A femoral nerve block is an injection of medication near a major nerve in your leg. Healthcare providers mainly use these blocks to provide regional anesthesia for thigh and knee surgeries. You may also receive a femoral nerve block in an emergency room if you break your hip or femur.
A femoral nerve block is an injection of medication close to your femoral nerve to provide temporary pain relief (analgesia) or regional anesthesia. It can be a single injection or a continuous flow of medication.
Your femoral nerve is one of the largest nerves in your leg. It runs down the front of your thigh. Your femoral nerve has a motor function to help you move your hips, legs, ankles and feet. It also has a sensory function, helping you feel touch, pain and hot or cold temperatures. A femoral nerve block prevents pain signals from reaching your brain. But it can also temporarily “paralyze” your thigh and hip muscles for as long as the medication’s in effect.
Healthcare providers mainly use femoral nerve blocks to provide regional anesthesia for procedures in your thigh or knee regions.
Healthcare providers inject a femoral nerve block in the middle of your upper thigh near your pelvis. Your femoral nerve comes from the lumbar plexus nerves. These are a collection of nerves that arise from the lumbar — or lower back — section of your spinal cord.
A femoral nerve block can temporarily affect your quad muscles (quadriceps femoris) — the muscles in front of your thigh — and hip flexor muscles (the psoas major and iliacus muscles).
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Healthcare providers mainly use femoral nerve blocks for certain surgeries and to provide pain relief for acute (sudden and severe) injuries.
Surgeons use femoral nerve blocks to provide regional anesthesia for several procedures, including:
Surgeons also use femoral nerve blocks to manage your pain after major femur (thigh bone) and knee surgeries, such as a total knee replacement. This is usually a continuous nerve block.
Healthcare providers may use femoral nerve blocks to provide pain relief after you experience certain severe injuries, like:
Providers typically perform these blocks in an emergency department. They make it more comfortable for you when providers give physical exams and take X-rays. It also helps relieve pain if your provider needs to reset displaced broken bones (manipulation or closed reduction).
If you’re getting a femoral nerve block for pain relief from an acute injury, you usually don’t have to do anything special to prepare.
If you’re getting a femoral nerve block for surgery, your provider will give you specific instructions. For example, you might need to fast (not eat or drink anything except water) before the surgery or stop taking certain medications.
The process for a femoral nerve block can vary slightly depending on if it’s for acute pain or surgery. It can also vary if it’s a single injection or a continuous flow with a catheter.
In general, you can expect the following when you receive a femoral nerve block:
Femoral nerve blocks are often very effective for temporarily blocking pain.
For surgeries and acute injuries, a femoral nerve block can provide effective pain relief with a lesser need for opioid medications. As opioids have high addiction potential, this reduces the possible adverse effects of taking opioids. It may also allow you to leave the hospital earlier than if you were to take opioids only.
Complications of femoral nerve blocks are rare but can include:
A femoral nerve block can increase your risk of falls as you recover from surgery in the hospital. This is because it can cause weakness in your quad muscles. Your healthcare team will discuss this with you and teach you how to prevent falls.
How long a femoral nerve block lasts can vary considerably.
The type, strength and dose of the anesthetic your healthcare provider uses affect the onset, duration and spread of the nerve block. Your provider will be able to give you a better idea of what to expect based on your unique situation.
In some cases, the nerve block might not work. Your healthcare team will provide other options for pain relief.
Contact your healthcare provider immediately if you experience any new symptoms or complications from the femoral nerve block, such as an infection or nerve issues like burning pain, weakness or tingling.
A note from Cleveland Clinic
Femoral nerve blocks are a common and effective regional anesthesia method for various procedures affecting your thigh or knee. They can also provide temporary pain relief from certain bone fractures. If you’re feeling anxious about receiving a femoral nerve block, don’t hesitate to ask your healthcare provider about it and the procedure. They can answer any questions you may have.
Last reviewed by a Cleveland Clinic medical professional on 04/19/2023.
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