Over the last two decades, perioperative analgesia has evolved. Spinal and epidural anaesthesia, once common, have been gradually phased out due to their side effects. The femoral block combined with the sciatic block, possibly with a perineural catheter, is now the gold standard for ensuring prolonged, high-quality analgesia. However, these blocks can cause muscle weakness in the quadriceps, limiting patients' functional recovery.

To optimise functional rehabilitation, recent techniques favour more distal and selective blocks, such as the adductor canal (saphenous) block and the iPACK, which allow effective anaesthesia to be maintained whilst preserving motor function. However, these blocks do not always guarantee complete analgesia and may require additional blocks.

The hypothesis of the current study is based on the idea that a proximal block targeting the femoral, obturator and sciatic nerves, administered with a low concentration of naropeine (0.1%), could provide more effective analgesia than a 0.5% saphenous iPACK block, whilst preserving motor function The originality of our approach in the current study lies in the use of dissociative proximal blocks performed with low concentrations of local anaesthetics, aimed at effectively covering the innervation of the knee whilst preserving motor function.

The expected outcomes of this research are to optimise analgesic management for patients undergoing functional orthopaedic knee surgery, to promote early postoperative walking rehabilitation, to reduce the risk of chronic pain following knee arthroplasty, and to provide evidence to guide anaesthetic and post-surgical rehabilitation practices

Inclusion Criteria:

• Age > 18 years;
• Patients scheduled for total knee replacement (TKR);
• ASA (American Society of Anesthesiologists) class 1 to 3;
• Patient who is able to understand the information relating to the study, read the information leaflet and agree to sign the informed consent form;
• Enrolment iin the French healthcare system.

Exclusion Criteria:

• Patients with an ASA score > 3;
• Patients with a chronic pain condition requiring regular prescription pain relief, such as osteoarthritis, fibromyalgia, neuropathic pain or rheumatoid arthritis;
• Patients with a major anxiety disorder (APAIS score);
• Patients with a history of algodystrophy;
• Pregnant or breastfeeding women;
• History or evidence of any other clinically significant disorder, condition or disease which, in the investigator's opinion, would pose a risk to patient safety or interfere with the assessment, procedures or completion of the study;
• Participation in any other clinical trial during the duration of the study;
• Patients under guardianship or curatorship or subject to deprivation of liberty.