The genicular nerves are the nerves in and around the knee, and denervation is a procedure to block pain signals from the knee which travel in these nerves. The procedure is often recommended to treat knee pain, particularly knee pain caused by osteoarthritis.
Genicular nerve denervation, sometimes also referred to as radiofrequency ablation (RFA) or pulsed radiofrequency (PRF) - depending on the precise technique used - involves stopping pain signals via the nerve by blocking the nerve itself using 'ablation', which is where a small section of the tissue of the nerve is disabled.
The procedure is recommended where…
- The patient has chronic knee pain due to osteoarthritis.
- The patient has had a knee replacement failure.
- The patient is unsuited to knee replacement surgery.
- The patient wishes to avoid surgery or ongoing use of medication or other nerve blocks.
As the procedure is conducted under anaesthetic, you will need to fast, that is eat no food, in the 8 hours immediately prior to the procedure. You will also need to advise us if you are currently taking any medication, especially anti-coagulant medication, and you may need to stop taking some or all of your medications prior to the procedure. We will be able to advise you exactly how to prepare well ahead of the day.
A genicular nerve denervation is carried out under either a local anaesthetic or mild sedation to alleviate pain, however the patient remains awake during the procedure. The whole procedure generally takes less than an hour.
The patient is positioned on his/her back with the affected knee raised on a small pillow. A number of small needles are inserted into the knee, which are guided to the correct location in the knee using x-ray imaging.
Once the needles are in the place, electrodes are inserted via the needles and are then used to stimulate the nerve. This should produce a tingling sensation, which indicates that the electrodes are positioned correctly and that the procedure should result in pain being blocked.
When this is established, a low radiofrequency current is passed through the electrodes which produces highly localised heat which in turn disables the relevant section of the nerve. If necessary, a number of nerve locations may be treated during the one procedure.
The procedure may be preceded (a few days before) by a diagnostic nerve block, where local anaesthetic is injected into the knee to determine whether a denervation procedure will be successful in reducing the pain.
Once the procedure is complete, you should be able to return home after a short period of observation. It is advisable to have someone pick you up rather than drive yourself, due to any temporary effects of the anesthetic.
There may be some pain and/or discomfort where the needles were inserted into the knee. This should resolve on its own within a few days.
It can take 2-3 weeks for your knee pain to reduce or disappear after the procedure – this is normal.
Most patients are able to resume normal day-to-day activities almost immediately after the procedure, however if you had any restrictions to specific activities or movements before the procedure, you should continue to observe these.
You will be asked to come in for a follow up appointment around 14 days after the procedure.
As with all medical procedures, there is always a small risk that complication may develop afterwards. With a genicular nerve denervation procedure, there is a small risk of…
- Altered sensation or temporary increase in pain level.
- Bleeding from the needle insertion site/s.
- Numbness at needle insertion site/s.
- Small scars at needle insertion site/s.
- Infection at needle insertion site/s.
- Skin burn from electrode tip.
- Injury to other nerves, which may cause numbness or weakness, although this is generally only temporary.
- Allergic reaction to anaesthetic.