bupivacaine after arthroscopic knee surgery

10(1):104-107 Published by Raven Press, Ltd. © 1994ArthroscopyAssociationof North America

Arthroscopy: The Journal of Arthroscopic and Related Surgery

Analgesic Effect of Intraarticular Morphine, Bupivacaine, and Morphine/Bupivacaine After Arthroscopic Knee Surgery Barry P. Boden, M.D., Steven Fassler, B.A., Suzane Cooper, M.D., Paul A. Marchetto, M.D., and Raymond A. Moyer, M.D.

Summary: In a double-blind randomized fashion, 38 patients were divided into four groups according to the intraarticular injection received after arthroscopic surgery. Patients in group I (n = 7) received saline, group II (n = 10) morphine, group III bupivacaine, and group IV (n = 11) morphine and bupivacaine. Before surgery and at 0.5, 1, 1.5, 2, 6, and 24 h postoperatively, pain levels were recorded. In addition, postoperative supplemental i.v. morphine requested by the patient was tabulated. Results showed that the mean consumption of supplemental analgesia was lowest in the morphine/bupivacaine group. Although there was a statistically significant difference in pain scores between the Saline group and the other three groups during the early postoperative period, there was no significant difference in pain scores between the morphine, bupivacaine, and morphine/bupivacaine groups. We conclude that postoperative, intraarticular injection of analgesics is beneficial in reducing pain levels. The combination of morphine/bupivacaine appears to be the most beneficial analgesic due to its low supplemental analgesic requirements postoperatively. Key Words: Knee arthroscopy--Bupivacaine--Morphine.

MATERIALS AND METHODS

It is well recognized that opioid agonists have potent receptors in the central nervous system. Recently, it was d e m o n s t r a t e d that opioids also have peripheral receptors (1) that can provide analgesic effects in h u m a n s (2). Intraarticular injection of local anesthetics such as bupivacaine has b e e n studied extensively. Most of these reports indicate that intraarticular bupivacaine is an effective analgesic (3-8). The p u r p o s e of this study was to c o m p a r e the analgesic effects of intraarticular morphine, bupivacaine, and a morphine/bupivacaine combination.

The study was a p p r o v e d by the research review committee. I n f o r m e d consent was obtained before surgery. Criteria for exclusion from the study included cardiovascular, respiratory, or neurologic disease, a history of drug allergy, or the need for intraarticular drainage postoperatively. Thirty-eight patients w e r e enrolled in the study. Operative procedures included d e b r i d e m e n t , excision of loose bodies, m e n i s c e c t o m y , or meniscal repair. All patients received the following anesthetic regimen: 0.4 mg atropine, 3 mg d-tubocurare, 100-150 mg fentanyl, 0-2 mg m i d a z o l a m before induction, 5-6 mg/kg sodium pentothal, 100-120 mg succinylcholine for intubation, isoflurane, nitrous oxide/oxygen mix of 60/40, and 30 mg ketorolac prior to extubation. At the conclusion of surgery, after the arthroscopic portals w e r e closed, patients received one of four intraarticular injections in a double-blind ran-

From the Departments of Orthopedic Surgery (B.P.B.) and Anesthesiology (S.C.), Temple University Hospital; Temple University School of Medicine (S.F.); and Temple University Center for Sports Medicine (P.A.M., R.A.M.), Philadelpkia, Pennsylvania, U.S.A. Address correspondence and reprint requests to Dr. Barry P. Boden, Department of Orthopaedics, Temple University Hospital, Philadelphia, PA 19140, U.S.A. 104

ANALGESIS MORPHINE AND BUPIVACAINE

domized fashion. Injections in group I (n = 7) consisted of 20 ml saline, group II (n = 10) 1 mg morphine in 20 ml saline, group III (n = 10) 20 ml 0.5% bupivacaine with epinephrine (1/200,000), and group IV (n = 11) 1.0 mg morphine in 20 ml 0.5% bupivacaine with epinephrine (1/200,000). The solutions were chosen on a randomized basis without informing the surgeon or the assistant who recorded the pain levels. Pain assessment (9-11) was evaluated preoperatively in the short procedure unit, postoperatively at 0.5, 1, 1.5, and 2 h in the postanesthesia care unit (PACU), and at 6 and 24 h at home. The preoperative pain scores were subtracted from the postoperative scores. The visual analogue scale (VAS) score ranged from no pain (0 mm) to unbearable pain (100 mm). The pain rating index (PRI) assessed pain as none (0 points), mild (10 points), discomforting (20 points), distressing (30 points), horrible (40 points), excruciating (50 points), or in between any of these descriptive terms. In order to maintain patient comfort, postoperative orders in the PACU included supplemental analgesia consisting of only i.v. morphine given at a rate of 1 mg every 10 min upon request. Demographic data, pain scores, and the mean supplemental analgesia requested for each group are recorded as means + SEM. The VAS was measured as the score from no pain (0 mm) to the point marked by the patient. Analysis of variance was performed using the Newman-Keuls test. RESULTS There were no statistically significant differences in the age, weight, height, tourniquet time, and duration of surgery (Table 1) for the four groups. Most of the patients reported minimal preoperative pain levels. No meniscal repairs were performed in the saline group, one in the bupivacaine group, and two in both the morphine and the morphine/bupivacaine groups. Tourniquet times were not significantly dif-

