The knees are complex structures that we ask a lot of during our lifetime. They support the weight of our body and help us move through the world. We use them when lifting heavy things and climbing endless flights of stairs (or logging endless miles on the road, running). Eventually all of the pressure and movement can begin to wear on this joint, causing pain and potentially serious damage if left untreated. Sometimes knee surgery is the way to go, but sometimes that’s not an option due to other chronic conditions. Sometimes knee surgery isn’t even the best choice. Instead of more invasive surgical options, many patients turn to a genicular nerve block to treat and diagnose persistent knee pain.
What is a genicular nerve block?
A genicular nerve block is a minimally-invasive procedure used to relieve pain caused by a variety of chronic pain conditions. These can include:
- Severe osteoarthritis in the knees
- Pain due to total or partial knee replacements
- Chronic knee pain in patients who cannot have surgery
- Degenerative joint disease
The knee joint consists of just three bones: the femur, tibia, and patella (your kneecap). These three simple bones are held together by a complex network of cartilage, ligaments, and tendons. Cartilage helps to cushion and lubricate the area where bones meet. Ligaments connect the bones to each other. Tendons connect the muscles to the bones.
All of these different types of anatomy are crisscrossed and enervated by a network of femoral, common peroneal, saphenous, tibial, and obturator nerves. Each type of nerve is the relay for pain signals that originate in a different area of your knee. These nerves are broadly known as genicular nerves.
A genicular nerve block uses anesthetic injected into one or more of the genicular nerves, typically into one of three branches: the superior medial, the superior lateral, and the interior medial genicular nerves. This anesthetic interrupts pain signals being sent to the brain and can bring you tremendous relief from pain.
Genicular nerve blocks for knee pain fall under the category of selective nerve root blocks and sympathetic nerve blocks. Both of these are simply broader terminology for a pain management treatment that targets nerves to block pain signals. Sciatic nerve blocks for pain in the lumbar spine and radiating down the buttocks and legs are also a common type of nerve block.
How does a genicular nerve block help knee pain?
A genicular nerve block for knee pain can help target the area of your pain. Pain can occur anywhere in the knee joint. Injections of anesthetic can help patients experiencing pain to become or stay more active.
This is important because, often, knee pain sets off a health crisis that can steadily worsen.
A person experiencing knee pain may stop moving around as much. Not only can this cause loss of mobility in an already-sore joint, it can also cause weight gain which adds pressure to the knee. More pressure equals more pain, which in turn equals less mobility.
A genicular nerve block for knee pain can break this cycle long enough to help patients regain mobility and stay healthy.
In addition, genicular nerve blocks are also used as a diagnostic tool. Doctors can block pain signals from one area to determine what the cause of your pain might be. This is a simple way to provide more targeted and effective pain management.
In some cases, a genicular nerve block may be used in conjunction with surgical interventions to improve post-operative pain.
What should I expect during a knee genicular nerve block?
A successful genicular nerve block starts with conscientious pre-operative care. Your doctor’s instructions may vary depending on your individual health and circumstances, but in general, you can expect the following before, during, and after a genicular knee block. If this advice differs from your doctor’s, always follow your doctor’s advice first and foremost.
Your doctor will likely instruct you to stop taking any type of blood thinner at least seven days prior to your genicular nerve block. These include:
- Plavix (Clopidogrel)
- Pletal (Cilostazol)
- Prasugrel (Effient)
Exceptions to the above are Ticlid (Ticopidine 14 days prior) and Eliquis or Xarelto (five days prior).
Blood thinners can present complications when there are injections, and it is best to press “pause” when you have a genicular nerve block.
Herbal supplements, fish oil, and other herbal medications or teas should be paused three days before your procedure and only resumed when your doctor gives you the okay. Always be frank with your doctor about any additional supplements or vitamins you’re taking as these could interact harmfully with your other treatments.
Diabetics who take oral medicine are generally advised to skip their morning medication if they are getting their genicular nerve block in the morning.
On the day of your genicular nerve block, you must be in good health, with no fever, and not taking antibiotics. Most doctors will advise you not to eat anything after midnight the night before and to limit water to a few sips. Should you decide you need sedation during the procedure, the doctor will want that administered on an empty stomach.
Once you are all clear to proceed, you will lie down, possibly with a pillow under your knee. If you choose to have sedation, you will be attached to monitors and have an IV placed to deliver the medicine. Your doctor will carefully clean and disinfect the area of injection. A numbing agent (usually bupivacaine) will be injected into the injection site.
Using fluoroscopy or ultrasound, your doctor will identify the genicular nerves to be targeted. With a slightly larger needle, your doctor will inject a steroid (often methylprednisolone) and local anesthetics (again, bupivicaine). Many people experience immediate pain relief as the medications touch the nerves.
The whole procedure takes between 15 and 30 minutes (perhaps longer for those patients who receive sedation).
Post-operative care and following your doctor’s instructions is crucial to proper healing and long-lasting results. Your doctor may have additional restrictions based on your individual circumstances. The post-operative care below is a general guideline only and will differ largely if you’re receiving a block before another surgery.
If you have received IV sedation you must have a responsible adult drive you home from your procedure. Even though your sedation for genicular nerve block will be light, you may still feel groggy and disoriented. Dizziness, lightheadedness, and nausea are common side effects of sedation. Drink water and eat lightly until the effects begin to wear off. It’s important be with a friend while you emerge from sedation, at least for 24 hours. If you cannot manage that, make sure you have an emergency contact who can come to your aide if needed.
It is also important to avoid heavy or strenuous activity for 24 hours after your genicular nerve block. You may feel such relief after your nerve block that you want to run a marathon! Resist the urge and allow yourself time to rest and recover. Imagine how wonderful it will be to move without pain, and give yourself at least a day off.
Diabetic patients who have skipped their oral insulin may find their blood sugar is higher for a week or so after the genicular nerve block. Continue to be diligent in checking sugar levels and make sure to treat them accordingly.
Most patients can resume their normal diet the same day of the procedure and regular levels of activity the day after. Minor swelling can be treated with ice and ibuprofen as needed. On your doctor’s approval, you can begin taking your other medications as prescribed after the genicular nerve block is completed.
How long does a genicular nerve block last?
A genicular nerve block’s effects can last anywhere from eight to 24 hours. One of the reasons doctors use genicular nerve bloc