***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Reports on pain relief with intra-articular morphine  after arthroscopic knee operation are conflicting . To assess the long-term antinociceptive effect of intraarticular morphine , we studied pain at rest , pain on st and ing and ability to walk for 7 days after intraarticular injection of bupivacaine 100 mg  ( group 1 , n = 11 ) , bupivacaine 100 mg and morphine 1 mg ( group 2 , n = 10 ) and bupivacaine 100 mg and morphine 3 mg ( group 3 , n = 10 ) at the end of operation . Pain and walking were assessed by visual analogue and walking scales , respectively . Pain was treated with morphine i.v . in the recovery room and Tylenol No. 3 after discharge . Assessment s were made before operation , and 1 , 3 , 6 and 12 h after injection and on days 1 - 7 after operation . There were significant differences between the groups in pain scores ( pain at rest , P < 0.05 ; pain on st and ing , P < 0.01 ) . The pain scores in group 3 were lower than those in group 1 . The differences in pain scores at rest were significant at 12 h and on day 1 after operation and differences in pain scores on st and ing were significant at 12 h and on days 1 and 2 after operation . The scores in group 2 were intermediate between those in groups 1 and 3 . The walking scores in group 3 were significantly better than those in group 1 at 12 h. The amount of analgesics received in groups 2 and 3 was significantly less than that in group 1 until day 3 after operation . ( ABSTRACT TRUNCATED AT 250 WORDS PURPOSE The aim of the study was to compare the analgesic effect of 5 mg intra-articular ( IA ) morphine with 50 mg IA tramadol . TYPE OF STUDY Prospect i ve double-blind r and omized trial . METHODS Seventy-five patients having elective arthroscopic surgery of the knee were r and omized to receive IA tramadol 50 mg ( tramadol group ) , IA morphine 5 mg ( morphine group ) , or IA normal saline ( control group ) , in equivalent volumes ( 20 mL ) . The tourniquet was released 10 minutes after analgesic administration . Verbal pain rating score between 0 and 10 ( VRS ) , supplemental analgesic requirements , and incidence of side effects were recorded postoperatively . RESULTS Results are given as ( median [ 5 - 95 percentiles ] ) . The control group had a significantly shorter time to first analgesic request ( 25 min [ 15 - 55 ] ) than morphine group , ( 34 min [ 15 - 158 ] , P < .008 ) and the tramadol group , ( 33 min [ 17 - 728 ] , P < .008 ) . The patients in the control group complained of more severe pain ( VRS 7 [ 4 - 10 ] ) when they arrived at the postanesthesia care unit compared with the morphine group ( VRS 1 [ 0 - 9 ] , P = .002 ) and with the tramadol group ( VRS 0 [ 0 - 9 ] , P = .002 ) . These treatment benefits were especially prominent in the patients who had meniscectomy or in the subgroup of patients with more than 6 months of preoperative pain . There was no statistical difference between the tramadol and morphine groups in the time to first analgesia , postoperative pain scores after arrival at the postanesthesia care unit , consumption of rescue analgesic , or side effects . CONCLUSIONS We conclude that 50 mg IA tramadol provides analgesia equivalent to 5 mg IA morphine . LEVEL OF EVIDENCE Level II , r and omized controlled trial that shows no significant difference and lacks narrow confidence intervals We performed a r and omised double-blind controlled study in patients undergoing elective knee arthroscopy  to assess the effect of intra-articular morphine on postoperative pain relief . Patients in the study group ( n = 10 ) received 5 mg of morphine in a 25 ml dilution intra-articularly while those in the control group ( n = 10 ) received 25 ml of saline .  Postoperative pain was assessed at intervals by a visual analogue scale and the requirement for supplementary analgesia was recorded . Those in the study group had significantly lower pain scores and required less systemic analgesics than those in the control group . Plasma profiles for morphine and its metabolites were assayed and showed that they were too low to produce effective analgesia . Evidence suggests that analgesia was mediated by local action within the joint Abstract This prospect i ve , r and omized , double-blind study was carried out with 320 patients , subdivided into 4 groups of 80 patients each , who underwent arthroscopic knee surgery during the time period from March 1995 to February 1997 . Each of the 4 groups received a different solution : 15 ml of bupivacaine 0.5 % , 5 mg of morphine in 15 ml of isotonic saline solution , 15 ml of bupivacaine 0.5 % with epinephrine 0.0005 % , or 15 ml of isotonic saline solution ( control group ) . Within each study group , the following operations were performed : 15 cruciate ligament plasties with autologous patellar tendon grafts , 30  meniscus resections , 15  notch-plasties as preparation for anterior cruciate ligament surgery , and 20 other types of operation ( plica resection , diagnostic biopsy , etc . ) . Pain intensity was assessed with the visual analogue scale obtained from question ing patients at 2 , 4 , 8 , 12 , and 24 h postoperatively . In terms of reducing postoperative pain and decreasing the consumption of analgesics after arthroscopic knee surgery , bupivacaine 0.5 % with epinephrine 0.0005 % was found to be the most effective Praxis und Belegkliniken ffir Spezielle Orthop ~ dische Chirurgie , Mfinchen-Unterhaching , Germany 2 Department of Anaesthesiology and Critical Care Medicine , Johns Hopkins University , Baltimore , Maryl and , USA 3 Department of Neuropharmacology , Max-Planck-Institut ftir Psychiatrie , Planegg-Martinsried , Germany 4 Department of Biostatistics , Max-Planck-Institut ftir Psychiatrie , Planegg-Martinsried , We conducted a r and omized , placebo-controlled , double blinded study to compare the analgesic effects of intraarticular neostigmine , morphine , tenoxicam , clonidine and bupivacaine in 150 patients undergoing arthroscopic knee surgery . General anaesthesia protocol was same in all patients . At the end of the surgical procedure , patients were r and omized into six intraarticular groups equally . Group N received 500 μg neostigmine , Group M received 2 mg morphine , Group T received 20 mg tenoxicam , Group C received 1 μg kg−1 clonidine , Group B received 100 mg bupivacaine