Avi Rudin: A 68-Year-Old Male With Anterior Thigh and Medial Calf Pain and Difficulty Walking Up Stairs

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Learn the common causes of lower extremity numbness.
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Develop an understanding of the anatomy of the femoral nerve.
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Develop an understanding of the unique relationship of the femoral nerve to the inguinal ligament.
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Develop an understanding of the unique relationship of the femoral nerve to the femoral artery and vein.
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Develop an understanding of the causes of femoral neuropathy.
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Develop an understanding of the differential diagnosis of lower extremity pain and numbness.
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Learn the clinical presentation of femoral neuropathy.
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Learn the dermatomes of the lower extremity.
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Learn how to use physical examination to identify femoral neuropathy.
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Develop an understanding of the treatment options for femoral neuropathy.

Avi Rudin

Avi Rudin is a 68-year-old violinist with the chief complaint of, “Ever since my cardiac cath, I’ve had pain and numbness in my left leg.” Avi stated that a couple of months ago, he was shoveling snow off his front walk when he began having crushing chest pain and lightheadedness. He called 911 and was rushed to the emergency room. He was seen by a cardiologist who diagnosed an ST-elevation myocardial infarction (STEMI) and suggested a cardiac catherization with probable angioplasty and coronary artery stent. Avi said that he doesn’t remember much about the cardiac catherization, but clearly remembers feeling an electric shock that went down his leg when the doctor put the needle into his groin. Avi went on to say that the cath “didn’t work” and he had to have a four-vessel cardiac bypass. The first thing he remembered when he woke up after his surgery was this burning pain that ran from his groin into the front of his left leg and then down into his medial calf. He said his chest incision hurt, but it was the leg pain that really bothered him. Avi said that his doctor told him not to worry, that it was just a little nerve irritation from the cardiac cath and it would get better with time, but it never did.

I asked Avi if he had experienced any numbness or weakness in his legs and he replied, “Doc, it’s funny that you asked because over the last couple of weeks, I have really had a lot of trouble walking up stairs or lifting my leg up to put on my socks.” “Both legs?” I asked, and he said “No, just the left.” I asked Avi what he had tried to make it better and he said that massaging his thigh seemed to help a little, but the pain pills he had for after his heart surgery just made him sick to his stomach, so he quit taking them.

He also volunteered that he had stopped wearing pajama bottoms to bed because the skin over the painful area was so sensitive, “kind of like a sunburn,” Avi reported. “Also, Tylenol PM seems to help some, at least with sleep.”

I asked Avi to show me where the pain was and he pointed to his left anterior thigh and then reached down and patted his medial calf. I asked Avi about any fever, chills or other constitutional symptoms such as weight loss, night sweats, etc., and he shook his head no. He denied any further chest pain, but said the pain often woke him up at night.

On physical examination, Avi was afebrile. His respirations were 18, his pulse was 74 and regular, and his blood pressure was 122/78. Avi’s head, eyes, ears, nose, throat (HEENT) exam was normal, as was his thyroid exam. Auscultation of his carotids revealed no bruits, and the pulses in all four extremities were normal. He had a regular rhythm without abnormal beats. His cardiac exam was otherwise unremarkable. There was a well-healed median sternotomy scar without defect or evidence of infection. His abdominal examination revealed no abnormal mass or organomegaly. There was no peripheral edema. His low back examination was unremarkable. There was no costovertebral angle (CVA) tenderness. Visual inspection of the left lower extremity was unremarkable. There was no rubor or color, but there was mild allodynia in the distribution of the femoral nerve on the left. There was no obvious infection. There was no femoral bruit. Examination of his right lower extremity revealed a well-healed scar from harvest of his saphenous vein for his coronary artery grafts.

A careful neurologic examination of both lower extremities revealed decreased sensation in the distribution of the left femoral nerve and marked weakness of the left quadriceps muscle ( Fig. 9.1 ). His femoral stretch test on the left was markedly positive ( Fig. 9.2 ). The right lower extremity neurologic examination was completely normal, other than subtle numbness in the distribution of his saphenous nerve, presumably from the vein harvest. Deep tendon reflexes were normal except for a decreased knee jerk on the left. There was a positive Tinel sign over the left femoral nerve.

Key Clinical Points—What’s Important and What’s Not

The History

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A history of the onset of anterior thigh and medial calf pain immediately following a cardiac catherization
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Difficulty walking up stairs
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Difficulty fully extending the left leg
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Pain has a sunburn like quality
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No symptoms in the right lower extremity
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No fever or chills
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History of recent coronary artery bypass surgery

The Physical Examination

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The patient is afebrile
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Marked weakness of the quadriceps muscle on the left
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Numbness in the distribution of the femoral nerve on the left (see Fig. 9.1 )
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Positive femoral stretch test (see Fig. 9.2 )
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Positive Tinel sign over the femoral nerve on the left
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Allodynia in the distribution of the left femoral nerve
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No motor deficit in the right lower extremity
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Deep tendon reflexes within normal limits bilaterally except for a decreased knee jerk on the left

Other Findings of Note

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Normal HEENT examination
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Normal cardiovascular examination
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Normal pulmonary examination
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Normal abdominal examination
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No peripheral edema
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No carotid or femoral bruits

What Tests Would You Like to Order?

The following tests were ordered:

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Ultrasound of the left femoral nerve at the level of the inguinal ligament
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Electromyography (EMG) and nerve conduction velocity testing of the left femoral nerve

Test Results

Ultrasound examination of the femoral nerve at the level of the femoral triangle reveals no obvious tumor or mass compressing the femoral nerve ( Fig. 9.3 ). EMG and nerve conduction velocity testing revealed slowing of femoral nerve conduction across the femoral triangle. Needle examination reveals marked denervation of the quadriceps muscle