|Year : 2016 | Volume
| Issue : 2 | Page : 96-100
Efficacy of intra-articular dexmedetomidine for postoperative analgesia in arthroscopic knee surgery done under spinal anesthesia
Khawer Muneer, Hina Khurshid, Javid Iqbal Naqashbandi
Department of Anaesthesiology, Government Medical College, Srinagar, Jammu and Kashmir, India
|Date of Web Publication||18-Jul-2016|
Department of Anaesthesiology, Government Medical College, Srinagar, Jammu and Kashmir
Source of Support: None, Conflict of Interest: None
Background: Postoperative pain is a common and distressing symptom after knee arthroscopy. This study aims at analyzing the efficacy of intra-articular dexmedetomidine for postoperative pain relief in patients undergoing arthroscopic knee procedures under unilateral spinal anesthesia. Materials and Methods: Fifty adult patients of American Society of Anaesthesiologists Class 1-2, aged 20-60 years posted for arthroscopic knee surgery were randomly divided into Groups I (control group) and II (dexmedetomidine group) with 25 patients in each group. Anesthetic technique used was unilateral spinal in all the patients. Group I was the control group and Group II the dexmedetomidine group. Group II patients received 1 μg/kg dexmedetomidine diluted to 20 ml in normal saline via intra-articular route at the end of the procedure and Group I patients received an equal volume of normal saline. Visual analog scale (VAS) score for 24 h, time to give the first dose of analgesia and total dose of analgesic required in each group was evaluated. Results: VAS scores were significantly lower in Group II, time to first analgesic requirement was significantly greater in Group II (308 ± 3.59) than in Group I (244 ± 2.92), P < 0.001 and total dose of analgesic used in Group II (36 mg ± 7.65) patients was significantly lesser compared to patients in Group I (129 mg ± 6.87), P < 0.001. Conclusion: Intra-articular dexmedetomidine is effective in providing prolonged postoperative analgesia after arthroscopic knee procedures and reduces the total dose of analgesic required postoperatively.
Keywords: Analgesia, dexmedetomodine, intra-articular, knee arthroscopy
|How to cite this article:|
Muneer K, Khurshid H, Naqashbandi JI. Efficacy of intra-articular dexmedetomidine for postoperative analgesia in arthroscopic knee surgery done under spinal anesthesia. Indian J Pain 2016;30:96-100
|How to cite this URL:|
Muneer K, Khurshid H, Naqashbandi JI. Efficacy of intra-articular dexmedetomidine for postoperative analgesia in arthroscopic knee surgery done under spinal anesthesia. Indian J Pain [serial online] 2016 [cited 2019 May 25];30:96-100. Available from: http://www.indianjpain.org/text.asp?2016/30/2/96/186464
| Introduction|| |
Arthroscopic knee surgery is performed as an outpatient procedure using a variety of anesthetic techniques.  This procedure is minimally invasive and involves repair of ligaments and menisci, and additional analgesia is required to provide pain relief due to substantial pain complained by the patients postoperatively.  This can be particularly challenging for the anesthesiologist who must decide on the appropriateness of the patient and procedure for outpatient surgery and an anesthetic that is adequate for the procedure, but provides the patient's expectation of an uncomplicated postoperative recovery with minimal pain.  General anesthesia is a safe and effective anesthetic for arthroscopic surgery, but it has been associated with increased postoperative nausea, vomiting, and pain. , Regional anesthesia can be a good alternative as it obviates these complications of general anesthesia.  Unilateral spinal anesthesia for knee arthroscopic procedures can be advantageous as it minimizes cardiovascular effects, avoids motor block of nonoperative limb, and facilitates early discharge. ,
Arthroscopic knee surgeries can evoke variable levels of pain, which at times is very distressing for patients. , Postoperative pain can prevent early mobilization, discharge, and rehabilitation.  Different analgesic agents for day care arthroscopy have been studied but an ideal agent needs to be identified. It should be active upon cessation of surgery, have a prolonged duration of action, be easy to administer and be without serious adverse effects.  Dexmedetomidine is a potent and highly selective alpha 2 adrenergic agonist with sedative, anxiolytic, analgesic, and sympatholytic effects.  It has been used intravenously and has been shown to provide some analgesic effect after arthroscopic knee surgery but there were some adverse hemodyanamic effects such as hypotension and bradycardia.  Intra-articular administration of dexmedetomidine may be useful to avoid the adverse effects while still providing postoperative analgesia. 