and Group S received saline 20 ml  . Visual analog scale scores 0 , 30 and 60 min and 2 , 4 , 6 , 12 , 24 , 48 and 72 h , time to first analgesic need , analgesic consumption at 48 h and 72 h and side effects were noted . Demographic and operational parameters were similar in six groups . All study groups provided analgesia when compared with saline group ( P<0.05 ) . Duration of analgesia in Group N and C was longer than other groups ( P<0.001 ) . Analgesic consumptions of Group N , C and T were lower than other groups ( P<0.01 ) . Pain scores during 2 h postoperatively were lower in all study groups than the control group ( P<0.001 ) . In Group B , median pain scores were higher than Groups N and C at 0 min and 30 min postoperatively ( P<0.001 ) . Side effects were not significantly different among the six groups . We conclude that the most effective drugs that are administered intraarticularly are neostigmine and clonidine among the five drugs we studied . Tenoxicam provided longer analgesia when compared with morphine and bupivacaine , postoperatively This present study investigated the effects of intraarticular morphine administration in 1 mg and 5 mg doses on post-operative pain relief and analgesic requirements for patients undergoing arthroscopic procedures . At the end of the operation patients were r and omly allocated in a double-blinded fashion into three groups . The control group ( Group 1 ) received normal saline 20 mL intraarticularly . The patients in the second and third groups received intraarticular morphine sulphate 1 and 5 mg in saline 20 mL , respectively . Post-operative pain was assessed on the 1st , 6th and 24th hour by visual analogue scale ( VSA ) . Supplementary analgesic requirement and possible complications were also followed . The intensity of pain and analgesic requirement were reduced more in the morphine 5 mg group than in the control group . It is concluded , that the administration of intraarticular morphine 5 mg provides long-lasting and effective analgesia after knee arthroscopy The purpose of this study was to determine whether morphine would be as effective as bupivacaine for postoperative  pain control  after knee arthroscopy with no worsening of the side effect profile . Eighty-two patients who underwent partial meniscectomy , chondral debridement , or both were prospect ively r and omized to receive 10 mg of morphine ( 10-cc volume ) or 10 cc of .5 % bupivacaine immediately postoperatively . Visual analog scale scores and side effect profiles were recorded in the postanesthesia care unit , in the transitional care unit , and then every 4 hours postoperatively until 24 hours . In-hospital data were available for all 82 patients , but postdischarge data were available for only 64 patients .  Visual analog scale scores in the postanesthesia care unit decreased from 3.4 on admission to 2.4 on discharge for the morphine group and from 2.6 to 2.4 for the bupivacaine group ( P>.217 , all time points ) . Medication use was the same for both groups in the hospital ( 62 % and 78 % , respectively ) with no statistical difference . Visual analog scale scores decreased from 3.0 to 1.5 for the morphine group and from 2.8 to 1.8 for the bupivacaine group between 4 and 24 hours postoperatively ( P>.376 , all time points ) . Medication use decreased between 4 and 24 hours postoperatively for both groups , from 71.7 % to 52.9 % , respectively , with no statistical difference at all time points . Four patients in the morphine group and 1 patient in the bupivacaine group experienced side effects . This study indicates that 10 mg of intra-articular morphine is as effective as 10 cc of .5 % bupivacaine for postoperative pain control for partial meniscectomy and chondral debridement of the knee . It minimally increases side effects initially and circumvents the issue of chondral toxicity of bupivacaine This study sought to compare the effects of morphine , bupivacaine , and saline injected into the knee after ar throscopic surgery . In a double-blind , r and omized trial , 124 patients received either bupivacaine , morphine , bupivacaine and morphine , or saline at the completion of surgery .  Postoperative pain was assessed with a 100-mm visual analog pain scale . Analgesic require ments were calculated , and weightbearing status was recorded . We found that morphine alone injected in traarticularly at the completion of arthroscopic knee sur gery had no significant effect on postoperative pain , need for supplemental analgesia , or weightbearing sta tus . Patients receiving morphine in combination with bupivacaine did not demonstrate any statistically sig nificant improvement over those receiving bupivacaine alone . Therefore , our results failed to show any ben eficial effect of morphine used for postoperative anal gesia , either alone or in combination with bupivacaine . The overall pattern in all patients demonstrated de creased pain scores , decreased analgesic use , and in creased weightbearing status as the observation period progressed . Finally , preoperative pain was correlated with pain at discharge , indicating that the most signifi ca nt predictor of postoperative pain was preoperative level of discomfort Background : Opioids produce antinociceptive effect by acting on receptors on peripheral nerves . The clinical relevance of this effect is still debated . The aim of the study was to compare the analgesic effect of morphine intraarticularly with the intramuscular route of administration after knee surgery This study compared the analgesic effect of intra-articular injection of tenoxicam with that of morphine on  postoperative pain after anterior cruciate ligament ( ACL ) reconstruction . Forty-two patients undergoing arthroscopically ACL reconstructions using hamstring tendons underwent the same anesthetic protocol . The patients were r and omized to receive 25 ml normal saline , 20 mg tenoxicam in 25 ml normal saline , or 2 mg morphine in 25 ml normal saline .  Postoperative pain was assessed using a visual analogue scale and measuring analgesic requirements . We found both that both intra-articular tenoxicam and intra-articular morphine provided better analgesia than that in the control group . Although pain scores were similar between tenoxicam and morphine groups  
    Output:
    
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 .