Intra-articular (IA) catheter administration of postoperative analgesics. A new trial design allows evaluation of baseline pain, demonstrates large variation in need of analgesics, and finds no analgesic effect of IA ketamine compared with IA saline

Efficacy and safety of ketamine as an adjuvant to regional anesthesia: A systematic review and meta-analysis of randomized controlled trials

STUDY OBJECTIVE

To identify whether adding ketamine to the local anesthetics (LA) in the regional anesthesia could prolong the duration of analgesia.

DESIGN

A Systematic review and meta-analysis of randomized controlled trials.

SETTING

The major dates were obtained in the operating room and the postoperative recovery ward.

PATIENTS

A total of 1011 patients at ASA physical status I and II were included in the analysis. Procedure performed including cesarean section, orthopedic, radical mastectomy, urological or lower abdominal surgery and intracavitary brachytherapy implants insertion.

INTERVENTIONS

After an extensive search of the electronic database, patients received regional anesthesia combined or not combined general anesthesia and with or without adding ketamine to LA were included in the analysis. The regional anesthesia includes spinal anesthesia, brachial plexus block, pectoral nerve block, transversus abdominis plane block and femoral and sciatic nerve block.

MEASUREMENT

The primary outcome was the duration of analgesia. Secondary outcomes were the duration and onset time of motor and sensory block as well as the ketamine-related adverse effect. Data are expressed in mean differences in continuous data and odds ratios (OR) for dichotomous data with 95% confidence intervals. The risk of bias of the included studies was evaluated using the revised Cochrane risk of bias tool for randomized trials. The quality of evidence for each outcome was rated according to the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) Working Group system.

MAIN RESULT

Twenty randomized controlled trials were included in the analysis. When ketamine was used as an adjuvant to LA, the duration of analgesia could be prolonged(172.21 min, 95% CI, 118.20 to 226.22; P<0.00001, I2 = 98%), especially in the peripheral nerve block(366.96 min, 95% CI, 154.19 to 579.74; P = 0.0007, I2 = 98%). Secondary outcomes showed ketamine could prolong the duration of sensory block(29.12 min, 95% CI, 10.22 to 48.01; P = 0.003, I2 = 96%) but no effect on the motor block(6.94 min, 95% CI,-2.65 to 16.53;P = 0.16, I2 = 84%), the onset time of motor and sensory block (motor onset time, -1.17 min, 95% CI, -2.67 to 0.34; P = 0.13, I2 = 100%; sensory onset time, -0.33 min, 95% CI,-0.87 to 0.20; P = 0.23, I2 = 96%) as well as the ketamine-related adverse effect(OR, 1.97, 95% CI,0.93 to 4.17;P = 0.08, I2 = 57%).

CONCLUSION

This study indicates that ketamine could be an ideal adjuvant to local anesthetics regardless of the types of anesthesia. Overall, the quality of the evidence is low.

Effects of intraarticular ketamine combined with periarticular bupivacaine on postoperative pain after arthroscopic meniscectomy

OBJECTIVES

This study aims to evaluate the effects of two different doses of intraarticular ketamine on visual analog scale (VAS) scores at rest and movement, time to first analgesic requirement, and 24-h morphine consumption in patients undergoing arthroscopic meniscectomy as well as to assess the frequency of postoperative nausea&vomiting, respiratory depression, pruritus, urinary retention, and constipation and to compare the time to discharge.

PATIENTS AND METHODS

This prospective randomized double-blind study was performed between August 2013 and August 2014 on 75 patients (32 males, 43 females; mean age 46.7±13 years; range, 18 to 75 years) with American Society of Anesthesiologists scores of I-II scheduled for unilateral meniscectomy. Patients were randomized to receive 0.5 mg.kg^-1 ketamine (group K1), 1 mg.kg^-1 ketamine (group K2) or saline (group S) to a total volume of 20 mL intraarticularly at the end of the surgery. All patients were performed periarticular 10 mL 0.5% bupivacaine infiltration. Visual analog scale at rest and during passive knee movement was used to evaluate pain both preoperatively and at postoperative 0, 30 min, and 1, 2, 4, 6, 12, and 24 h. Time to first analgesic requirement and morphine consumption were recorded.

RESULTS

Visual analog scale scores at rest and during movement at postoperative 0 were significantly reduced in group K2 compared with group S (p<0.05). The first analgesic requirement time was significantly longer in group K1 (76.9±25.2 min) and group K2 (93.4±26.1 min) than group S (29.3±7.1 min). Morphine consumption was lower in group K2 compared to group K1 and group S at postoperative 30 min, and 1 and 2 h. However, 24-h morphine consumption was similar in all groups.

CONCLUSION

Intraarticular injection of 0.5 mg.kg^-1 and 1 mg.kg^-1 ketamine for postoperative pain management provided similar analgesic efficacy. However, high dose ketamine more noticeably decreased opioid requirement in the early postoperative period.