The aim of our study was to analyze the efficacy of intra-articular dexmedetomidine in providing prolonged pain relief in patients undergoing arthroscopic knee surgery under unilateral spinal anesthesia.
| Materials and Methods|| |
This study was conducted in the Department of Anaesthesiology in collaboration with the Department of Orthopaedics. Approval was obtained from the ethics committee of the institution and written informed consent was obtained from the patients.
Fifty patients of either sex between the age group of 20-60 years belonging to American Society of Anaesthesiologists (ASA) Class 1 and 2 undergoing elective arthroscopic knee surgery were included in the study. Type of anesthetic technique was unilateral spinal anesthesia using 1.5 ml of 0.5% hyperbaric bupivacaine.  The patients were divided into two Groups I and II with 25 patients in each group. Group I was the control group and Group II the dexmedetomidine group. Group II received intra-articular dexmedetomidine 1 μg/kg diluted to 20 ml; at the end of procedure and Group I received an equal volume of normal saline.
Following patients were excluded from the study: Impaired renal and hepatic function, history of heart disease, uncontrolled hypertension, opioid or nonsteroidal anti-inflammatory drug use 24 h before surgery, cases in which drain insertion was required postoperatively.
In the operating room, multichannel monitor was attached, and baseline noninvasive blood pressure, electrocardiogram, heart rate, and arterial oxygen saturation was noted in all the patients. Visual analog scale (VAS) was explained to all patients preoperatively (0 - no pain and 10 - worst pain imaginable). Intravenous line was secured in all the patients. Patients were positioned in lateral decubitus position with the limb to be operated in dependent position. Using aseptic precautions lumbar puncture was established with a midline approach at L3-L4 interspace using 26G Quincke spinal needle, and 1.5 ml of 0.5% bupivacaine (hyperbaric) was injected slowly keeping the needle orifice toward the dependent side. The lateral decubitus position was maintained for 15 min before starting the procedure. The adequacy of spinal anesthesia was assessed and confirmed when sensory block was upto T 12 level and motor block >2 score with modified Bromage scale (0 - no block, 1-hip blocked, 2-hip and knee blocked, 3-hip, knee and ankle blocked) on the operative limb while no detectable sensory or motor block was seen on the other limb.
At the end of the procedure, Group II patients received 20 ml dexmedetomidine solution containing dexmedetomidine as per the dose of 1 μg/kg via intra-articular route and Group I patients received 20 ml normal saline intra-articularly 10 min before the release of tourniquet. Intraoperative vitals: Heart rate, mean arterial pressure were noted at 5 min intervals for the first 30 min, then every 15 min till completion of surgery. Hypotension (decrease in mean arterial pressure >25% from baseline) was treated with intravenous fluids and ephedrine while bradycardia (heart rate <45 beats/min) was treated with atropine. Heart rate mean arterial pressure and pain scores were noted at 1, 2, 4, 6, 8, 12, 18, and 24 h postoperatively. Time of regression of the effect of spinal block to L2 level was also noted in each patient.
Intravenous diclofenac 75 mg was administered if the VAS pain score was ≥4 and repeated every 8 h. Tramadol 50 mg intravenous was given as rescue analgesia if the pain continued after administration of diclofenac. Time to first analgesic dose and total dose of diclofenac was recorded during the first 24 h in the postoperative period. Side effects such as nausea, vomiting, bradycardia, and hypotension were also noted.
Based on a pilot study with an assumption of a standard deviation of 10 mm, a group size of 25 patients in each group was found to be sufficient to have a power of 90% for comparing VAS at 5% level of significance.
| Results|| |
In this study, there was no statistically significant difference between the two groups in terms of age, weight, gender, and duration of surgery as shown in [Table 1].
When VAS scores of the two groups were compared, Group II patients who received intra-articular dexmedetomidine showed significantly lower VAS scores at 2, 4, 6, 8, 12, and 18 h compared to Group I patients who received volume matched normal saline [Figure 1].
Time to first analgesic dose was also compared between the two groups and it was observed that this time was significantly lesser in patients of Group I (244 ± 2.92) than Group II (308 ± 3.59) as shown in [Figure 2].
Time to regression of sensory block [Figure 3] and complete recovery of motor block [Figure 4] was also assessed and did not show statistically significant difference between the two groups.
