No evidence for analgesic effect of intra-articular morphine after knee arthroscopy: A qualitative systematic review

There are few well-controlled RCTs on IA morphine, and the negative trials of higher quality counter the evidence from the numerous positive ones of lower quality. The quality of most published trials is poor, and performing meta-analysis on these data is not meaningful. Properly controlled trials, in which early postoperative pain intensity is documented, suggest that there is no added analgesic effect of IA morphine compared with saline alone.