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ferent in the four groups, although the average tourniquet time in the morphine/bupivacaine group was slightly longer. VAS scores (Fig. 1) were all significantly lower for the three medicated groups as compared with the saline group during the first 2 h postoperatively. There was no significant difference between the analgesic groups during this time period. At the 6- and 24-h postoperative periods there was no significant difference between the four groups, although there was a tendency for group IV to have slightly less pain at 6 h. The PRI scores (Fig. 2) showed a less prolonged effect of the analgesic agents. The three analgesic groups were in significantly less pain at 30 and 60 min, with no significant difference between groups I, II, and III. At 90 min, 2 h, and 6 h, there was no significant difference between the four groups. At 24 h the bupivacaine group reported more pain than did the other three groups. Total supplemental i.v. morphine requested in the PACU (Fig. 3) was lowest for the morphine/ 50[

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Arthroscopy, Vol. 10, No. 1, 1994

106

B. P. B O D E N E T A L .

bupivacaine group (0.88 mg) followed by the bupivacaine group (1.9 mg), morphine group (2.7 mg), and saline group (5.0 rag). The amount of supplemental analgesia requested by the patients receiving the morphine/bupivacaine injection was statistically lower (p < 0.1) than that requested by the saline group. The amount of supplemental analgesia requested by the bupivacaine group was statistically lower (to a lesser degree) than that requested by the saline group (p < 0.5). There were no side effects related to the intraarticular injections. DISCUSSION Due to the increasing cost of hospitalization, there has been a trend toward more outpatient surgery. In order to safely perform outpatient surgery, it is important to avoid the potential adverse systemic reactions of i.v. narcotics, such as respiratory depression, bradycardia, sedation, nausea, and vomiting. The use of locally acting analgesics has increased in popularity because they function with less risk of systemic side effects. Our results are consistent with other reports (2,4,6,12-14), which state that intraarticular bupivacaine with epinephrine can significantly reduce supplemental analgesic requirements or reduce pain scores. Nole et al. (15) showed that bupivacaine in

doses <0.5% has no deleterious effects on articular cartilage. Wasudev et al. (16) reported that plasma levels of bupivacaine after intraarticular injection are well below toxic levels if significant synovial surgery has not been performed. Systemic levels of intraarticular bupivacaine are lower when epinephrine is added to the solution (17). Gerber et al. (18) showed that plasma levels of 0.75% bupivacaine after intraarticular injection resulted in higher serum levels of bupivacaine than did solutions of 0.5% and 0.25%. Therefore, bupivacaine with epinephrine at concentrations of 0.5% are recommended for intraarticular injection. Our findings concur with other reports (2,6,13) that intraarticular morphine can produce antinocioceptive effects. The analgesic effect in our patients occurred earlier in the postoperative period. The prolonged effect of morphine was difficult to determine in this study because none of the four groups reported significant pain at 6 or 24 h. This may be due to the differences in the intraoperative anesthetic regimen, such as the addition of ketorolac, or the surgical procedures. Stein et al. (2) found that the same dose of intraarticular morphine provided a more pronounced postoperative analgesia than did the same dose of i.v. morphine, suggesting that the effect is mediated by local opioid receptors. Our results support this

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Arthroscopy, Vol. 10, No. I, t994

