and 3 ml of 0.5% bupivacaine (hyperbaric) was injected intrathecally. The patient was then positioned supine immediately. After adequate anesthesia effect, surgical procedure was started. Ultrasound-guided ACB (Group A) or IAA (Group B) was performed after the completion of surgery and was performed by trained anesthesiologist with experience in ultrasound imaging for nerve blocks for >1 year. Ultrasound machine used was (M TURBO. FUJIFILM Sonosite, Inc. 21919 Bothell, WA 98021 USA). US probe used was Linear 6–13 MHz.

ACB was performed in the supine position with the extremity was slightly abducted and rotated externally where the block was to be administered. Ultrasound probe was kept in transverse cross-sectional view, midway in between anterior superior iliac spine, up to the patella, at mid-thigh level. Identification of femoral artery was done beneath the muscle sartorius, the femoral vein being inferior to the femoral artery, and saphenous nerve lying just lateral to the femoral artery was traced as the target injection site. A needle of 22 G and 100 mm was introduced in-plane lateral to medial and 9 ml of 0.2% Ropivacaine and 1 ml of 150 mcg Clonidine was injected.

In another group of patients, at the end of the surgical procedure, just before closure of skin, the IAA cocktail was prepared by an anesthesiologist composed of 9 ml of 0.2% ropivacaine and 1 ml of 150 mcg clonidine, and administered via the port site in the intraarticular space by the surgeon.

Patients were transferred to postanesthesia care unit. Monitoring and recording of standard parameters such as BP (systolic/diastolic/mean), heart rate, and oxygen saturation (SpO2) was done. The intensity of pain was assessed by using NRS scoring system from 20 min after the block followed by assessment at 1, 3, 6, 12, 18, and 24 h. Injection Dynapar (diclofenac sodium) 75 mg i.v. was given twice daily as an anti-inflammatory agent. Tramadol (PCA) pump was used as an analgesic supplement for rescue analgesia so that patient can themselves administer tramadol, if required. The demand dose of tramadol through PCA pump was 20 mg with lockout interval of 10 min. The time duration of the first analgesic demanded by the patient and the total amount of tramadol consumed after 24 h of surgery were recorded.

In the statistical analysis, the primary outcome was NRS score. NRS is a 10-point scale with 10 denotes “worst pain imaginable” and 0 indicates “no pain.” Higher the scores, worse are the outcomes.

The secondary outcome variables were as follows:

Total opioid consumption over 24 h

Time of first analgesic used over 24 h (time from block administration to first analgesic demand by the patient)

Any opioid-related side effects during first 24 h

Likert-scale questionnaire on POD 1 was done to know the patient's satisfaction.

Statistical analysis

The Statistical Package for the Social Sciences System software version SPSS 22 was used for statistical testing. For unevenly distributed data, mean ± standard deviation or median was used to denote the continuous variables. Percentages and frequencies represented the categorical variables. Continuous variables are compared between the groups using the Student's t-test. Chi-squared test, or Fisher's exact test were used to compare nominal categorical data between the groups. The Mann Whitney U-test was used to compare the nonnormal distribution variables. For all statistical tests, a P < 0.05 is considered to indicate a significant difference.

RESULTS

A total of 76 patients fulfilling the eligibility criteria were included in the study, of which 60 completed the study. Table 1 shows that patient's demographics, ASA class, type of the surgeries, subarachnoid block duration, and duration of surgery were statistically similar.

Table 1

Demographic characteristics, American society of Anesthesiology status and surgical duration comparison

Variables	Group A (n=30)	Group B (n=30)	P
Age (years), mean±SD	31.90±9.61	38.17±11.34	0.025
Sex male:female	21:9	17:13	0.056
ASA I:II	26:4	23:7	0.317
Duration of subarachnoid block	217.00±24.65	215.33±18.75	0.769
Duration of surgery (min), mean±SD	91.00±20.14	91.33±21.25	0.950

ASA=American society of Anesthesiology, SD=Standard deviation

Table 2 shows postoperative comparison of NRS score in 60 patients at different time interval in both the groups. Data are represented as median and interquartile range. The difference in the median NRS score between both the groups at different time intervals was statistically not significant (P > 0.05) [Figure 2 and Table 2].

