The search strategy identified 1,116 trials, of which 31 (1,760 total participants) met the inclusion criteria for this review. The trials took place in 20 countries, with publication dates extending from 1980 to 2016. The type of peripheral nerve block performed varied greatly in the studies, including type of nerve block (eg, femoral nerve block, fascia iliaca compartment block), duration of block (eg, singleshot block, continuous block), technique (eg, nerve stimulator, ultrasonographic guidance, landmark technique), and timing of nerve block (eg, preoperatively, intraoperatively, postoperatively).