Effects of intraarticular tramadol, magnesium and ketamine on postoperative pain in arthroscopic meniscectomy

Objective

Postoperative pain control is important in terms of early recovery and rehabilitation in arthroscopic meniscectomy. For this purpose, we aimed to compare the effects of intraarticular tramadol, magnesium, and ketamine with combinations of pericapsular bupivacaine on postoperative pain and recovery in arthroscopic meniscectomy.

Methods

Ninety patients who underwent arthroscopic meniscectomy were enrolled in the study. Group T was given tramadol, Group K was given ketamine, and Group M was given magnesium reconstituted intraarticularly, and all groups received periarticular bupivacaine. Comparisons were made in terms of the patients’ postoperative Visual Analogue Scale scores with and without movement, need for additional analgesics, first analgesic time, mobilization times, adverse effects, and satisfaction with the analgesics.

Results

The Visual Analogue Scale scores were lowest in Group T at 0 minutes, and were higher in the 15th and 30th minutes and 1st, 2nd, and 6th hours. Visual Analogue Scale values with movement were found to be high in Group M at 0 and 15 minutes, but they were found to be higher in group T in the 30th minute, 1st, 2nd and 6th hour. The groups were similar in terms of postoperative additional analgesic use, number of analgesic use, and satisfaction with analgesics; however, the first analgesic time was earlier in Group M, and the first mobilization time was earlier in Group K.

Conclusion

Intraarticular ketamine enables early mobilization and less need for additional analgesics, it also provides a better analgesic effect in comparison with intraarticular tramadol and magnesium.

[Effects of intraarticular tramadol, magnesium and ketamine on postoperative pain in arthroscopic meniscectomy]

OBJECTIVE

Postoperative pain control is important in terms of early recovery and rehabilitation in arthroscopic meniscectomy. For this purpose, we aimed to compare the effects of intraarticular tramadol, magnesium, and ketamine with combinations of pericapsular bupivacaine on postoperative pain and recovery in arthroscopic meniscectomy.

METHODS

Ninety patients who underwent arthroscopic meniscectomy were enrolled in the study. Group T was given tramadol, Group K was given ketamine, and Group M was given magnesium reconstituted intraarticularly, and all groups received periarticular bupivacaine. Comparisons were made in terms of the patients' postoperative Visual Analogue Scale scores with and without movement, need for additional analgesics, first analgesic time, mobilization times, adverse effects, and satisfaction with the analgesics.

RESULTS

The Visual Analogue Scale scores were lowest in Group T at 0 minutes, and were higher in the 15th and 30th minutes and 1st, 2nd, and 6th hours. Visual Analogue Scale values with movement were found to be high in Group M at 0 and 15 minutes, but they were found to be higher in group T in the 30th minute, 1st, 2nd and 6th hour. The groups were similar in terms of postoperative additional analgesic use, number of analgesic use, and satisfaction with analgesics; however, the first analgesic time was earlier in Group M, and the first mobilization time was earlier in Group K.

CONCLUSION

Intraarticular ketamine enables early mobilization and less need for additional analgesics, it also provides a better analgesic effect in comparison with intraarticular tramadol and magnesium.

Randomized controlled trial of intra-articular ketorolac on pain and inflammation after minor arthroscopic knee surgery

BACKGROUND

Ketorolac is an effective non-steroidal anti-inflammatory drug, commonly used with local anaesthetics as part of local infiltration analgesia protocols following orthopaedic surgery. However, systemic uptake and drug action may be the major mechanism after local infiltration. The aims of this project were to study the effects of a small, systemically ineffective dose of ketorolac given intra-articularly for post-operative pain and also to study synovial inflammatory biomarkers. We investigated whether ketorolac affects pro-inflammatory biomarkers in an in vitro model, as well.

METHODS

In this placebo-controlled, blind, randomized study, we analysed intra-articular ketorolac (5 mg) in ambulatory minor knee surgery patients with moderate or severe pain (n = 44). We assessed post-operative pain intensity (n = 44) and analysed microdialysis samples taken from knee synovial tissue every 20 min (n = 34). We also tested cyclooxygenase-independent effects of ketorolac in synovial cells stimulated by prostaglandin E₂ and chondroitin sulphate in vitro.

RESULTS

Intra-articular ketorolac (5 mg) administration did not reduce pain or synovial pro-inflammatory cytokines CXCL1, IL-8, and MCP-1, 0-120 min after knee arthroscopy. Female gender was a risk factor for moderate or severe pain (relative risk 1.45, 95% confidence interval 1.04-2.01). Paradoxically, ketorolac increased the release of CXCL1 and IL-8 in prostaglandin E₂ and chondroitin sulphate-stimulated synovial cells in vitro.

