Six eligible studies were retrieved: five randomised controlled trials (RCTs) and one quasi-experimental study. A total of 592 patients were included.
No information was provided on the methods of allocation that were used. Investigators in three RCTs were clearly blinded and not blinded in one. Only the quasi-randomised trial provided details of the intervention used.
Knowledge about PCA (three RCTs and one quasi-experimental study; n=447):
All four studies reported significantly better knowledge about how to use the PCA device to improve pain relief, compared to patients in the control groups.
Pain control (four RCTs and one quasi-experimental study; n=506):
Only the quasi-experimental study showed statistically significantly better pain control (p<0.05; actual P-value not reported) in the intervention group, measured using a visual analogue scale. Pain scores at rest, positional change and rehabilitation were all reportedly significantly lower compared to the control group.