Twelve hours following a unilateral total knee replacement, a client reports being unable to sleep because of severe incisional pain. What is the best initial nursing action?

Instruct the client in use of the prescribed patient-controlled analgesia (PCA) pump.

Assist the client in assuming a lateral recumbent position for comfort.

Initiate continuous passive motion (CPM) to relieve muscle spasms.

Apply ice to the incision for twenty minutes prior to joint flexion exercises.