Patient-controlled analgesic (PCA) pumps work quite well to control pain without causing addiction. Although the patient controls how much drug is given, there is a lock-out mechanism. The pump is set to only give X number of milligrams of drug every X number
of minutes. If the patient hits the button over and over, nothing else is given until the next dose is due.
There's also a way to program the pump so that the patient never gets more than the maximum dosage allowed over time. If there's breakthrough pain while on the PCA, then additional painkillers can be given by mouth (orally).
Most patients use the PCA for the first 24-hours. Once they are up and moving again, postoperative pain is replaced by soreness and aching. Patients seem to be able to handle the sore, aching pain with over-the-counter analgesics like ibuprofen or tylenol.