Will Graham: A 24-Year-Old Youth Pastor With Posterior Left Knee Swelling and Pain

Learning Objectives

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Learn the common causes of knee pain.
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Learn the common causes of Baker cyst.
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Develop an understanding of the anatomy of the popliteal fossa.
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Develop an understanding of the differential diagnosis of Baker cyst.
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Learn the clinical presentation of Baker cyst.
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Learn how to examine the knee.
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Learn how to examine the popliteal fossa.
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Learn how to use physical examination to identify Baker cyst.
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Develop an understanding of the treatment options for Baker cyst.

Will Graham

Will Graham is a 24-year-old youth pastor with the chief complaint of, “I’ve got a bump on the back of my left knee.” Will stated that his problems came on over the last month or so. He was leading a youth retreat and they went on a hike, and one of his kids asked what was going on with the back of his knee. He felt the bump on the back of his knee and his first thought was a spider bite. When it didn’t get better over the next few days, he began to wonder if he had a tumor on his knee. “Doc, I have so much going on with my rheumatoid arthritis [RA] that I probably don’t pay as much attention to things as I should, but this really scared me because it was a little bigger each day and it started to hurt. Then, the crazy thing was that if I was up on my feet a lot, I started getting some numbness and tingling down the front of my leg. I tried using a heating pad, but I thought that it made the bump bigger, so I switched to ice packs. I have been taking Tylenol because my stomach can’t take the Motrin.” I asked, “What makes it worse?”

“Doc, like I said, if I am on my feet a lot, it gets worse and if I have to squat down to get something out of the bottom drawer of my file cabinet, it feels like the back of my knee is going to pop.”

I asked Will how he was sleeping and he shook his head and said, “Not very well. I pray on this, but I’m really scared that I have cancer. I’m really getting worn out.” I reassured him that I had a pretty good idea what was going on and it was not likely to be cancer. I told him we would get things figured out. “Just a few more questions and then let’s look you over,” I said. “Any fever, chills, or other constitutional symptoms such as weight loss, night sweats, etc.?” Will just shook his head no. I asked Will if he had ever had anything like this in the past and he said, “Not really, just the usual ups and down with my RA.”

On physical examination, Will was afebrile. His respirations were 16, his pulse was 66 and regular, and his blood pressure was 112/68. Will’s 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 his hands revealed some mild synovitis consistent with his rheumatoid arthritis. There was no ulnar drift. Examination of his left popliteal fossa revealed a firm, tender, cystic mass that was most likely a Baker cyst ( Fig. 12.1 ). There was no rubor, no obvious infection, or bursitis. There was no evidence of thrombophlebitis, and Homans sign was negative. Examination of Will’s feet revealed rheumatoid nodules consistent with his rheumatoid arthritis ( Fig. 12.2 ). A careful neurologic examination of the upper extremities was completely normal. Deep tendon reflexes were normal.

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

The History

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A history of the onset of left posterior knee swelling and pain
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History of rheumatoid arthritis
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No numbness
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No weakness
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No history of previous significant knee pain
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No fever or chills
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Sleep disturbance
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Pain on weightbearing and squatting

The Physical Examination

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The patient is afebrile
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Firm cystic mass in the left popliteal fossa
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Tenderness on palpation of the popliteal mass
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No thrombophlebitis of pseudothrobophebitis
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Rheumatoid nodules of the feet bilaterally
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Mild synovitis of the hands
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No ulnar drift
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Negative Homans sign
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No obvious bursitis
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No obvious infection

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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Normal upper extremity neurologic examination, motor and sensory examination

What Tests Would You Like to Order?

The following tests were ordered:

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Plain radiographs of the left knee
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Ultrasound of the left knee
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Magnetic resonance imaging (MRI) of the left knee

Test Results

The plain radiographs of the left knee revealed findings consistent with mild rheumatoid arthritis with no evidence of fracture. Ultrasound examination of the left knee revealed a large Baker cyst ( Fig. 12.3 ). MRI scan of the left knee reveals edema of the tibial insertions of semimembranosus muscle ( Fig. 12.4 ).