The main objective of this study is to show that postoperative Total Knee Replacement (TKR), an analgesic perineural catheter in position under sartorial (KTSS) best preserves motor quadriceps femoral perineural catheter that (KTF) infused with even low doses of local anesthetics, this motor being evaluated by a semi quantitative simple clinical test locking of the knee feasible at the bedside.

Patients will be randomized in two arms:

• catheter in position under sartorial (experimental group)
• femoral catheter (control group)

Inclusion Criteria:

• Major Patient (≥ 18 years)
• Before tricompartmental benefit from knee replacement (TKR) unilateral,
• TKR programmed on one of the first three days of the week (Monday to Wednesday)
• Physical status score I-III,
• Non septic programmed surgery under general anesthesia
• Able to understand the protocol
• Written informed consent
• Social Insured
• Opportunity to be followed under the Protocol

Exclusion Criteria:

• Age ≥ 85 years
• Obesity (BMI ≥ 35)
• Revision TKR,
• Patients not cooperating or not including the French,
• Difficulties in understanding and evaluating the score pain (VAS),
• Preoperative cognitive dysfunction making unreliable interrogation
• Patient unable to read and / or write (literacy, ...)
• Known bleeding disorders,
• Vascular surgery for femoral vessels on the operated side,
• Neuropathy of the lower limb,
• Localized infection at the puncture catheters,
• Known allergy to ropivacaine,
• Renal and / or severe hepatic impairment,
• Taking opioids for more than a month before surgery,
• Intolerance to morphine,
• Rheumatic inflammatory disease,
• Patients receiving immunosuppressive therapy or long-term corticosteroid
• Allergy or against-indications to standard treatments administered intraoperative and postoperative
• Flexion deformity> 10 ° or valgus deformity with significant
• Refused to participate
• Patient trusteeship, guardianship, deprived of liberty
• Women premenopausal who become pregnant