This randomized, double blind controlled trial is designed to investigate the potential benefits of radiofrequency in terms of analgesia and functional outcome, compared to the conventional continuous adductor canal block, for patients undergoing total knee arthroplasty for osteoarthritis.
The aim of this study is to compare the efficacy of two analgesia techniques in patients undergoing Total Knee Arthroplasty (TKA) on the functional recovery and pain control: Pulsed and Continuous Radiofrequency (PRF and TRF) applied respectively to the saphenous nerve and to the genicular nerves of the knee (femoral and sciatic branches) compared with Continuous adductor canal block with local anesthetics (CACB). The Null Hypothesis is that no difference exists in the functional recovery, in pain medication consumption and in postoperative exercise and physical performance between two groups of patients submitted to TKA with the two different modalities of analgesia. To test the null hypothesis we hypothesize as clinically relevant: * a reduction of 30% in the time needed to perform the Timed Up and Go test at 2 days after surgery * a reduction of 30% in pain medication consumption in the first 24 ore after surgery. To test the null Hypothesis, 40 patients are needed (20 for each group). The primary outcome measures will be: * the time required in the two groups (CACB-group and RF-group) to perform the Timed-Up and Go (TUG) test on the second postoperative day (POD2). TUG measures the time that a person takes to rise from a chair, walk three meters, turn around, walk back to the chair, and sit down. During the test, the person is expected to use any mobility aids that they would normally require. * the total morphine consumption by means of the patient-controlled analgesia pump over the first 24-h after surgery, which can be measured precisely through the record of the dose delivered by the PCA pump. With an alpha error of 0.05, a power of 80% and a standard deviation of 7 mg of morphine consumption per 24 h, 20 patients (10 in each group) will be required for the study to detect a mean difference of 10 mg of morphine between the two groups Secondary outcome measures include: Pain evaluation with the use of VAS at rest, VAS on walking and on knee flexion; functional outcome evaluation with the 6 min walk tests, degree of knee flexion, Scores obtained in self-assessment questionaire (WOMAC-Western Ontario and McMaster University questionaire for knee osteoarthritis and CHAMPS-Community Healthy Activities Model Program for Seniors). These values will be compared with baseline values recorded before surgery. It is hypothesized that PRF and TRF of the saphenous nerve and genicular nerves to the knee joint can improve the early and late functional recovery and the pain control after TKA when compared with the CACB
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
40
Preoperative pulsed radiofrequency of the saphenous nerve and Continuous radiofrequency of the genicular nerves of the knee joint. The saphenous nerve will be approached at the adductor canal and it will be treated with Pulsed RF for 4 minutes at 42 Celsius degrees. Ropivacaine 0.5% 10ml with Dexamethasone 10mg will be injected after the RF. The Genicular terminal branches of the sciatic and femoral nerves will be treated with Continuous RF for 3 min at 80 Celsius degrees and then with 2 ml of Ropivacaine 0.5% and 10 mg of Methylprednisolone to each nerve (5 in total) A sham catheter in the mid-thigh will be placed for patients in the RF group, infusing Normal Saline 0.9% and simulating a Continuous Adductor Canal Block. To blind the investigator to the type of treatment for the postoperative assessment , every solution bag will be prepared by the Pharmacy of the Hospital, covered with a plastic envelope and labeled as "Study Solution".
The patients in the Adductor canal group, will have a catheter for peripheral nerve block inserted under strict asepsis in the adductor canal under ultrasound guidance, and will receive for postoperative analgesia a 48-h continuous infusion of Ropivacaine 0.2% at 8 ml/hour The patients will receive, intraoperatively 10 mg of Dexamethasone i.v. To blind the investigator who will do the postoperative assessment to the type of treatment, every solution bag will be prepared by the Pharmacy of the Hospital, covered with a plastic envelope and labeled as "Study Solution". It will be always possible to crack the code and find out to which group the patient belongs
McGill University Health Centre, Montreal General Hospital
Montreal, Quebec, Canada
Postoperative morphine consumption
Time frame: first postoperative day (first 24 hours)
Timed-Up and Go Test
TUG measures the time that a person takes to rise from a chair, walk three meters, turn around, walk back to the chair, and sit down. During the test, the person is expected to use any mobility aids that they would normally require
Time frame: 2nd postoperative day
Six minutes walk test
This test measures the distance that a patient can quickly walk on a flat, hard surface in a period of 6 minutes
Time frame: 6 weeks after surgery
Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC)
The WOMAC consists of 24 items divided into 3 subscales: Pain (5 items);Stiffness (2 items); Physical Function (17 items). The Extent of pain, stiffness in the knee, and physical function related to the disability due to the knee osteoarthritis are assessed with the WOMAC index, before and 6 weeks after surgery (Western-Ontario-McMaster-Universities-Osteoarthritis-Index).
Time frame: 6 weeks after surgery
Visual Analogue Scale (VAS) for pain at rest
Time frame: 6 weeks after surgery
Visual Analogue Scale (VAS) for pain at movement
Time frame: 6 weeks after surgery
Pain medication consumption
Time frame: 6 weeks after surgery
Visual Analogue Scale (VAS) for pain at rest
Time frame: first 24 hours after surgery
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Visual Analogue Scale (VAS) for pain at movement
Time frame: First 24 hours after surgery
CHAMPS (Community Healthy Activities Model Program for Seniors) questionnaire
Time frame: 6 weeks after surgery