The femoral nerve starts at a nerve bundle in the lower back. It passes through the pelvic area and runs down the leg to the foot. The nerve affects feeling and movement of the thigh, hip, and knee. A femoral nerve block decreases sensation in these areas.
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Reasons for Procedure
Femoral nerve blocks are often used for pain relief. A femoral nerve block may be used to manage pain caused by:
- Fracture of hip or thigh bone
- Surgery on your leg
The block dulls sensation in the leg. This increases the risk of falls, which can cause or worsen injury.
Other problems are rare, but all procedures have some risk. The doctor will review possible problems such as:
What to Expect
Prior to Procedure
The doctor may review tests that were already done. Other steps will depend on the reason a block is needed.
The doctor needs to know about any medicine that you are currently taking. Certain medicine will need to be stopped up to 1 week before your procedure.
Local anesthesia will be used. It will numb the area where the injection will be made. A sedative may also be given. It will improve relaxation.
Description of the Procedure
This procedure may be done as treatment by itself or as part of your treatment.
You will be asked to lie on your back. The doctor will locate the femoral nerve by feel. An ultrasound machine may also be used to help guide the needle. The needle will be inserted through the skin and into the femoral nerve. More than 1 injection may be needed to get the needle into the correct place. You may feel your thigh muscle twitch when the nerve is touched by the needle. The medicine will be injected into the nerve and the needle will be removed.
How Long Will It Take?
15 to 20 minutes
Will It Hurt?
There may be some pressure when the needle is place. Medicine will block pain. The area may be sore after the nerve block wears off.
At the Hospital
Blood pressure and heart rate will be monitored.
Activity will be limited until the block wears off.
Call Your Doctor
It is important to monitor your recovery. Alert your doctor to any problems. Call your doctor if any of the following happen:
- Signs of infection, including fever and chills
- Redness, swelling, pain, or discharge from the insertion site
- Pain that does not go away with the medication you were given
- Excess bleeding from the insertion site
- Falls, especially if they result in injury
- Residual tingling, numbness, weakness or shooting pain in your leg
- Cough, shortness of breath, or chest pain
If you think you have an emergency, call for emergency medical services right away.
American Society of Anesthesiologist
Ortho Info—American Academy of Orthopaedic Surgeons
Canadian Anesthesiologists' Society
When it Hurts to Move—Canadian Orthopaedic Foundation
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Sharma S, Iorio R, Specht LM, Davies-Lepie S, Healy WL. Complications of femoral nerve block for total knee arthroplasty. Clin Orthop Relat Res. 2010;468(1):135-140.
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Last reviewed September 2019 by EBSCO Medical Review Board Marcin Chwistek, MD Last Updated: 9/11/2020