CONCLUSION

Ketorolac prescribed at a low dose intra-articularly does not produce any detectable analgesic effect after minor knee surgery.

Women report higher pain intensity at a lower level of inflammation after knee surgery compared with men

Women report more pain than men after arthroscopic surgery, but analyses of pro-inflammatory cytokines indicates higher male concentrations of pain biomarkers in synovial fluid.

Introduction and Objectives:

We previously found that women report more pain after knee arthroscopic procedures than men. It remains unclear whether this is due to different biochemical responses or nociceptive mechanisms.

Methods:

We analyzed acute pain-related inflammatory markers in a clinical model of patient self-reported pain immediately after knee surgery. To simultaneously measure 92 inflammatory biomarkers, we used the proximity extension assay with the Proseek Multiplex Inflammation I panel (Olink Bioscience, Uppsala, Sweden). Knee surgery was performed under general anesthesia with propofol and remifentanil. Analgesic drugs were only administered on patient request.

Results:

Women were 4.9 times more likely to report moderate or severe pain than men (95% confidence interval, 1.2–19.6, P = 0.024). Patient age, preoperative pain, and surgery duration were not significant factors. We analyzed synovial fluids from 44 patients (23 women, 21 men). After false discovery rate correction, MMP-10 was the only biomarker that was higher among men (P = 0.01). Linear discriminant analysis showed that 3 proteins (IL-8, CCL-4, and MCP-2) were expressed at higher levels in men, with differences of >1 normalized protein expression. No proteins were overexpressed by >1 normalized protein expression in women.

Conclusion:

Acute pain after knee arthroscopy was more intense in women, but pro-inflammatory biomarkers and MMP-10 were higher in men. Further knowledge of cytokine function is required before concluding that the disparities in biomarker expression are clinically unimportant. The similar biochemical signaling between sexes suggests that central mechanisms are of greater importance in sex-specific joint pain perception.

Single dose intra-articular morphine for pain control after knee arthroscopy

BACKGROUND

Knee arthroscopy is a common procedure and is associated with postoperative pain. Intra-articular (IA) injection of morphine for pain control has been widely studied, but its analgesic effect after knee arthroscopy is uncertain.

OBJECTIVES

To evaluate the relative effects on pain relief and adverse events of IA morphine given for pain control after knee arthroscopy compared with placebo, other analgesics (local anaesthetics, non-steroidal anti-inflammatory drugs (NSAIDs), other opioids) and other routes of morphine administration.

SEARCH METHODS

We searched CENTRAL (The Cochrane Library Issue 4, 2015), MEDLINE via Ovid (January 1966 to May 2015), EMBASE via Ovid (January 1988 to May 2015), and the reference lists of included articles. We also searched the metaRegister of controlled trials, clinicaltrials.gov and the World Health Organization (WHO) International Clinical Trials Registry Platform for ongoing trials.

SELECTION CRITERIA

We identified all the randomised, double-blind controlled trials that compared single dose IA morphine with other interventions for the treatment of postoperative pain after knee arthroscopy. We excluded studies with fewer than 10 participants in each group, using spinal or epidural anaesthesia, or assessing the analgesic effect of IA morphine on chronic pain.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed the quality of each trial and extracted information on pain intensity, supplementary analgesics consumption and adverse events. We assessed the evidence using GRADE (Grading of Recommendations Assessment, Development and Evaluation) and created 'Summary of findings' tables.

MAIN RESULTS

We included 28 small, low quality studies (29 reports) involving 2564 participants. Of 20 studies (21 reports) comparing morphine with placebo, nine studies with adequate data were included in the meta-analysis. Overall, the risk of bias was unclear. Overall, the quality of the evidence assessed using GRADE was low to very low, downgraded primarily due to risk of bias, small study size, and imprecision.No statistical difference was found between 1 mg IA morphine and placebo in pain intensity (visual analogue scale (VAS)) at early phase (zero to two hours) (mean difference (MD) -0.50, 95% CI -1.15 to 0.14; participants = 297; studies = 7; low quality evidence), medium phase (two to six hours) (MD -0.47, 95% CI -1.09 to 0.14; participants = 297; studies = 7; low quality evidence) and late phase (six to 30 hours) (MD -0.88, 95% CI -1.81 to 0.04; participants = 297; studies = 7; low quality evidence). No significant difference was found between 1 mg and 2 mg morphine for pain intensity at early phase (MD -0.56, 95% CI -1.93 to 0.81; participants = 105; studies = 2; low quality evidence), while 4 mg/5 mg morphine provided better analgesia than 1 mg morphine at late phase (MD 0.67, 95% CI 0.08 to 1.25; participants = 97; studies = 3; low quality evidence). IA morphine was not better than local anaesthetic agents at early phase (MD 1.43, 95% CI 0.49 to 2.37; participants = 248; studies = 5; low quality evidence), NSAIDs at early phase (MD 0.95, 95% CI -0.95 to 2.85; participants = 80; studies = 2; very low quality evidence), sufentanil, fentanyl or pethidine for pain intensity. IA morphine was similar to intramuscular (IM) morphine for pain intensity at early phase (MD 0.21, 95% CI -0.48 to 0.90; participants = 72; studies = 2; very low quality evidence).Meta-analysis indicated that there was no difference between IA morphine and placebo or bupivacaine in time to first analgesic request. Eleven out of 20 studies comparing morphine with placebo reported adverse events and no statistical difference was obtained regarding the incidence of adverse events (risk ratio (RR) 1.09, 95% CI 0.51 to 2.36; participants = 314; studies = 8; low quality evidence). Seven of 28 studies reported participants' withdrawal. There were not enough data for withdrawals to be able to perform meta-analysis.

