Femoral neuropathy, or femoral nerve dysfunction, occurs when you can’t move or feel part of your leg because your nerves are damaged. This can happen from an injury, prolonged pressure on the nerve, or nerve damage that is the result of disease. In most cases, this condition will go away without treatment. However, medications and physical therapy may be used if symptoms do not improve.
The femoral nerve is one of the largest nerves in your leg. Located near the groin, it controls the muscles that help straighten your leg and move your hips, and also provides feeling in the lower part of your leg and the front of your thigh. When this nerve is damaged, it affects your ability to walk and may cause problems with sensation in your leg and foot.
Damage to the femoral nerve can be caused by:
- direct injury
- a tumor or other growth blocks or traps part of your nerve
- prolonged pressure on the nerve
- pelvic fractures
- radiation to the pelvis
- hemorrhage or bleeding into the space behind the abdomen (the retroperitoneal space)
- a catheter placed into the femoral artery, as may be necessary for certain surgical procedures
Diabetes is a common cause of femoral neuropathy. Diabetes can cause widespread nerve damage due to fluctuations in blood sugar and blood pressure. Nerve damage that affects your legs, feet, toes, hands, and arms is known as peripheral neuropathy. Femoral neuropathy falls into this category.
According to the National Institute of Diabetes and Digestive and Kidney Diseases, diabetes is the most common cause of peripheral neuropathy neuropathy, especially among people who have had this disease for at least 25 years. The peripheral neuropathy of diabetes frequently affects the femoral nerve (NIDDK, 2012).
This nerve condition can lead to difficulties moving around. Your leg or knee might feel weak and you may be unable to put pressure on the affected leg.
You might also feel abnormal sensations in your legs. These feelings can range from your knee down to your toes. They include:
- numbness over the front of the thigh and inside of your leg (i.e., the side that faces your other leg)
- tingling over the front of the thigh and inside of your leg (and also in the lower leg and foot)
- numbness and tingling over any part of the leg
- dull aching pain in the genital region
- lower extremity weakness
- difficulty extending the knee
- feeling like your leg or knee is going to give out on you
Prolonged pressure placed on the femoral nerve can prevent blood from flowing in the affected area. The decreased blood flow can result in tissue damage.
If your nerve damage was caused by an injury, it may be possible that your femoral vein or artery were also damaged. This could cause dangerous internal bleeding. The femoral artery is a very large artery that lies close to the femoral nerve. In trauma they are often injured together. Injury to or bleeding in the artery can cause compression on the nerve.
Additionally, because the femoral nerve provides sensation to a major portion of the leg, injuries can occur due to this loss of sensation. Having weak leg muscles can also make you more prone to falling. Falls are of particular concern in older people as they can cause hip fractures—a major cause of death in very elderly people, particularly men.
To diagnose femoral neuropathy and its cause, your doctor will perform a comprehensive physical exam and ask questions about recent injuries or surgeries, as well as questions about your medical history.
To look for weakness, he or she will test specific muscles that have their sensation supplied by the femoral nerve. Your knee reflexes will be checked, and your doctor will ask about changes in feeling in the front part of the thigh and the middle part of the leg. The goal of the evaluation is to determine whether there is isolated femoral nerve involvement or whether more than one nerve is involved.
Additional testing might include:
Nerve conduction tests to check the speed of electrical impulses in your nerves. An abnormal response, such as a slow time for electrical signals to travel through your nerves, usually indicates damage.
Electromyography (EMG) should be performed after the nerve conduction test to see how well your muscles and nerves are working. This test records the electrical activity that is present in your muscles when the nerves that lead to them are active. The EMG will determine whether the muscle responds appropriately to stimulation. Certain medical conditions cause muscles to fire on their own—this indicates an abnormality, and can be uncovered by the EMG. Because nerves stimulate (and control) your muscles, the test can identify problems with both muscles and nerves.
MRI and CT
An MRI (magnetic resonance imaging) may be used to look for tumors, growths or any other masses in the area of the femoral nerve, which could cause compression on the nerve. MRI scans use radio waves and magnets to produce a detailed image of the part of your body that is being scanned.
The first step in treating femoral neuropathy is dealing with the underlying condition or cause. If compression on the nerve is the cause, the goal will be to relieve the compression. Occasionally in mild injuries, such as mild compression or a stretch injury, the problem may resolve spontaneously. For diabetics, bringing blood sugar levels back to normal may alleviate nerve dysfunction. If your nerve doesn’t improve on its own, you’ll need treatment. This usually involves medications and physical therapy.
You might have corticosteroid injections in your leg to reduce inflammation and get rid of any swelling that occurs. Pain medications can help relieve any pain and discomfort.
Physical therapy can help build up the strength in your leg muscles again. A physical therapist will have you do several exercises to strengthen and stretch your muscles. Undergoing physical therapy can reduce pain and help you regain your mobility.
You might need to use an orthopedic device, such as a brace, to assist you with walking. Usually a knee brace is used to prevent knee buckling.
Depending on how severe the nerve damage is and how much trouble you’re having moving around, you might also need occupational therapy. This type of therapy helps you learn to do regular tasks like bathing and other self-care activities. These tasks are called “activities of daily living.” Your doctor might also recommend vocational counseling if your condition forces you to find another line of work.
Your doctor might recommend surgery if you have a growth blocking your femoral nerve. Having the growth removed will relieve the pressure on your nerve.
Once the underlying condition is treated, you might be able to fully heal. If the underlying condition is not treated successfully or if the femoral nerve damage is severe, you might permanently lose feeling in that part of your leg or the ability to move it.
You can lower your risk of femoral neuropathy caused by diabetes by keeping your blood sugar levels under control. This helps protect your nerves from damage caused by this disease. Preventive measures would be directed at each individual cause.