morphineand bupivacaine

ANALGESIS MORPHINE AND BUPIVACAINE

theory because the postoperative pain levels were significantly lower in the intraarticular morphine group compared with the saline control. These lower pain scores were reported despite a lower combined supplemental and intraarticular morphine dose than the total supplemental morphine in the control group. To our knowledge, no study has measured the plasma morphine concentrations to ensure that the joint was the site of action and not a depot for delayed absorption. Whether the effect of morphine is truly occurring locally will not be known until the peripheral mechanism of action is elucidated. Before the onset of this study, there had been no reports comparing bupivacaine with morphine or a bupivacaine/morphine combination. Recently in the anesthesia literature two reports have addressed this question. The results of Heard et al. (9) are difficult to interpret because they combined patients receiving general anesthesia with those receiving a regional anesthetic. Khoury et al. (10) found that intraarticular bupivacaine and morphine provided postoperative analgesia. Bupivacaine provided earlier (1-4 h) pain relief, and morphine was more effective on a delayed basis (4 h to 2 days). Combining morphine with bupivacaine provided analgesia throughout their 2-day observation period. Our results are similar to those of Khoury et al. (10), except that all four of our groups had minimal to no pain at 6 and 24 h, making it difficult to determine if morphine has a prolonged effect. Although the pain scores in the isolated bupivacaine and morphine groups were not statistically different during the first few hours postoperatively, the bupivacaine group required slightly less supplemental analgesia. This may indicate an earlier onset of action or a stronger potency of bupivacaine. The prolonged analgesic effect in the study by Khoury et al. is questioned because the arthroscopic portals were not closed before the injection of the analgesics, which usually leads to leakage of the medication. The pain scores in the bupivacaine/morphine combination group were not statistically different from the scores of the isolated bupivacaine and morphine groups. However, when both analgesics were injected, the supplemental morphine requested in the PACU was significantly decreased. The pain scores might have been lower for the combined group if supplemental analgesics were withheld, but this was felt to be unethical. The amount of narcotics requested may more accurately assess pain levels than would pain scales and are an important determinant in the timing of discharge.

107

CONCLUSIONS In summary we found that intraarticular injection of bupivacaine, morphine, or bupivacaine/morphine all reduce pain levels postoperatively in patients after arthroscopic surgery. The bupivacaine/morphine solution appears to be the most beneficial due to its low supplemental analgesic requirements postoperatively. REFERENCES 1. Joris J, Dubner R, Hargreaves K. Opioid analgesia at peripheral sites: a target for opioids released during stress and inflammation. Anesth Analg 1987;66:1277-81. 2. Stein C, Comisel K, Haimerl E, et al. Analgesic effect of intraarticular morphine after arthroscopic knee surgery. N Engl J Med 1991;325:1123--6. 3. Broadman L, Hannallah R, DeLeon E, Reff R. Intraarticular bupivacaine does not decrease narcotic requirements after arthroscopic surgery in adolescents. Can J Anaesth 1990;37 (suppl):51. 4. Chirwa S, MacLeod B, Day B. lntraarticular bupivacaine (Marcaine) after arthroscopic meniscectomy: a randomized double-blind controlled study. Arthroscopy 1989;5:33-5. 5. Henderson RC, Campion ER, DeMasi RA, Taft TN. Postarthroscopy analgesia with bupivacaine. Am J Sports Med 1990;18:614-7. 6. Kaeding C, Hill J, Katz J, Benson L. Bupivacaine use after knee arthroscopy: pharmacokinetics and pain control study. Arthroscopy 1990;6:33-9. 7. Meinig RP, Holtgrewe JL, Wiedel JD, Christie DB, Kestin KJ. Plasma bupivacaine levels foJlowing single dose intraarticular instillation for arthroscopy. A m J Sports Med 1988; 16:295-300. 8. Milligan K, Mowbray L, Mulrooney L, Standen P. Intraarticular bupivacaine for pain relief after arthroscopic surgery of the knee joint in daycase patients. Anaesthesia 1988;43:563--4. 9. Chapman C, Casey K, Dubner R, Foley K, Gracely R, Reading A. Pain measurement: an overview. Pain 1985;22:1-31. 10. Huskisson EC. Measurement ofp~Jn. JRheumato11982;9:768-9. 11. Stubbs DF. Visual analogue scales. Br J Clin Pharmacol 1979;7:124. 12. Smith I, Van Hemilrijck J, White P, Shively R. Effects of local anesthesia on recovery after outpatient arthroscopy. Anesth Analg 1991;73:536-9. 13. Khoury GF, Chen ACN, Garland DE, Stein C. Intraarticular morphine, bupivacaine, and morphine/bupivacaine for pain control after knee v i d e o a r t h r o s c o p y . A n e s t h e s i o l o g y 1992;77:263~5. 14. Heard SO, Edwards WT, Ferrare D, et al. Analgesic effect of intraarticular bupivacaine or morphine after arthroscopic knee surgery: a randomized prospective, double-blind study. Anesth Analg 1992;74:822~5. 15. Nole R, Munson M, Fulkerson J. Bupivacaine and saline effects on articular cartilage. Arthroscopy 1985;1:123-7. 16. Wasudev G, Smith BE, Limbird TJ. Blood levels of bupivacaine after arthroscopy of the knee joint. Arthroscopy 1990; 6:40-2. 17. Butterworth J, Carnes R, Samuel D, Janeway D, Poehling G. Effect of adrenaline on plasma concentrations of bupivacaine following intraarticular injection of bupivacaine for knee arthroscopy. Br J Anaesth 1990;65:537-9. 18. Gerber H, Censier K, Gachter A. Intra-articular absorption of bupivacaine during arthroscopy: comparison of 0.25%, 0.5%, and 0.75% solution [Abstract]. Anesthesiology 1985; 63A:217. Arthroseopy, Vol. 10, No. 1, 1994