AUTHORS' CONCLUSIONS

We have not found high quality evidence that 1 mg IA morphine is better than placebo at reducing pain intensity at early, medium or late phases. No statistical difference was reported between IA morphine and placebo regarding the incidence of adverse events. The relative effects of 1 mg morphine when compared with IA bupivacaine, NSAIDs, sufentanil, fentanyl and pethidine are uncertain. The quality of the evidence is limited by high risk of bias and small size of the included studies, which might bias the results. More high quality studies are needed to get more conclusive results.

Effect of preemptive intra-articular morphine and ketamine on pain after arthroscopic rotator cuff repair: a prospective, double-blind, randomized controlled study

BACKGROUND

Rotator cuff tear is a leading etiology of shoulder pain and disability. Surgical treatment is indicated in patients with persistent pain who fail a trial of non-surgical treatment. Pain reduction following rotator cuff repair, particularly within the first 24-48 h, is a major concern to both doctors and patients. This study aimed to compare the postoperative antinociceptive additive effects of pre-incisional intra-articular (IA) ketamine when combined with morphine with two times the dose of morphine or saline.

METHODS

In this prospective, randomized, double blind, controlled trial patients undergoing arthroscopic rotator cuff tear repair (ARCR) under general anesthesia were enrolled. Patients were randomly assigned to one of the three intervention groups. Twenty minutes prior to incision, morphine (20 mg/10 ml), ketamine (50 mg + morphine 10 mg/10 ml), or saline (0.9 % 10 ml) (n = 15/group), were administered to all patients. First 24 h postoperative analgesia consisted of intravenous patient controlled analgesia (IV-PCA) morphine and oral rescue paracetamol 1000 mg or oxycodone 5 mg. 24-h, 2-week and 3-month patient rated pain numeric rating scale (NRS) and analgesics consumption were documented.

RESULTS

Patients' demographic and perioperative data were similar among all groups. The 24-h and the 2-week NRSs were significantly (p < 0.05) lower in both treatment groups compared to placebo, but were not significantly different between the two intervention groups. PCA-morphine and oral analgesics were consumed similarly among the groups throughout the study phases.

CONCLUSIONS

Pre-incisional intra-articular morphine reduced pain in the first 2 weeks after arthroscopic rotator cuff repair. Further research is warranted to elucidate the optimal timing and dosing of IA ketamine and morphine for postoperative analgesic effects.

Role of ketamine in acute postoperative pain management: a narrative review

OBJECTIVES

The objective of this narrative review was to examine the usage of ketamine as a postoperative analgesic agent across a wide variety of surgeries.

DESIGN

A literature search was performed using the phrases "ketamine" and "postoperative pain." The authors analyzed the studies that involved testing ketamine's effectiveness at controlling postoperative pain. Effectiveness was assessed through various outcomes such as the amount of opiate consumption, visual analog scale (VAS) pain scores, and persistent postoperative pain at long-term follow-up.

RESULTS

While many different administration protocols were evaluated, delivering ketamine both as a pre- or perioperative bolus and postoperative infusion for up to 48 hours appeared to be the most effective. These effects are dose-dependent. However, a number of studies analyzed showed no benefit in using ketamine versus placebo for controlling postoperative pain. While ketamine is a safe and well-tolerated drug, it does have adverse effects, and there are concerns for possible neurotoxicity and effects on memory.

CONCLUSIONS

In a number of limited situations, ketamine has shown some efficacy in controlling postoperative pain and decreasing opioid consumption. More randomized controlled trials are necessary to determine the surgical procedures and administrations (i.e., intravenous, epidural) that ketamine is best suited for.

Efficacy of intraarticular application of ketamine or ketamine-levobupivacaine combination on post-operative pain after arthroscopic meniscectomy

PURPOSE

To evaluate the efficacy of intraarticular injection of ketamine or ketamine plus levobupivacaine on post-operative analgesia in patients undergoing arthroscopic meniscectomy.

