Intra-articular buprenorphine after knee arthroscopy. A randomised, prospective, double-blind study.

Background: Demonstration of peripheral opioid receptors in inflamed synovia supports the concept of peripheral opioid analgesia. The aim of this study was to evaluate the analgesic effect of intra-articular administration of buprenorphine after knee arthroscopy.

Methods: In a double-blind randomised trial, 48 patients were assigned to four groups: group A patients received buprenorphine 100 micrograms i.a. and NaCl 0.9% i.m., group B patients received bupivacaine 0.25% 50 mg i.a. and NaCl 0.9% i.m., group C patients received NaCl 0.9% i.a. and buprenorphine 100 micrograms i.m., and group D patients received NaCl 0.9% i.a. and NaCl 0.9% i.m. Intensity of postoperative pain was evaluated by VAS at recovery (T0) and 1, 3, 6, 12, 24 h after operation (T1, T2, T3, T4, T5), at rest and during passive 10 degrees knee flexion. Total analgesic requirements and side effects related to study drugs were recorded.

Results: The VAS scores were significantly higher in groups C and D than in group A and B patients. The differences were significant at T0, T1, T2 and T3. At T1, group C and D patients had greater analgesic requirement than groups A and B. No patients developed side effects.

Conclusion: Intra-articular buprenorphine and i.a. bupivacaine, both produced equally good postoperative pain control and allowed a significant reduction of analgesic requirement after knee arthroscopy.