Genicular Nerve Block

Overview

A genicular nerve block involves injecting a combination of steroid medication and local anesthetic near specific nerves in the knee to provide temporary pain relief. These nerves, collectively known as genicular nerves, include branches of the femoral, common peroneal, saphenous, tibial, and obturator nerves. They provide sensory input to the knee and include:

  • Superolateral genicular nerve (SLGN)
  • Superomedial genicular nerve (SMGN)
  • Inferomedial genicular nerve (IMGN)
  • Inferolateral genicular nerve (ILGN)

With the exception of the ILGN, all these nerves can be safely targeted with a genicular nerve block. This procedure is commonly used for managing chronic knee pain and post-surgical pain, offering varied effectiveness from person to person.

Reasons for undergoing the procedure

A genicular nerve block can target several genicular nerves. It is commonly administered for two major purposes:

  • Reducing moderate to severe pain after knee surgery: In addition to general anesthesia and other peripheral nerve blocks, a genicular nerve block may be administered to help manage postoperative pain. It can also be used preoperative when undergoing a knee operation, such as a total knee replacement.
  • Relieving persistent knee pain: Knee osteoarthritis and injuries are two common reasons for chronic knee discomfort. A genicular nerve block may be suggested if the knee pain continues to worsen with conservative measures like physical therapy, NSAIDs, or steroid knee joint injections.

Risk

Potential side effects and risk associated with genicular nerve blocks include:

  • The drug unexpectedly reaching the common peroneal nerve, which could result in foot drop
  • The drug unexpectedly getting into the bloodstream
  • The drug accidentally getting into the knee joint
  • Bleeding
  • Infection

Generally, these complications are rare. Some soreness and minor bruising at the injection site is expected after the procedure, but these symptoms are usually mild and should resolve within a few days.

Before the procedure

For a genicular nerve block procedure requiring sedation, it’s important to fast for six to eight hours beforehand and arrange for transportation home afterward. Typically, no special preparation is needed, but healthcare providers will offer specific instructions if necessary.

During the procedure

Genicular nerve blocks typically lasts between five to 10 minutes to complete. It often begins with patients lying on their back with a small pillow placed under the affected knee for support. To help them relax, a mild sedative through an IV line may be administered.

The following may be expected during genicular nerve blocks:

  • After cleaning the knee region, the healthcare provider numbs the injection site with a local anesthetic, which could be slightly uncomfortable
  • The damaged nerves are carefully located using imaging tools like fluoroscopy or ultrasound
  • The medicine is injected in close proximity to the damaged nerves
  • Rest is required until the medication takes effect

Genicular nerve blocks is done on an outpatient basis, which means that the procedure is done without hospital admission, allowing patients to return home shortly after.

After the procedure

After a genicular nerve block, you can expect:

  • A 15-to-30-minute resting period to allow the medication to take effect.
  • Close monitoring for any unexpected side effects.
  • Once observed, you’ll be discharged and can return home.

Most patients can walk out of the facility without difficulty and typically resume normal activities immediately. It’s advised to take it easy for the remainder of the day following the procedure.

Outcome

People who undergone a genicular nerve block re advised to contact their healthcare provider immediately if they experience any new symptoms or complications following the procedure, such as:

  • Infection
  • Weakness
  • Tingling
  • Burning pain

The duration and effectiveness of pain relief from a genicular nerve block can vary widely among individuals. Relief may last from a few days to several weeks, months, or even years, but typically averages around three months. Some experience immediate relief within hours, while for others, it may take a few weeks for the steroid to become effective.

The possible advantages of a genicular nerve block include:

  • Short-term pain alleviation following knee surgery
  • Relieve discomfort for those whose health prevents them from having knee surgery
  • Either temporary or long-term pain management
  • A temporary or long-term decrease in inflammation within the injured nerves, which could promote healing

Genicular nerve ablation (GNA) is a procedure that offer relief that lasts approximately 18 months. This may be suggested for people who experience significant pain relief from a genicular nerve block.

It’s important to note that not everyone experiences pain relief from nerve blocks. If the desired relief is not achieved, exploring alternative treatment options may be necessary.