This is a single center randomized controlled trial. Approximately 102 patients will be randomized to one of two treatment groups: cooled radiofrequency or conventional monopolar radiofrequency ablation. Patients with chronic knee pain, with moderate to severe osteoarthritis according to the Kellgren-Lawrence scale for at least 6 months who have failed conservative therapy will be screened for the study. Then, patients will be enrolled based on reporting ≥50% pain relief after a fluoroscopic guided single diagnostic block of the geniculate nerves (superior medial, superior lateral, and inferior medial) with 0.5 ml of local anesthetic (2% Lidocaine). Baseline data will be collected for all enrolled patients. Outcomes will be measured at 1, 4, 12, 24 and 52 weeks. Outcome measures will be: Visual analogue scale (VAS) both while at rest and during ambulation, Oxford knee scores, WOMAC, and global perceived effect.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
79
Radiofrequency ablation uses the electrical field generated by a radiofrequency probe inserted near a nerve responsible for pain. Chronic pain sensation in the knee is generated at the genicular nerves. The physician locates the affected genicular nerve by injecting an anesthetic (lidocaine) that produces a sensory nerve block (i.e. anesthetic pain relief). A radiofrequency probe is inserted percutaneously near the affected nerve using a cannula/introducer and is then connected to a radiofrequency generator. This is set to stimulate sensory and motor response, which allows the physician to adjust the probe position for effective and safe treatment. Then radiofrequency is applied to the tissue for a short time (up to 150 seconds) in order to generate a target temperature (no more than 80 degrees Celsius). The increase in the temperature of the tissue ablates the affected nerve producing pain relief.
The pain management radiofrequency consists of a radiofrequency generator, a radiofrequency probe and an introducer/cannula. The introducer cannula is used to percutaneously position the probe in the appropriate location for treatment. The radiofrequency probe is an electrode that delivers the electric field that heats up the tissue. In cooled radiofrequency the electrode is surrounded by a water jacket that cools it while heat is generated. The generator is the instrument that provides the radiofrequency according to a particular temperature and time program. Temperature, tissue impedance and radiofrequency power are lalso monitored by the generator.
Millennium Pain Center
Bloomington, Illinois, United States
Millennium Pain Center at Decatur Memorial Hospital
Decatur, Illinois, United States
Methodist Comprehensive Spine and Pain Center - Millennium Pain Center
Peoria, Illinois, United States
Evidence of Change in Knee Pain
A 100mm visual analog scale (VAS) score at 24 weeks post-treatment will be compared to baseline score to measure change in pain level. Change in Pain = (VAS at 24 weeks) - (VAS at baseline) The VAS consists of a 100 mm long line without marks between the 0 and 100 mm edges. Range of scale is 0 to 100 mm, where 0 means no pain and 100 mm means the worst pain imaginable. A negative change in VAS means a reduction in pain level after 24-weeks of treatment.
Time frame: 24 weeks
Evidence of Functional Changes
Standard score system (Oxford Knee Score) was used to assess functional changes at 24 weeks of treatment relative to baseline. The Oxford Knee Score (OKS) measures the level of function, activities of daily living and how they have been affected by knee pain. The OKS is a obtained from a 12-item patient reported questionnaire. Each item has 5 categories, scored from 0 to 4, with 0 being the worst outcome and 4 the best outcome of each item. The OKS is the sum of all item scores. Therefore, it ranges from 0 to 48, with 0 being the worst functional outcome possible and 48 is the best functional outcome possible. Change in OKS = (OKS at 24 weeks) - (OKS at baseline) A positive Change in OKS indicates an improvement in extent of function.
Time frame: 24 weeks
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