METHODS

A prospective, randomized, double-blind study was performed on 60 patients aged 18-65 years who planned to undergo elective arthroscopic meniscectomy. The patients were divided into three groups: the ketamine group (n = 20) received 1.0 mg/kg of intraarticular ketamine in 20 ml of normal saline, the ketamine-levobupivacaine group (n = 20) received 0.5 mg/kg of intraarticular ketamine plus 50.0 mg of 0.25 % levobupivacaine in 20 ml of normal saline, and the control group (n = 20) received 20 ml of intraarticular normal saline. A visual analogue scale (VAS) was used to determine the efficacy of analgesia at 1, 2, 4, 6, 8, 12, and 24 h post-operatively.

RESULTS

There were statistically significant differences in the median VAS scores among the three groups according to Bonferroni adjustment at all time points (p < 0.01), with the exception of 6 and 24 h post-operatively. The median VAS scores at 1, 2, and 4 h post-operatively were higher in the control group than in the two treatment groups (p < 0.001). The median VAS scores in the control group at 1, 2, 4, 6, 8, and 12 h post-operatively and those in the ketamine group at 4, 8, and 12 h post-operatively were significantly higher than those in the ketamine-levobupivacaine group (p < 0.05).

CONCLUSION

Intraarticular ketamine provides effective post-operative analgesia. Addition of intraarticular levobupivacaine to ketamine may provide better amelioration of pain after outpatient arthroscopic meniscectomy.

Effect of ketamine as an adjuvant in ultrasound-guided supraclavicular brachial plexus block: A double-blind randomized clinical trial study

Background:

Supraclavicular brachial plexus block is one of the most effective anesthetic procedures in operations for the upper extremity. Ketamine has been reported to enhance the analgesic effects of local anesthetics. We have conducted this study to assess whether coadministration of ketamine can prolong the local analgesic effect of lidocaine in the supraclavicular brachial plexus block for patients undergoing elective upper extremity surgery.

Materials and Methods:

Sixty adult patients undergoing elective surgery of the elbow, forearm, wrist or hand were randomly allocated in two groups of 30 patients each. Group 1 (ketamine group) received 5 mg/kg lidocaine 1.5% plus 2 mg/kg ketamine, Group 2 (control group) received 5 mg/kg lidocaine 1.5% and saline. The outcome measures included severity of pain by using visual analog scale (VAS, 0 = no pain 10 cm = the most severe pain), time of first request for analgesia, and total dose of postoperative opioid administration. The data was analyzed using the χ² test, student's t-test, Kaplan-Meier survival analysis, and Multivariate analysis tests.

Results:

Patients in the control group had a higher VAS than patients who received ketamine, at all time points during the first 24 hours after surgery (all P < 0.05). The time of first request for analgesia in the ketamine group was significantly more than in the control group (8.93 ± 1.0 vs. 7.30 ± 1.9, respectively, P < 0.001).

Conclusion:

The addition of ketamine to lidocaine in the ultrasound-guided brachial plexus block could decrease the postoperative pain and need for analgesic. Therefore, it could be considered as an option in the brachial plexus block to enhance the analgesic action of lidocaine.

Ketamine is toxic to chondrocyte cell cultures

Ketamine has been used in combination with a variety of other agents for intra-articular analgesia, with promising results. However, although it has been shown to be toxic to various types of cell, there is no available information on the effects of ketamine on chondrocytes.

We conducted a prospective randomised controlled study to evaluate the effects of ketamine on cultured chondrocytes isolated from rat articular cartilage. The cultured cells were treated with 0.125 mM, 0.250 mM, 0.5 mM, 1 mM and 2 mM of ketamine respectively for 6 h, 24 hours and 48 hours, and compared with controls. Changes of apoptosis were evaluated using fluorescence microscopy with a 490 nm excitation wavelength. Apoptosis and eventual necrosis were seen at each concentration. The percentage viability of the cells was inversely proportional to both the duration and dose of treatment (p = 0.002 and p = 0.009). Doses of 0.5 mM, 1 mM and 2mM were absolutely toxic.

We concluded that in the absence of solid data to support the efficacy of intra-articular ketamine for the control of pain, and the toxic effects of ketamine on cultured chondrocytes shown by this study, intra-articular ketamine, either alone or in combination with other agents, should not be used to control pain.

Cite this article: Bone Joint J 2014; 96-B:989–94.