Table 2

Comparison of Numeric Rating Scale

	Group A (n=30), median (IQR)	Group B (n=30), median (IQR)	P
NRS 20 (min)	0.00 (0-0)	0.00 (0-0)	-
NRS 1 (h)	0.00 (0-0)	0.00 (0-0)	-
NRS 3 (h)	0.00 (0-0)	0.00 (0-0)	-
NRS 6 (h)	2.00 (0.75-3.0)	2.00 (1.75-3.00)	0.432
NRS 9 (h)	2.50 (2-4)	2.00 (2-3.25)	0.800
NRS 12 (h)	2.00 (1-3.25)	2.00 (1-3)	0.887
NRS 18 (h)	1.00 (0.75-2.25)	2.00 (1-3)	0.731
NRS 24 (h)	1.00 (0-2.0)	1.00 (1-2)	0.217

*Data represented outside bracket is the median, and the one inside the bracket in interquartile range. P value of first 3 reading was not calculated, as the score was 0. IQR=Interquartile range, NRS=Numeric Rating Scale[14]

Figure 2

Comparsion of Numeric Rating Scale score among study groups

Table 3 shows postoperative consumption of total dose of tramadol in 60 patients of both the groups. The mean of total tramadol consumption in Group A patients was 172.85 ± 82.59 mg, whereas in Group B, patients were 157.85 ± 70.20 mg. Two patients from each group did not require any tramadol in the postoperative period. All the patients were similar with regard to total dose of tramadol consumption with no statistical difference (P = 0.46) [Figure 3 and Table 3].

Table 3

Postoperative consumption of tramadol

	Group A	Group B	P
Total tramadol consumption (mg) (n=28)	172.85±82.59	157.85±33.83	0.46

Figure 3

Consumption of tramadol in patients

Table 4 shows postoperative requirement of first analgesics in 60 patients of both the groups. The mean time for requirement of first analgesic in minutes was 351.43 ± 92.62 in Group A while 342.86 ± 97.85 in Group B. All the patients were similar with regard to time of requirement of first analgesic with no statistical difference (P = 0.738) [Table 4].

Table 4

Postoperative requirement of analgesia

	Mean±SD		P
	Group A	Group B
Times of first analgesic	351.43±92.655	342.86±97.851	0.738

SD=Standard deviation

No statistically significant difference was found for opioid-related side effects among both the groups (P value-0.72).

Patient's satisfaction was assessed next day after 24 h of the study using the Likert scale. Table 5 shows that 11 patients of Group A were strongly agree of overall pain management, whereas in Group B, only eight patients were strongly agree to overall pain management. The difference in the overall pain management between both the groups was statistically not significant (P > 0.749).

Table 5

Likert Scale

Overall pain management	Group A, n (%)	Group B, n (%)	P
Disagree	1 (3.3)	0	0.749
Slightly disagree	4 (13.3)	5 (16.7)
Slightly agree	6 (20.0)	8 (26.7)
Agree	8 (26.7)	9 (30.0)
Strongly agree	11 (36.7)	8 (26.7)
Total (n)	30 (100.0)	30 (100.0)

