This meta-analysis identified 22 randomized controlled trials that compared the use of opioids to placebo or non-opioid analgesics with respect to the reduction of pain and improved function in patients with osteoarthritis. Of these studies, 18 were randomized placebo-controlled trials (the other 4 studies compared opioids to NSAID's or paracetamol, and did not provide enough robust data). Of the 18 studies with placebo as the comparator, a total of 4856 patients were identified (3244 opioids, 1612 placebo). The results from the analysis of these 18 studies indicated that the use opioids (strong opioids in particular) was more effective in relieving patient pain and improving function in comparison to placebo. However, it is important to note that opioid use resulted in the occurrence of several adverse events.