Genicular nerve block with or without radiofrequency ablation

Genicular Nerve Block with or without Radiofrequency Ablation

Patient Information

Chronic Pain

• Author ID:           LB
• Leaflet Ref:         Pain 044
• Version:              2
• Leaflet title:         Genicular nerve block with or without radiofrequency ablation.
• Date Produced:   October 2024
• Expiry Date:        October 2026

Introduction

A Genicular nerve block, with or without Radiofrequency Ablation, is a procedure in which some of the sensory nerve supply to the knee is blocked in order to provide pain relief.

 A Genicular nerve block on its own is usually done with local anaesthetic only, to determine whether blocking the nerve will help with the knee pain. This procedure does not usually provide longer lasting pain relief, sometimes only a few hours, as it is designed as a test block to assess suitability of radiofrequency ablation treatment.

Some Doctors will use local anaesthetic and steroid for the genicular nerve block, in which case the pain relief can last for a longer period of time.

 Your doctor may ask you to keep a pain diary after the procedure. If the Genicular nerve block procedure, with local anaesthetic only, does help, then the doctor can proceed to carry out Radiofrequency Ablation, either on the same day or at another appointment.

Radiofrequency Ablation is a procedure where a slightly bigger needle is used and where the temperature at its tip can be closely controlled.  Using an electrical current, the nerve is cauterised/destroyed.  The technical term for this is Ablation. Those patients suitable for a Genicular nerve block would include:

• Patients with chronic knee pain
• Patients with failed knee surgery
• Patients who are unfit for a knee replacement
• Patients who want to avoid surgery

What you must do before the procedure 

The doctor or nurse will discuss the procedure in clinic before booking the treatment. If there is a possibility that you may be pregnant, please let us know. Consent for the procedure will be taken on the day, and the procedure will be carried out in a treatment room or operating theatre under sterile conditions. It is done as a day case procedure, and you will have to stay between 1-2 hours afterwards. If you have the Genicular nerve test blocks and the Radiofrequency Ablation on the same day, you should plan to be in hospital for half a day. You will not be able to drive immediately afterwards, so someone will have to transport you home, and you would need to be able to contact someone who could provide help in an emergency later if needed

During the procedure 

You may have a small cannula or ‘drip’ in the back of your hand, to enable the doctor to administer fluids if required. Blood pressure and heart rate monitors will be attached to you. 

The doctor will then inject the knee with the local anaesthetic. You will be sent back to the ward and then the effect will be reviewed about 40 mins later. If the Radiofrequency Ablation is then an option, you will be transferred back to theatre, and a sticky pad will be applied to your thigh to complete the electrical circuit. 

Should your doctor have planned with you to have the Radiofrequency procedure on a different day, you can go home after the nerve blocks, and you will be given a pain diary to assess the effectiveness of the treatment; this will help the medical staff to decide whether the longer-lasting treatment of Radiofrequency Ablation of the genicular nerves would be suitable and helpful to you for pain relief. 

The Radiofrequency Ablation procedure will be carried out with full asepsis (sterile and antiseptic precautions) in order to reduce the risk of infection. The doctor will use an X-ray or ultrasound machine to help with the procedure. 

 The special Radio frequency needles will then be inserted. You will be given further local anaesthetic to cover the procedure.  The machine will then be set to heat the nerve for 1 to 2 minutes. This process will be repeated for each nerve that is due to be treated, which will be 3 at the most. 

Aims

Our aim is to provide pain relief to the knee. There is no guarantee that the treatment will work, or that it will last for a specific time, if it does work. The pain-relieving effect can last up to a year if the treatment is successful. 

Risks

Overall, this procedure has very few risks. However, as with any procedure, there are some risks and side effects that you should know about. Common side effects are failure of pain relief, increased pain from the injection (usually temporary), infection (rarely), bleeding and nerve damage. As a nerve is being deliberately destroyed, this can cause the onset of a different type of pain called a dysaesthetic pain, which some patients may find troublesome. This usually subsides after some time but could potentially persist.  There is a small risk of bone damage. 

Alternatives

Your pain specialist may have discussed alternatives with you during your initial consultation.  These could either be medicines, different injections, physical therapies or self-management.  Every patient is unique and therefore specific alternatives cannot be given on an information leaflet, as not all treatments are suitable for everyone.

Aftercare

It is important that you have a responsible adult to escort you home and someone who could help you later if needed.  You must not drive or use public transport for the journey home.  It is recommended that you rest for the remainder of the day.

You may have some numbness and weakness surrounding your normally painful area, and procedure site for some hours after your procedure; this is due to the local anaesthetic given. This is normal, but if you are concerned, please contact us.

It is normal to be tender at the procedure site for a short period of time afterwards. If there is redness, swelling and increased temperature of the skin, please contact us. If this is at a time when we are not open, please contact your GP or go to A&E if the swelling and other changes are significant.

You will be given a follow up appointment to review the outcome of the procedure, either face to face or over the telephone; please let us know which you prefer.

Will the steroid injection affect how well my COVID vaccine will work? 

For a non-essential steroid injection, any vaccine you have, including the Flu vaccine, Shingles or the RSV vaccine, should be delayed by 2 weeks after the steroid injection and not be given within 2 weeks before a cortisone injection.

Where a patient has booked their injection appointment with the booking team and they subsequently are notified of their vaccination date, which falls within the 2 weeks either side of their steroid injection, they are advised to contact the booking team to rearrange their pain injection. Or contact their vaccine provider to discuss rearranging their vaccination appointment. Should patients not follow this advice they risk being cancelled on the day.