More than 230 million surgical operations are been realized all over the world every year. A surgical intervention can cause postoperative acute pain. The management of postoperative acute pain is multimodal and the use of patient-controlled analgesia (PCA) is often a part of this Pain-Management.

Intravenous PCA has established itself as a therapeutic concept and constitutes the reference treatment for the management of postoperative acute pain for the first 48 hours. The PCA offers patients autonomy in managing their pain with the intravenous delivery of morphine on demand.

Since 2017 PCA Zalviso is marketed. It allows the sublingual administration of sufentanil and it does not require venous access. It seems interesting to allow the early rehabilitation of patients who are no longer limited in their movements by an infusion. However, its acquisition cost appears to be higher than that of the intravenous PCA. In order to verify this hypothesis, the investigators propose to compare the set of costs associated with the use of sublingual PCA with those of intravenous PCA in the management of acute postoperative pain (less than 72 hours) in the context of patients benefiting from the placement of a total knee arthroplasty.

Inclusion Criteria:

• adults
• patients able to express consent
• signed written informed consent form
• patient covered by national health insurance
• patient undergoing total knee arthroplasty and requiring postoperative analgesia with the use of a PCA (patient controlled analgesia)

Exclusion Criteria:

• minors
• obstruction to participate
• patient non covered by national health insurance
• patient requiring a stay in intensive care immediately after the surgery
• patient unable to use a PCA a assessed by the investigator