Comparison of intra-articular fentanyl and intra-articular bupivacaine for post-operative pain relief after knee arthroscopy

A randomized double-blinded study consisting of 107 patients was conducted to compare the effect on postoperative pain relief of intra-articular fentanyl and intra-articular bupivacaine after knee arthroscopy. The results showed that infra-articular bupivacaine produced superior analgesia in the immediate postoperative period. At 2 h post-operatively, the intra-articular bupivacaine group had a mean pain score of 2.0 (standard deviation 2.1, P < 0.05) compared with the intra-articular fentanyl group which had a mean pain score of 3.2 (standard deviation 2.3, P < 0.05). After 2 h post-operatively, intra-articular bupivacaine and intra-articular fentanyl had a similar effect on pain scores. The mean pain score 18 h post-operatively was 2.7 for the intra-articular bupivacaine group (standard deviation 2.2, P value 0.6) compared with the intra-articular fentanyl group which had a mean pain score of 2.8 (standard deviation 1.9, P value 0.6).