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ANALGESIA

Intraarticular Administration of Ketorolac, Morphine, and Ropivacaine Combined with Intraarticular Patient-Controlled Regional Analgesia for Pain Relief After Shoulder Surgery: A Randomized, Double-Blind Study

From the Division of Anesthesiology and Intensive Care and Division of Orthopedics, Department of Medicine, Örebro University Hospital, Örebro, Sweden.

Address correspondence and reprint requests to Kjell Axelsson, MD, PhD, Department of Anesthesiology, Örebro University Hospital, Örebro, Sweden. Address e-mail to kjell.axelsson{at}orebroll.se.

Abstract

BACKGROUND: In this study we assessed the efficacy of intraarticular regional analgesia on postoperative pain and analgesic requirements.

METHODS: Fifty-one patients undergoing shoulder surgery (Bankart) were recruited into this double-blind study. At the end of the operation, patients were randomized to three groups to receive intraarticularly via a catheter: Group 1: ropivacaine 90 mg (9 mL), morphine 4 mg (10 mL), and ketorolac 30 mg (1 mL) (total volume 20 mL); Groups 2 and 3: saline (20 mL). In addition, Groups 1 and 3 received 1 mL saline IV while Group 2 received ketorolac 30 mg (1 mL) IV. Postoperatively, Group 1 received pain relief using 10 mL 0.5% ropivacaine on demand via the intraarticular catheter while Groups 2 and 3 received 10 mL of saline intraarticularly. Group 3 was the Control group.

RESULTS: Postoperative pain at rest and on movement were lower in Group 1 than in Groups 2 and 3 during the first 30 and 120 min, respectively. The time to first request for local anesthetic infusion was longer in Group 1 than in Groups 2 and 3 (P < 0.001). The median morphine consumption during the first 24 postoperative hours was less in Groups 1 and 2 than in Group 3 (P < 0.001). There was no significant difference in analgesic consumption between Group 1 and Group 2. The median satisfaction score was higher in Group 1 compared with Groups 2 (P < 0.05) and 3 (P < 0.001).

CONCLUSIONS: A combination of intraarticular ropivacaine, morphine, and ketorolac followed by intermittent injections of ropivacaine as needed provided better pain relief, less morphine consumption, and improved patient satisfaction compared with the control group. The group that received IV ketorolac consumed less morphine and was more satisfied with treatment than patients in the control group.

Good postoperative pain relief is one of the fundamental requirements after surgery and was endorsed by the Joint Commission on Accreditation of Healthcare Organizations as a human right.1 Pain after major shoulder joint surgery is often very severe2 and its satisfactory management continues to be a challenge after ambulatory surgery. Adequate pain relief is essential, both for the patient’s well being as well as to facilitate recovery.3

The interest in wound infiltration and intraarticular analgesic techniques has increased, since these are simple to perform and associated with improved analgesia, reduced opioid use, and increased patient satisfaction.4 However, intraarticular local anesthetic (LA) as a single injection has only a mild analgesic effect of short duration5 while continuous or patient-controlled administration of LA via catheters and infusion pumps is more effective and can prolong the duration of analgesia.6–8 Ketorolac, a nonsteroidal antiinflammatory drug, provides satisfactory analgesia after both systemic9 and intraarticular administration.10–12

To produce optimal systemic analgesia combined with the lowest incidence of side effects, a multimodal pain therapy is essential.13 Intermittent self-administration of LA into the operating field via a catheter and an elastomeric balloon pump has been reported to be effective for the management of postoperative pain.7,8 The primary aim of the present study was to evaluate postoperative morphine consumption after intraarticular injection of a mixture of ketorolac, morphine, and ropivacaine intraoperatively combined with a patient-controlled regional analgesia (PCRA) technique using ropivacaine and ketorolac or placebo (saline) IV after major shoulder surgery (Bankart). Pain intensity, safety, side effects, and quality of life during the first 7 postoperative days were also measured as secondary end points.

