Mario Berbiglia: A 72-Year-Old Male With Medial Thigh Pain Following a Total Hip Arthroplasty

Learning Objectives

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Learn the common causes of lower extremity numbness.
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Develop an understanding of the unique relationship of the obturator nerve to the inguinal ligaments.
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Develop an understanding of the anatomy of the obturator nerve.
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Develop an understanding of the causes of obturator neuralgia.
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Develop an understanding of the differential diagnosis of obturator neuralgia.
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Learn the clinical presentation of obturator neuralgia.
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Learn the dermatomes of the lower extremity.
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Learn how to use physical examination to identify obturator neuralgia.
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Develop an understanding of the treatment options for obturator neuralgia.

Mario Berbiglia

Mario Berbiglia is a 72-year-old restaurant owner with the chief complaint of, “I’m having sharp pain in my inner thigh since that damn hip replacement.” Mario shook his head and said, “I should have never had it done, but I wanted to keep working and I thought it would help.” Mario went on to state that he had pain in his left inner thigh before he even got up to the side of the bed following his total hip arthroplasty. His orthopedic surgeon said that some pain after surgery was to be expected, but even when the postoperative pain went away, the thigh pain continued. Mario said that he was trying to do everything his physical therapist told him to do, but “the pain is really limiting my recovery, and now my left leg feels unsteady.” When he went back for his 8-week follow-up with the orthopedic surgeon, he felt like the surgeon couldn’t have cared less and finally told him that he would just have to learn to live with the pain, as the surgery was a complete success. Mario said, “Yeah, the surgery was a complete success, but the patient died! Doc, I am really getting discouraged. My kids are trying to keep the restaurant going, but my customers expect me to be there to greet them like I’ve been doing for the past 35 years. Villa Capri without Mario is like spaghetti without meatballs. I really need to get back to my customers, but I don’t want them to see me with this damn walker.”

I asked Mario to show me where the pain was, and he rubbed his left inner thigh ( Fig. 10.1 ). “Doc, it’s right here. There is always a deep ache and when I try to walk, I get electric shocks into the area. It’s really discouraging. What the hell did that doctor do to me? I should have never gone under the knife! I knew better.” I asked Mario about any fever, chills, or other constitutional symptoms such as weight loss, night sweats, etc., and he shook his head no. He also denied bowel or bladder symptomatology. He denied any antecedent lower extremity trauma, but noted that the pain woke him up “about 50 times a night” and that it was making him cranky.

He then asked, “Doc, tell me the truth. What do you think this guy did to me?” I clapped Mario on the shoulder and said that I would do my best to figure out what was going on and together we would come up with a plan to make it better.

On physical examination, Mario was afebrile. His respirations were 18, his pulse was 74 and regular, and his blood pressure was 132/78. His head, eyes, ears, nose, throat (HEENT) exam was normal, as was his cardiopulmonary examination. His thyroid was normal. His abdominal examination revealed no abnormal mass or organomegaly. There was no costovertebral angle (CVA) tenderness. There was no peripheral edema. His low back examination was unremarkable. Visual inspection of the left lower extremity was unremarkable other than his well-healed hip surgery scar. There was no obvious infection. There was no rubor or color in the painful area, and there was no evidence of abnormal mass or hernia. Rectal and testicular examinations were normal, other than a small external hemorrhoid. I asked Mario to walk down the hall. He did pretty well getting up with the help of his walker, but his gait was antalgic as he slowly walked down the hall. I also noted that Mario’s left foot was externally rotated (see accompanying photo on page 123).

A careful neurologic examination of both lower extremities revealed a slight decrease in sensation in the distribution of the left obturator nerve, but no sensory abnormalities below the knee were identified. A numb medial thigh sign was present ( Fig. 10.2 ). There was allodynia in the distribution of the obturator nerve on the left. His left lower extremity motor exam revealed moderate weakness of the hip adductors, which could account for that “unsteady feeling.” His right lower extremity neurologic examination was completely normal. Deep tendon reflexes were normal throughout the upper extremity, knee jerks were physiologic, and ankle jerks were trace but symmetrical bilaterally.

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

The History

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A history of the onset of medial thigh pain following a total hip arthroplasty
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A sense that the left lower extremity is “unsteady”
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Pain symptomatology limiting physical therapy
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Pain is characterized as a deep pain with electric shocklike pain into the medial thigh when ambulating
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No symptoms in the right lower extremity
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No fever or chills
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No bowel or bladder symptomatology

The Physical Examination

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The patient is afebrile
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Decreased sensation in the distribution of the left obturator nerve
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No sensory deficit below the knee on the left
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Allodynia in the distribution of the left obturator nerve
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Weakness of the hip adductors on the left
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No motor deficit in the right lower extremity
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Deep tendon reflexes are physiologic
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Antalgic gait

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 abnormal mass or hernia noted
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No peripheral edema

What Tests Would You Like to Order?

The following tests were ordered:

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X-ray of the left hip
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Computed tomography (CT) of the left hip
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Electromyography (EMG) and nerve conduction velocity testing of the left obturator nerve

Test Results

Anteroposterior radiograph of the left hip reveals extrapelvic cement extrusion from the total hip arthroplasty ( Fig. 10.3 ). CT of the left hip reveals intrapelvic extrusion of bone cement ( Fig. 10.4 ). EMG and nerve conduction velocity testing revealed slowing of obturator nerve conduction and denervation of the hip adductors on the left.