The total requirement of diclofenac for analgesia for dexmedetomidine group (Group II) was significantly lower than that for the control group (Group I), 36 mg ± 7.65 for Group II and 129 mg ± 6.87 for Group I [Figure 5]. Overall in dexmedetomidine group only 12 patients required analgesia in the first 24 h postoperatively. None of the patients in dexmedetomidine group needed tramadol as rescue whereas 5 patients in the control group received 50 mg tramadol each as rescue analgesia.
| Discussion|| |
Arthroscopic knee procedures are commonly performed on an ambulatory setting or during a short hospital stay.  Postoperative analgesia is crucial for these patients as inadequate analgesia may hamper early discharge and early ambulation. 
In this study, we have used intra-articular dexmedetomidine for postoperative analgesia in patients undergoing arthroscopic knee procedures with unilateral spinal anesthesia as the anesthetic technique and observed the patients for 24 h postoperatively. The results in our study show that using intra-articular dexmedetomidine as a single dose has led to reduced incidence of postoperative pain, lesser total analgesic requirement, and prolongation of time to first analgesic dose requirement. Thus, a single dose of dexmedetomidine via intra-articular route provides adequate analgesia for arthroscopic knee procedures.
The mechanism of intra-articular analgesic action of dexmedetomidine is not clearly understood, but it might be similar to that suggested for clonidine. , Clonidine acts on alpha 2 adrenergic presynaptic receptor and inhibits release of norepinephrine at peripheral afferent nociceptors.  It also has local anesthetic effect by inhibiting nerve impulses through C and Ad fibers and analgesic effect via modulation of opioid analgesic pathway and may stimulate the release of enkephalin-like substance at peripheral sites. ,
Previous studies have used intra-articular dexmedetomidine ,,, and other drugs like clonidine,  morphine  and local anesthetics , in arthroscopic knee surgeries attaining good postoperative analgesia. The choice of anesthetic technique used was mostly general anesthesia whereas in our study we have used unilateral spinal anesthesia. The advantage of using unilateral spinal anesthesia is avoiding postoperative nausea, vomiting which commonly occurs in patients following general anesthesia.  Further, unilateral spinal anesthesia also minimizes the risk of hypotension and avoids motor block on nonoperative side as compared to bilateral spinal, thus making early discharge possible. ,
Al-Metwalli et al.  in 2008 performed a study comparing three groups using intra-articular dexmedetomidine, intravenous dexmedetomidine and placebo, and concluded that intra-articular dexmedetomidine in a dosa of 1 μg/kg enhanced postoperative pain relief and also reduced the need for postoperative analgesia and prolonged the time to first analgesic request. These results are in agreement with those of our study.
El-Hamamsy et al.  in 2009 compared intra-articular dexmedetomidine and fentanyl with bupivacaine 0.25% in a volume of 30 ml. patients were divided into three groups: Bupivacaine, bupivacaine with 1 μg/kg dexmedetomidine, and bupivacaine with 1 μg/kg fentanyl. They concluded that both dexmedetomidine and fentanyl in combination with bupivacaine resulted in decreased postoperative pain scores with an increased time to first analgesic request and a decreased need for postoperative analgesia as well as an increased duration of pain relief as compared with bupivacaine alone.
Paul et al.  in 2010 concluded that intra-articular dexmedetomidine added as an adjunct to ropivacaine in patients undergoing arthroscopic knee surgery improve the quality and duration of postoperative analgesia.
Alipour et al.  in 2014 evaluated the efficacy of intra-articular dexmedetomidine and concluded that intra-articular dexmedetomidine in a dose of 1 μg/kg alleviates postoperative pain, reducing the need for narcotics as analgesics and increases the time to first analgesic request.
Sun et al.  in a meta-analysis in 2012 assessed the efficacy and safety of a single dose intra-articular clonidine for postoperative pain following arthroscopic knee surgery and concluded analgesic effect is mild and short lasting, for just 4 h after injection suggesting that intra-articular clonidine alone could not provide sufficient postoperative analgesia. Postoperative hypotension was also observed that precluded its use in ambulatory settings. On the contrary, using intra-articular dexmedetomidine in our study provided more effective and prolonged analgesia without causing any hypotension in the postoperative period.
| Conclusion|| |
Use of intra-articular dexmedetomidine provides effective postoperative analgesia following arthroscopic knee surgery with a reduction in total analgesic dose requirement and a prolongation of time to need for first analgesic dose.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]