METHODS

After approval of the Local Ethics Committee and written informed consent, we studied 51 patients (ASA I–II), 18–65 yr undergoing major open or arthroscopic Bankart surgery due to shoulder dislocation. Patients were excluded if they had chronic pain, contraindications to the use of nonsteroidal antiinflammatory drugs, or had difficulty in understanding the pump function due to language and other barriers. All patients were given oral paracetamol 1 g 4 times a day with the first dose given 30–60 min before induction of general anesthesia. The patients were anesthetized according to a standardized protocol consisting of propofol 2 mg/kg IV, fentanyl 1–2 µg/kg IV, rocuronium 0.6 mg/kg, and O₂ (Fio₂ 0.33) in N₂O and isoflurane. After endotracheal intubation, the patients were placed in the beach chair position. At the end of the operation, the surgeon placed a 20 G multiorifice catheter through an 18 G epidural needle (B-Braun, Mellsungen, Germany), all orifices were placed intraarticularly. The catheter was tunneled 4–5 cm subcutaneously and secured on the skin with a transparent adhesive dressing (Tegaderm®) and tape. No surgical drain was used in any patient.

The patients were randomized into three groups of 17 in each group using a computer-generated randomization list. In Group 1, the patients received 30 mg (1 mL) ketorolac, 4 mg (10 mL) morphine, and 90 mg (9 mL) 1% ropivacaine intraarticularly via the catheter (total volume 20 mL) and 1 mL saline IV, 10 min before the end of the operation. In Group 2, 20 mL saline was infused intraarticularly and 30 mg (1 mL) ketorolac was given IV. In Group 3, 20 mL of saline was injected intraarticularly and 1 mL saline IV and served as a control group. The operating nurse connected an elastometric pump (Home pump®) containing 100 mL of either 0.5% ropivacaine (Group 1) or saline (Groups 2 and 3) to the intraarticular catheter under aseptic conditions. Both the orthopedic surgeon and the attending anesthesiologist (investigator) were blinded to the drug assignment. All measurements were made and recorded by another investigator who also was blinded to the study drug. When the patients had moderate-severe pain postoperatively (visual analog scale [VAS] >3), they were asked to use the Home pump® for the self-injection of 10 mL of LA or saline by opening a clamp for a fixed time of 6 min.11 If the pain relief was unsatisfactory 20 min after the start of the infusion (VAS 5), 1–2 mg morphine was administered IV every 5 min and, when VAS was <5, 100 mg dextropropoxyphene (maximum 400 mg/d). The patients could self-administer 10 bolus doses using this system under the supervision of a nurse. The patient was instructed to avoid using the Home pump® more than once every hour. The investigator gave oral as well as written instructions as to the correct management of this system, both before the start of the operation and during the postoperative period.

After the 24-h study period, the investigator removed the catheter, the tip of the catheter was sent for culture and before the Home pump® was discarded, the residual volume was measured. Pain intensity was estimated by a VAS (0–10 cm; 0 = no pain, 10 = worst imaginable pain) at rest and on active mobilization, which was done by asking the patients to sit and move the arm 30° in a pendulum-like movement antero-posteriorly. The patients were supervised in the postanesthesia care unit during the 24-h test period. The time to first analgesic request via the Home pump® was recorded. The difference in pain score before and 20 min after starting local administration of the solution was calculated. Morphine and oral analgesic consumption, nausea, and vomiting were registered during the first 24 h. Patient’s satisfaction during the first 24 postoperative hours was rated according to a satisfactions score: 1 = poor, 2 = satisfactory, 3 = good, and 4 = excellent. After discharge, the patients were asked to complete a questionnaire regarding postoperative pain and Activities of Daily Living (ADL) at Days 1, 2, 3, and 7. This questionnaire included aspects of pain, sleep disturbances due to pain, appetite, difficulty in concentration, nausea and vomiting, the ability to dress without help, and to return to work. Paracetamol 1 g was given every 6 h to all patients. If pain relief was inadequate (VAS 4), dextroproxyphene 50 mg was administered as rescue medication when required, to a maximum dose of 400 mg/d.

