3.

Forest plot of 22 trials comparing the effects of any type of opioids and control (placebo or no intervention) on knee or hip pain. Values on x‐axis denote standardised mean differences. The plot is stratified according to type of opioids. Matsumoto 2005, Hartrick 2009, Afilalo 2010, Etropolski 2011, and NCT00486811 contributed with two comparisons and the standard error was inflated and the number of participants in the placebo group was halved to avoid duplicate counting of participants when including both comparisons in the overall meta‐analysis. Data relating to the 3, 3, 3, 2, 2, and 2 active intervention arms in Caldwell 2002, Chindalore 2005, Kivitz 2006, Matsumoto 2005, Hartrick 2009, and Etropolski 2011, respectively, were pooled.