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.

Radiofrequency thermocoagulation of the genicular nerves

Using the numerical rating score , a score from ( 0 to 10 ) for evaluation of pain intensity. The 11-point numeric scale ranges from '0' representing one pain extreme (e.g. "no pain") to '10' representing the other pain extreme (e.g. "pain as bad as you can imagine" or "worst pain imaginable").

Using oxford knee score for follow up of pain of knee osteoarthritis , a score from 0 to 48 . if the score is 0 to 19 this may indicate sever arthritis , and if it's from 40 to 48 it means satisfactory joint function . This scrore is based on a 12-question report about an individual's level of function, activities of daily living and how they have been affected by pain over the preceding four weeks.

Duration of pain free periods since the intervention has been done

Patients undergo physical knee examination to determine the site of knee pain at right or left knee , medial or lateral joint line