The mean (±sd) morphine consumption during 24 h after shoulder surgery was found to be approximately 20 mg (±10 mg) from the pilot patients we studied previously. We wanted to reduce this by 50% to 10 mg (±5 mg) after the use of a multimodal pain management technique with a combination of ketorolac, morphine, and ropivacaine. Using t-test and assuming unequal variances, a power of 90% to detect a difference and an level of 5%, 15 patients/group should be required. To compensate for possible dropouts we recruited 17 patients/group. Pain data, both at rest and movement, were analyzed using the repeated measurements analysis of variance. Study group was treated as a between-subject factor and time was treated as a within-subject factor. Post hoc analyses were done with Tukey adjustment or Bonferroni Holm correction where appropriate for multiple comparisons. For each patient, a median VAS value for all self-administration of study drug was calculated. Subsequently, a median value for each group was calculated before and after the infusion. A statistical analysis using the Mann–Whitney U-test was then used followed by the Bonferroni Holm correction for multiple groups. Finally the pre- versus postinfusion values were calculated using the Wilxon’s paired test. The computation was performed as a mixed model and implemented in SAS version 8.1 (SAS Institute Inc., Cary, NC). Morphine consumption, time to first request of LA infusion and satisfaction scores were analyzed using the Kruskal–Wallis test for overall effect followed by the Mann–Whitney U-test and Bonferroni-Holm correction for pairwise group analyses.14 The Fisher’s exact test followed by the Bonferroni correction was used to analyze dichotomous variables. A P value <0.05 was considered significant.

RESULTS

One patient in Group 1 was excluded due to an unpleasant numbness of the fingers after infusion of the test dose (probably due to leakage of LA into the axillary plexus at the time of its administration). Thus, 16 patients in Group 1 and 17 patients in Groups 2 and 3 were evaluated. There were no statistical differences in the demographic and surgical data among groups (Table 1). The median morphine consumption during the first 24 postoperative hours was significantly lower in Groups 1 and 2 than in Group 3 (P < 0.001). Moreover, the number of patients who required morphine was significantly lower in Groups 1 and 2 than in Group 3 (P < 0.001 and P = 0.007, respectively) (Table 2). There was no significant difference in dextropropoxyphene consumption among the groups during the first 7 postoperative days.

The postoperative VAS pain at rest and movement was significantly lower in Group 1 than in Group 2 during the first 30 min (P < 0.001) (Figs. 1 and 2). The VAS pain score at rest was significantly lower in Group 1 than in Group 3 at 30, 60, and 120 min (P < 0.001). The mean value of VAS at rest in Group 1 was 2 during the 24-h test period, but not in Groups 2 and 3, specifically during the early postoperative period. The mean value of VAS at movement in Group 1 was 2 during the 18-h test period, but not in Groups 2 and 3, where the pain intensity was 5 and 6 or lower, respectively.

View larger version (15K): [in this window] [in a new window]   Figure 1. Postoperative pain at rest. Visual Analog Scale (VAS) scores (mean ± sd) were evaluated in hospital during the period 0–24 h and at home using a questionnaire on Days 1–7. Group 1 = 30 mg ketorolac, 4 mg morphine, and 90 mg ropivacaine (intraarticularly) + Patient Controlled Regional Analgesia (PCRA) ropivacaine (intraarticularly) + saline IV. Group 2 = saline (intraarticularly) + PCRA saline (intraarticularly) + 30 mg ketorolac IV. Group 3 = saline (intraarticularly) + PCRA saline (intraarticularly) + saline IV. *Significant difference between Group 3 versus Group 1; Significant difference between Group 2 versus Group 1.

View larger version (16K): [in this window] [in a new window]   Figure 2. Postoperative pain Visual Analog Scale (VAS) on movement. VAS-scores (mean ± sd) were evaluated in hospital during the period 0–24 h and at home using a questionnaire on Days 1–7. Group 1 = 30 mg ketorolac, 4 mg morphine, and 90 mg ropivacaine (intraarticularly) + Patient Controlled Regional Analgesia (PCRA) ropivacaine (intraarticularly) + saline IV. Group 2 = saline (intraarticularly) + PCRA saline (intraarticularly) + 30 mg ketorolac IV. Group 3 = saline (intraarticularly) + PCRA saline (intraarticularly) + saline IV. *Significant difference between Group 3 versus Group 1; Significant difference between Group 2 versus Group 1.