DISCUSSION

In the present study, we have compared the efficacy of analgesics via USG (ultrasound) guided ACB and IAA with ropivacaine and clonidine following arthroscopic knee surgery under sabarachnoid block. We found that the analgesic efficacy provided by ACB is same as provided by intrarticular analgesia, similarly a latest study conducted by Kampitak et al. found pain control which was better postoperatively after ACB was administered, with lower dose opioids consumption when compared with periarticular infiltration in unilateral total knee arthroplasty (TKA) patients. This may be due to the difference between the two different techniques for periarticular infiltration in both the studies. In their study, Kampital et al. injected cocktail in the area surrounding fat, prosthesis and subcutaneous tissues, but contrary to the study of ours, we injected the drug in the knee joint i: e intraarticular. They used 60 ml of drug volume in all the patients, but in our study, we used only 10 ml of drug. In the above study, they administered drugs levobupivacaine, drug adrenaline, NS and morphine, but we used a mixture of ropivacaine and clonidine for local and tramadol for PCA pump.[8] In a study conducted by Kevin Stebler et al., they also compared the USG-guided ACB versus local infiltration analgesia in reconstruction of ACL surgeries for postoperative analgesia in the patients operated under general anesthesia. For each intervention, they gave a 20 ml of 0.5% ropivacaine with i.v. patient controlled morphine and they concluded that total 24 h i.v. morphine usage was similar in both the groups (group ACB 17.1 mg and LIA group 17.7 mg) and similarly no differences between the two groups were seen in the postoperative pain score. They also took a numerical rating score to assess postoperative pain score. In our study total consumption of tramadol was lower in intra-articular group (157.85 mg) as compared to ACB group (172.85 mg) but is also statistically insignificant. Our study concluded that there was no significant difference in total 24 h i.v. tramadol consumption administered through PCA pump between both the groups. Hence, our results are comparable to the study done by Kevin Stebler. We used similar volume of heavy bupivacaine for subarachnoid block in both the groups, and it was noted that the effect does not last more than 2–2.5 h postsurgery and multimodal analgesia protocol postoperatively, in patients of both the groups was also the same. Hence, the factors mentioned above have minimal or no conflicts in the study.[9]

We used tramadol in PCA pump instead of morphine as tramadol has pain relief similar to morphine with the added benefit that it does not cause abuse potential, tolerance or addiction.[10]

In our study, we noted the time for first rescue analgesia, duration of postprocedural analgesia duration, and requirement of drug tramadol in both groups. The time duration where the first requirement of analgesia after surgery through PCA pump was 351.43 min. in Group A patients and 342.86 min. in Group B patients and between two groups no differences that were significant, was observed. Kampitak et al. in their study compared a single shot ACB with or without LIA to reduce postsurgical pain after TKA and found that both modalities of pain control are comparable. Our results are in accordance with their study. They also found that there was significant benefit of combining the LIA with a single shot ACB which delayed the time duration for first rescue analgesia request. The explanation for the above finding might be due to both modalities of multimodal analgesia used thus covering saphenous nerve block at adductor canal as well as entire area for the local tissue around the operative site that could contribute for better analgesia. However the effect of combining both modality was only up to 6–8 h. The disadvantages of combining both technique are time-consuming and technically demanding and require more practice to develop consistent skills.[11] In our study, after 24 h, we assessed the patients of both the group for overall pain management in the form of Likert scale, but there was no significant difference observed. Zhao et al. conducted a meta-analysis, and comparison was done between ACB and local infiltration analgesia. Total eight root canal treatments with 675 patients concluded that no statistically significant difference was seen in the scores of pain and total consumption of opioids at 24 h or 48 h after the surgical procedure between both groups.12 A study by Sawhney et al. and Li et al. used NRS for assessment of pain, rest all studies in the trial, used VAS for pain assessment. According to the pooled data, it is clear that the ACB group and the LIA had similar scores of pain at 24 and 48 h regardless the patient who was at rest or mobile. We assessed the pain only up to the 24 h at rest and the NRS score was used for pain assessment. Similar to our study, Gwam et al. also conducted a retrospective cohort study and concluded that there was no statistically significant difference seen in total opioid consumption and VAS score between both the groups.[13]

Hence, we finally conclude that “alleviating postsurgical pain is one of the main challenges in modern era as it also leads to early rehabilitation and improved patient outcome. IAA and ACB are both cost-effective and excellent modalities in this regard.” We found out that they are comparably effective in controlling postoperative pain after knee arthroscopic surgeries.

CONCLUSION

No significant difference was seen in pain scores for initial 24 h so both the techniques are equally effective and also no significant difference was seen in rescue analgesic requirement postoperatively, in both modalities of pain management in knee arthroscopic surgeries.14

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.