Intra-articular morphine enhances analgesic efficacy of ropivacaine for knee arthroscopy in ambulatory patients

The aim of this double-blind, randomized control trial was to compare the effectiveness of intra-articular ropivacaine alone or with morphine or ketoprofen for controlling pain after arthroscopic knee surgery. One hundred fifty-six patients scheduled for elective knee arthroscopy were recruited. All patients received general anesthesia and were randomly assigned to 4 groups to receive intra-articular ropivacaine 40 mg (group R), ropivacaine 24 mg plus morphine 8 mg (group R+M), ropivacaine 36 mg plus ketoprofen 100 mg (group R+K), or normal saline (group N/S). Pain, sedation, orientation, nausea, vomiting, and urine retention were recorded at 0, 1, 2, 4, 8, 12, and 24 hours postoperatively. Pain was evaluated by a 10-cm visual analog scale (VAS). When the pain was >2, a suppository of 400 mg paracetamol plus 10 mg codeine plus 50 mg caffeine was given. Results showed that at 4 hours postoperatively, pain differed significantly among the 4 groups (P<.001), with less pain recorded in the R+M group. Similarly, the number of suppositories administered postoperatively to the R+M group was significantly less (P<.001) vs the other groups. Patients who received ropivacaine and morphine or normal saline had a higher incidence of nausea and vomiting vs the other groups (P=.001 and P=.036, respectively). The combination of intra-articular ropivacaine and morphine is associated with less pain after knee arthroscopy during early recovery but with a higher incidence of nausea and vomiting. However, the addition of ketoprofen to ropivacaine provides relatively satisfactory pain relief, but with fewer side effects compared to morphine.

The effect of intraarticular combinations of tramadol and ropivacaine with ketamine on postoperative pain after arthroscopic meniscectomy

INTRODUCTION

The purpose of this prospective randomized study was to evaluate the effects of intraarticular combinations of tramadol and ropivacaine with ketamine in postoperative pain control of patients undergoing arthroscopic meniscectomy.

MATERIALS AND METHODS

We randomly divided 80 patients into four groups to receive intraarticular 50 mg tramadol (Group T), 50 mg tramadol with 0.5 mg kg(-1) ketamine (Group TK), 75 mg ropivacaine (Group R), 75 mg ropivacaine with 0.5 mg kg(-1) ketamine (Group RK) in 20 ml normal saline at the end of surgery. Postoperative analgesia was provided with patient-controlled analgesia with morphine. Postoperative pain scores, total morphine consumption amount and side effects were recorded at intervals of 0, 1, 2, 4, 8, 12 and 24 h after the operation.

RESULTS

Pain scores were higher in Group T when compared with Group R and Group RK at second and fourth hours, also compared with Group RK at zeroth, first, second, fourth and eighth hours. Total morphine consumption amount was found to be higher in Group T when compared to Group TK at eighth and twelfth hours and Group RK at eighth hours (P < 0.05). Total morphine consumption was lowest in Group TK (P < 0.05). There were no significant differences among the study groups regarding side effects.

CONCLUSIONS

Administration of intraarticular tramadol-ketamine combination was found to be more effective in decreasing postoperative daily analgesic consumption.

Post-operative pain after knee arthroscopy and related factors

The aim of this study was to explore the intensity of post-arthroscopy knee pain during the first 24 hours, and to study the influence of pre-operative pain, tourniquet time and amount of surgical trauma on post-arthroscopy pain. In 78 male patients that underwent elective arthroscopic menisectomy or diagnostic arthroscopy of the knee, preoperative and post-operative pain were registered using the Visual Analogue Scale. Variance for repeated measures and for independent observations was analysed. Supplementary analgesia was required for 23% of the patients, more often in the recovery room and between 2 and 8 hours postoperatively. Of all factors analyzed, only time was statistically significant in determining the level of post-operative pain. Supplementary analgesia was required only in patients that underwent operative arthroscopy, and more often in patients with tourniquet time of more than 40 minutes. In conclusions, post-operative time is the most significant factor related to the post-arthroscopy knee pain.

Assessment of pain

Valid and reliable assessment of pain is essential for both clinical trials and effective pain management. The nature of pain makes objective measurement impossible. Acute pain can be reliably assessed, both at rest (important for comfort) and during movement (important for function and risk of postoperative complications), with one-dimensional tools such as numeric rating scales or visual analogue scales. Both these are more powerful in detecting changes in pain intensity than a verbal categorical rating scale. In acute pain trials, assessment of baseline pain must ensure sufficient pain intensity for the trial to detect meaningful treatment effects. Chronic pain assessment and its impact on physical, emotional, and social functions require multidimensional qualitative tools and health-related quality of life instruments. Several disease- and patient-specific functional scales are useful, such as the Western Ontario and MacMaster Universities for osteoarthritis, and several neuropathic pain screening tools. The Initiative on

METHODS

Measurement, and Pain Assessment in Clinical Trials recommendations for outcome measurements of chronic pain trials are also useful for routine assessment. Cancer pain assessment is complicated by a number of other bodily and mental symptoms such as fatigue and depression, all affecting quality of life. It is noteworthy that quality of life reported by chronic pain patients can be as much affected as that of terminal cancer patients. Any assessment of pain must take into account other factors, such as cognitive impairment or dementia, and assessment tools validated in the specific patient groups being studied.

