Continuous peripheral nerve blocks are considered as the gold standard for postoperative analgesia in orthopaedic surgery (shoulder, knee, foot). These techniques are also used in chronic pain.

The main disadvantage of these techniques is that they can drive a more or less deep motor block that slows down the rehabilitation process. This disadvantage could be prevented (or minimized) by adapting the protocol for administering local anesthetics or by changing molecules (levobupivacaine 0.625 mg/ml instead of ropivacaine 2 mg/ml). There is no literature comparing the effectiveness of the sensory block and its impact on the motor block according to the administration protocol and/or the type of local anesthetics.

The main judgement criterion of such a study could be a composite criterion crossing the quality of the sensory block and the depth of the motor blockades, the ideal being to have a perfect sensory block without any motor block.

Inclusion Criteria:

• >18 years old
• ASA score 1 to 4
• Scheduled orthopaedic surgery
• consent to participate

Exclusion Criteria:

• Pregnant, parturient, or breastfeeding woman
• Emergency situation
• Contraindications to local anaesthesia
• Patient refusal

All patients undergoing scheduled orthopedic surgery for which perinervous catheter analgesia is usually indicated (complex shoulder, elbow, femur, knee, foot surgery) will be included.