Knee Joint Cooled RFA

In conventional RFA, the probe tip reaches 80°C and creates a relatively small lesion. In Cooled RFA, internal water cooling circulates around the probe tip, keeping it cooler while allowing the surrounding tissue to reach ablation temperature. This creates a significantly larger and more spherical lesion, important for the genicular nerves because they run in a variable position beneath the periosteum and can be difficult to pin down to a millimetre. The larger lesion built by cooled technology improves the chance of capturing the nerve and sustaining relief. Nerve stimulation is not required with Cooled RFA because of this anatomically defined positioning system.

Suitable patients include those with moderate-to-severe knee osteoarthritis who have not had adequate sustained relief from steroid or hyaluronic acid injections, or whose relief from injections has become shorter with each cycle. A prior positive genicular nerve block (≥50% relief for at least a few days) is usually required. Patients who are not surgical candidates for knee replacement, or who wish to delay surgery, are also good candidates.

You lie on your back on the fluoroscopy table. The knee area is cleaned and draped. Under live X-ray guidance, three cooled RF probes are positioned at the standard genicular nerve landmarks: the SM probe at the junction of the femur shaft and medial condyle, the SL probe at the junction of the femur shaft and lateral condyle, and the IM probe at the junction of the tibial shaft and medial condyle. Local anaesthetic is given at each site. The cooled RF generator then applies energy to each probe sequentially. The procedure takes approximately 60-90 minutes.

Expect mild soreness around the knee for 1–2 weeks. This is the normal tissue response to heat. Pain relief begins to build from 2–4 weeks as the ablated nerve fibres stop transmitting pain. Full benefit is usually seen at 4–8 weeks. Most patients are able to increase their walking distance and daily activity progressively during this period.

Clinical studies report pain relief lasting 12 months or more in the majority of patients. Some patients have reported sustained relief at 2+ years. The genicular nerves can regenerate over time, but repeat procedures are safe and well-tolerated. Cooled RFA consistently outperforms conventional RFA and single steroid injections in published comparative studies for knee osteoarthritis.

Yes. Persistent pain after total knee arthroplasty (TKA) affects 10–20% of patients, and the genicular nerves can continue to carry pain from the joint capsule even after the joint surfaces have been replaced. Cooled RFA of the genicular nerves is an established option for post-TKA pain, with good success rates reported in this patient group. The metal implant does not interfere with fluoroscopic guidance or the ablation.