Continuous adductor canal block (CACB) is becoming increasingly popular for providing postoperative analgesia following knee arthroplasties. These continuous blocks are provided through inserted nerve catheters and effectively extend the duration of analgesia, thereby reducing opioid consumption. This, in turn, helps minimize opioid-related side effects, promotes early ambulation, and supports earlier discharge. However, catheter migration remains a significant concern, as the catheter tip can become displaced from the adductor canal due to movements associated with ambulation or physiotherapy. In this study, the investigators compare the migration rates of two different techniques for CACB catheters insertion: the Interfascial plane between SArtorious muscle and FEmoral artery (ISAFE) and the Out Of Plane parallel to Saphenous nerve (OOPS) techniques. Pain scores and opioid consumption on postoperative day 1 (POD1) will also be assessed as secondary outcomes. The hypothesis is that both techniques will result in similar migration rates of CACB catheter.
Non-pregnant patients older than 18 years of age;
Patients undergoing unilateral primary total knee arthroplasty in an inpatient regime;
American Society of Anesthesiologist (ASA) physical status Class I - IV patients;
With sufficient understanding and co-operation about usage of a perineural catheter for pain management;
They have a failed spinal anesthesia and needs for a conversion to general anesthesia;
The peripheral nerve blocks are not possible to be performed due to technical difficulties;
A deviation of the protocol occurs (not follow the standardized postoperative analgesia orders; need an emergency re-operation of the same knee, in less than 24 hours, due to a surgical complication; have an important perioperative complication, leading to abnormal level of conscience);
CACB catheter has issues on its function and needs to be removed before the migration assessment