In Group 1, 14 patients rated the pain relief as good or excellent during the first 24 h postoperatively. In Groups 2 and 3, the corresponding figures were 10 and 4 patients, respectively. There was a significant difference between Groups 1 and 3 (P < 0.001). The median (range) satisfaction score was significantly higher in Group 1: 4 (2–4) compared with Group 2: 3 (1–4) (P < 0.05) and Group 3: 2 (1–3) (P < 0.001). Patients in Group 2 were significantly more satisfied than those in Group 3 (P < 0.05). The frequency of vomiting in Groups 1 and 3 was 0 vs 5 patients (P > 0.05). There was no significant difference among the groups in nausea or pruritus.

There was a positive catheter tip culture with a higher density of growth of coagulase negative staphylococcus in one patient in Group 1. There were no clinical symptoms or laboratory evidence of infection in this patient. However, antibiotic treatment with flucloxacillin 1 g 3 times a day was administered for 5 days as a precaution. In four patients only isolated bacterial cultures of Staphylococcus aureus (one patient in Group 2 and two patients in Group 3) or of anaerobic diphtheroid bacilli (one patient in Group 2) were found. Clinically, these four patients had no antibiotic treatment and they had no symptoms or signs of infection on follow-up. The ADL questionnaire revealed that the patients frequently woke-up at night (31%–50%) and had difficulties in dressing due to pain (25%–27%) on Day 7. In addition, 25% to 35% of the patients were willing to return to work on Day 7. There were, however, no significant differences among the groups.

DISCUSSION

In this randomized, double-blind study, we found that a multimodal technique using a combination of ropivacaine, morphine, and ketorolac intraarticularly at the end of the operation, and patient-controlled ropivacaine significantly decreased morphine consumption, pain intensity for 24 h and delayed time to first analgesic request via the elastometric pump resulting in increased patient satisfaction compared with IV saline followed by patient-controlled injection of saline. Compared with the IV ketorolac group, we found that the combination group had prolonged time to first request of analgesia, decreased initial pain intensity, and satisfaction with pain control.

Intraarticular Ropivacaine, Morphine, and Ketorolac
The intraarticular technique offers advantages in its simplicity and minimal risk for complications. Multimodal pain management also ensures good analgesia and increased patient satisfaction. The effects of intraarticular ketorolac and bupivacaine after artroscopic knee surgery were evaluated by Reuben and Connelly.15 They found that this combination provided higher quality and longer duration of pain relief than each drug alone. Similarly, Gupta et al.10 reported that a combination of morphine and ketorolac produced a synergestic analgesic effect after arthroscopic knee surgery. Ng et al.16 compared analgesic efficacy of a combination of ropivacaine, morphine, and ketolorac to ropivacaine alone administered intraarticularly and found that morphine and ketolorac enhanced analgesia produced by LA alone up to 24 h, reduced postdischarge analgesic consumption, and improved ADL without increasing side effects after ambulatory arthroscopic knee surgery. Finally, the combination of a ropivacaine, ketorolac, and morphine has been reported to be superior to saline or the combination of ropivacaine and morphine after other painful orthopedic procedures such as anterior cruciate ligament reconstruction.17 Thus, our findings in the present study after shoulder surgery confirm those of others after knee surgery.

PCRA
A single dose of LA administered intraarticularly is reported to provide a short duration (4 h) of analgesia.5 If higher doses of ropivacaine (500 mg) are administered subacromially, the duration of analgesia may be increased to 5–6 h without any major risk of toxicity.8 However, further prolongation of analgesia requires the continuous or intermittent delivery of analgesics at the site of surgery. We achieved this using the PCRA technique and intermittent, patient-demanded injection of intraarticular ropivacaine. Twenty minutes after intraarticular LA infusion, the pain scores were significantly decreased when LA was administered (Group 1), which was similar to our previous findings where we found that pain could be reduced by about 40% at rest and 20% on movement using this technique.8

The morphine consumption in patients receiving multimodal analgesia was significantly lower than for those who received saline intraarticularly. Unfortunately, lower morphine consumption did not translate into lower incidence of side effects such as postoperative nausea and vomiting.