Pain and disability 1 year after knee arthroscopic procedures

BACKGROUND

Persistent chronic pain after surgery is a major health care problem. Its prevalence after knee arthroscopy is unknown. We conducted a follow-up of knee arthroscopy patients. The aims were to estimate the prevalence of pain at rest and during activity 1 year after knee arthroscopy.

METHODS

One hundred patients with moderate or severe acute pain after knee arthroscopy were included in one of two randomized-controlled pain trials. A questionnaire was mailed to all the patients 1 year after inclusion.

RESULTS

The prevalence of pain at rest 1 year after surgery [numeric rating scale (NRS) 0-10 grade >/=1] was 30% (95% CI 17-47) in women and 29% (95% CI 17-46) in men. Four of 33 female (10%) and three of 34 male patients (9%) experienced pain intensities at rest of NRS>4, and the number of patients who had experienced NRS>4 during activities were 7 (21%) and 4 (11%), respectively. Age above 50 years was positively correlated to persistent pain. The number of patients who reported a reduced activity of daily living (ADL) due to pain (NRS>4) was 14 of 33 (42%, 95% CI 28-56%) in female and five of 34 (15%, 95% CI 5-25%) in male patients (P=0.03). Age above 50 years was positively correlated to impaired ADL function due to knee pain.

CONCLUSIONS

Persistent pain after knee arthroscopy may be a significant health care problem. Age and female gender are independent risk factors for pain and disability 1 year after surgery.

The role of ketamine in pain management

Ketamine is a dissociative anaesthetic; its mechanism of action is primarily an antagonism of the N-methyl-D-aspartate (NMDA) receptor. The role of ketamine, in particular in lower sub-anaesthetic doses, has recently gained increasing interest in pain management. It has been studied in a considerable number of trials and analysed in meta-analyses and systematic reviews. Based on these data, the primary role of ketamine in such low doses is as an 'anti-hyperalgesic', 'anti-allodynic' or 'tolerance-protective' agent. It therefore has a role in the treatment of opioid resistant or 'pathological' pain (central sensitisation with hyperalgesia or allodynia, opioid induced hyperalgesia, neuropathic pain) rather than as an 'analgesic' in its own right. Low dose ketamine also has 'preventive analgesia' properties. Furthermore, in higher doses it provides effective and safe sedation and analgesia for painful procedures. The place of ketamine in the treatment of chronic pain and the effects of long-term medicinal use remain unclear.

[Potential applications and significance of peripheral opioid analgesia]

Recently, the local application of analgesic substances has attracted much interest and has become increasingly relevant in daily clinical practice. The lack of the well-known therapy-limiting central side effects of systemically administered opioids is a clear advantage of "peripheral opioid analgesia". Important prerequisites for the occurrence of peripheral analgesic effects of opioids are good accessibility of the painful site, presence of clinically relevant pain, signs of a local inflammation, exclusion of a fast systemic absorption, and adequately potent analgesic substances. This review gives an outline of recent experience with various clinical applications of "peripheral opioid analgesia".

Gender is a confounding factor in pain trials: women report more pain than men after arthroscopic surgery

A gender difference in the incidence of acute pain may be a confounder in analgesic trials. We have tested the hypothesis that the incidence of acute pain after knee arthroscopic procedures is greater in women than men. We performed three RCTs on intra-articular analgesics in which no postoperative analgesia was given until the need for such treatment was documented by scoring moderate-to-severe pain on a verbal rating scale (VRS 0-4; n=219), and a 0-100 mm visual analogue pain scale (VAS) within 2 h postoperatively. All trials were performed with an intra-articular catheter technique. The design allowed us to study the natural course of pain after arthroscopic surgery until analgesia was required. Women reported more pain of at least moderate intensity than men (84 vs 57%; P<0.0001), indicating that being female is a risk factor for early postoperative pain (RR 1.47, 95% confidence interval from 1.23 to 1.74). The VAS score corresponding to moderate and severe pain is similar in men and women. Only short acting anaesthetics were given in order to minimise carry-over effects. Since previous trials on arthroscopic analgesics neither measured baseline pain nor stratified for gender, a difference between treatment groups could result from an uneven distribution regarding these factors. Our findings have major implications for the interpretation of previously published trials on intra-articular analgesia.

