the studies had different primary end points: pain
score at rest or with movement (11 studies),
opioid reduction (5 studies), need for rescue analgesic
(3 studies), pain relief on a 5-point categorical
scale (2 studies), or difference between mean
pain scores (1 study). Also, duration of follow-up
ranged from less than 1 hour to 3 days, with
median of 1 day.