Postoperative Outcomes
We found that patients receiving the combination of drugs and LA via the Home pump® were more satisfied than those receiving saline up to 24 h postoperatively. However, after 24 h other indicators of quality and ADL did not differ among the groups. This may be because the study was not powered to detect these differences or that rehabilitation after upper extremity surgery is less dependent on adequate pain relief as it would be after lower extremity surgery. Indeed, in an earlier study of patients undergoing less traumatic surgery (knee arthroscopy), the authors found that patients who had received an intraarticular combination of LA, morphine and ketorolac had fewer sleep disturbances during the first 1–2 days, and more patients were willing to return to work during the first 2 days after the operation.16 However, in the present study, sleep disturbances continue to be a problem after 7 days, 35% to 50% of the patients still had difficulty sleeping due to pain, without any significant differences among the groups.

Side Effects
All patients were discharged after 24 h without any complications. No major side effects were reported on the 7-day follow-up questionnaire. We did not observe any evidence of increased inflammation or pain in our patients receiving intraarticular ketorolac between the 4th and 7th postoperative day as assessed by the questionnaire. There is a risk of infection (5%–12%) when drains are used.18 In the present study, four catheter tips had isolated bacterial cultures and the fifth had a higher density of coagulase negative staphylococcous without any clinical symptoms or laboratory evidence of infection.

Study Limitations
The incorporation of a placebo group in this study can be questioned. However, since there is limited documentation on the methods used for pain relief postoperatively after shoulder surgery,2,19 we felt that it would be important to include a placebo group in this trial. Another drawback of this study is that the IV ketorolac group did not receive morphine IV as did the group that received combination treatment with intraarticular morphine. Since it has been shown that intraarticular morphine may be absorbed into the systemic circulation, it may have been appropriate to inject a similar dose of morphine IV. Another question that remains unanswered is the role of combination treatment preoperatively for providing postoperative analgesia. Probably, and in hindsight, it may have been an advantage to administer only LA intraarticularly at the end of surgery in the group receiving ketorolac IV. This would have confirmed if the combination of ketorolac, morphine and ropivacaine intraarticularly is indeed better than LA intraarticularly combined with IV ketorolac. The catheter was removed after 24 h, as per protocol, but patients continued having moderate pain after 24 h and perhaps we should have had the catheter retained for up to 48 h to improve postoperative analgesia; future studies should take this into consideration. However, at the time of this study there were concerns about the risk of infection. Finally, a patient-controlled analgesia regimen with IV morphine as rescue medication may have been an advantage. This suggestion was discussed, but we felt that the patients could have been confused as to which technique to use, the PCRA or patient-controlled analgesia during the 24 h observation period and therefore the results may have been unreliable.

CONCLUSIONS

The combination of morphine, ketorolac, and ropivacaine intraarticularly at the end of the operation prolongs early postoperative pain relief and reduces analgesic requirements in the postanesthesia care unit. This approach, combined with intraarticular PCRA using an elastometric pump for delivery of LA, is effective and provides good patient satisfaction and seems to be somewhat more effective than IV ketorolac, but only during the initial postoperative period.

ACKNOWLEDGMENTS

We thank Anders Magnuson, Bio-statistician, Department of Clinical Medicine, University Hospital, Örebro for his help with statistical calculations.

Footnotes

Accepted for publication September 19, 2007.

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This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a colleague Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via Web of Science (3) Citing Articles via Google Scholar Google Scholar Articles by Axelsson, K. Articles by Nordensson, U. Search for Related Content PubMed PubMed Citation Articles by Axelsson, K. Articles by Nordensson, U. Related Collections Pain Medicine Regional Anesthesia Pharmacology