Ketamine and postoperative pain – a quantitative systematic review of randomised trials

Ketamine, an N-methyl-D-aspartate receptor antagonist, is known to be analgesic and to induce psychomimetic effects. Benefits and risks of ketamine for the control of postoperative pain are not well understood. We systematically searched for randomised comparisons of ketamine with inactive controls in surgical patients, reporting on pain outcomes, opioid sparing, and adverse effects. Data were combined using a fixed effect model. Fifty-three trials (2839 patients) from 25 countries reported on a large variety of different ketamine regimens and surgical settings. Sixteen studies tested prophylactic intravenous ketamine (median dose 0.4 mg/kg, range (0.1-1.6)) in 850 adults. Weighted mean difference (WMD) for postoperative pain intensity (0-10 cm visual analogue scale) was -0.89 cm at 6 h, -0.42 at 12 h, -0.35 at 24 h and -0.27 at 48 h. Cumulative morphine consumption at 24 h was significantly decreased with ketamine (WMD -15.7 mg). There was no difference in morphine-related adverse effects. The other 37 trials tested in adults or children, prophylactic or therapeutic ketamine orally, intramuscularly, subcutaneously, intra-articulary, caudally, epidurally, transdermally, peripherally or added to a PCA device; meta-analyses were deemed inappropriate. The highest risk of hallucinations was in awake or sedated patients receiving ketamine without benzodiazepine; compared with controls, the odds ratio (OR) was 2.32 (95%CI, 1.09-4.92), number-needed-to-harm (NNH) 21. In patients undergoing general anaesthesia, the incidence of hallucinations was low and independent of benzodiazepine premedication; OR 1.49 (95%CI 0.18-12.6), NNH 286. Despite many published randomised trials, the role of ketamine, as a component of perioperative analgesia, remains unclear.

Moderate-to-Severe Pain After Knee Arthroscopy Is Relieved by Intraarticular Saline: A Randomized Controlled Trial

We have previously studied intraarticular (IA) analgesics compared with saline 10 mL in 2 randomized clinical trials. The patients who were given IA saline experienced rapid pain relief. Hypothetically, saline may produce a local analgesic effect by cooling or by diluting IA algogenic substances. This randomized double-blind study compared the analgesic effect of IA saline 10 mL with saline 1 mL, which should be a pure placebo. A soft catheter was left IA in 79 patients. We included 60 patients who developed moderate-to-severe pain within 1 h after knee arthroscopy under general anesthesia. A randomized, double-blind controlled comparison of IA saline 10 mL with saline 1 mL followed. Outcome measures were pain intensity, pain relief, and analgesic consumption. Within 1 h pain intensity decreased in both groups from approximately 50 to approximately 27 on a 0-100 mm visual analog scale. Pain intensity remained low and other pain outcome measures were similar during the 36-h observation period. The patients experienced equally good pain relief after IA injection of saline 10 mL and 1 mL. Our finding of a major placebo effect may have implications for the interpretation of previously published placebo-controlled IA analgesia studies.

IMPLICATIONS

In a randomized controlled trial we showed that pain after knee arthroscopy is modest and short-lived and can successfully be treated with intraarticular saline as placebo.

Effective pain relief from intra-articular saline with or without morphine 2 mg in patients with moderate-to-severe pain after knee arthroscopy: a randomized, double-blind controlled clinical study

BACKGROUND

Intra-articular (IA) morphine has given good and prolonged pain relief in some studies when given at the end of arthroscopic procedures in the knee joint. However, similar studies have not been able to document any local analgesic effect of morphine. A large number of the negative studies have not demonstrated any assay sensitivity. We have documented that around 40% of patients have only very mild or no pain after arthroscopic procedures in the knee joint. This obviously is a confounding factor, reducing assay sensitivity when all patients are included in IA morphine studies.

METHOD

By leaving a soft catheter IA in 57 patients and including only patients who developed moderate-to-severe pain within 1 h after an arthroscopic procedure in the knee joint under general anaesthesia, we included 40 patients. These patients had a mean pre-treatment baseline pain of about 50/100 on a 100-mm visual analogue scale (VAS) for pain intensity. A randomized, double-blind controlled comparison of saline 10 ml with or without morphine 2 mg followed. Test drugs were administered through the IA catheter. Pain intensity and pain relief, consumption of rescue analgesics and global evaluation of effect and adverse effects were measured up to 36 h thereafter.

RESULTS

Pain intensity decreased from about 50 to about 10-15/100 in both groups and the sum of pain intensity differences at 2 and 22 h was not significantly different between the two groups. Global evaluation of effects and adverse effects, as well as consumption of rescue analgesics during 36 h after arthroscopic procedures, were also similar in the two groups.

CONCLUSIONS

Only 70% of 57 patients had pain of moderate-to-severe intensity within 1 h after an arthroscopic procedure of the knee joint under general anaesthesia. IA injection of saline 10 ml and saline 10 ml with morphine 2 mg were both associated with pain relief. These findings may have implications for interpretations of a majority of published studies on IA morphine.