Comparing the Safety and Effectiveness of Radiofrequency Thermocoagulation on Genicular Nerve, Intraarticular Pulsed Radiofrequency With Steroid Injection in the Pain Management of Knee Osteoarthritis

The treatment of the patients in the radio frequency thermo-coagulation of the genicular nerves was conducted under the guidance of C-arm X-ray machine . The C-arm machine showed that the radiofrequency cannula needle was advanced percutaneously towards the periosteal areas connecting the shaft of the femur to bilateral epicondyles and the shaft of the tibia to the medial epicondyle while the lateral image showed that the depth of the needle insertion was about 50% of the diameter of the femur or tibia. The radiofrequency electrodes were connected and tested. These induced abnormal pain around the knee joint at 50 Hz and 0.1-0.3 V, but did not induce contraction of the muscles of the knee joint at 2 Hz and > 2.0 V. The location of the needle tip was confirmed by the C-arm, and 0.5 mL of 1% lidocaine was used for local anesthesia. The temperature of RFT was increased gradually to 70°C for 180 seconds.

The puncture site was selected in the middle of the medial or lateral edge of the patella. After local anesthesia was administered with 0.5% lidocaine, the radiofrequency cannula needle was inserted slowly between the patella and femoral condyles. The needle was gradually inserted into the joint cavity, and then a small volume of saline was administered using a syringe. If any resistance was encountered, which indicated that the needle tip was located in a ligament or tendon, the surgeon readjusted the needle tip until the injection proceeded without any significant resistance. After entering the joint cavity, the C-arm x-ray is used confirm that the cannula needle was located in the middle of the joint space. Subsequently, sensory stimulation using 50 Hz/2 Hz was performed at > 2 V, to prevent inducing pain or muscle contraction. Then, an automatic PRF mode ≤ 45 V (≤ 42°C, 2 Hz, pulse width of 20 ms) was administered for 300 seconds.

The puncture procedure was similar to that for the IAPRF group. After the cannula needle was inserted to the articular cavity, 1 mL compound betamethasone (2 mg betamethasone sodium phosphate and 5 mg betamethasone dipropionate) was injected. Then, the needle was withdrawn, and the puncture site was dressed aseptically.