The morning session is over; the lunch hour is drawing to a close. I stand by the nurses' station, perusing my afternoon schedule. One entry catches my eye: a 15-year-old girl with bilateral knee pain for 3 months. As a mental exercise, I allow my thoughts to drift, formulating a differential diagnosis of sorts for this patient I have not previously seen.
I retire to the back office and pull the standard orthopedic text off the bookshelf. I slide into a chair at one of the desks and open the book. Quickly, I search the index, find the entry, and flip back through the pages. It doesn't take long to review the section. I close the book and return it to its position on the shelf.
My first patient of the afternoon is up: a 2-year-old with ear pain. Next is an 18-month-old for a well-child visit, then a college student with a nagging cough. The nurse hands me the chart for my next patient: the 15-year-old girl with knee pain. “She's here with her mother,” the nurse says, “one tough cookie.”
I review the vital signs, tuck the chart under my arm, and open the examination room door. Mother and daughter sit side by side in the two chairs by the examination table. The girl flashes a momentary smile; the mother's face is neutral.
“I understand that your knees have been bothering you,” I say. “When did the pain start?”
“A couple of months ago,” the mother says. “She was playing volleyball at the time. We thought it had something to do with that.”
“The pain got better after the season ended,” the girl says. “But then it came back after I started playing volleyball again.”
I move to open my mouth, but the mother interjects first. “She only plays volleyball once a week now—no regular practices. The pain comes up when she's well into the game and continues for the rest of the day.”
I nod my head. “Have you tried anything to help the pain—medication perhaps, ice?”
“Not really,” the mother says. “We didn't know what was causing it, and we didn't want to mask any symptoms.”
“Does the pain keep you up at night?” I ask. “Have you noticed any swelling or redness of either knee?”
The girl shakes her head no.
“Any history of trauma to either knee?”
Once again she shakes her head.
“Hop up on the exam table and let's have a look at your legs,” I say.
The girl ascends easily and takes her place. I perform a thorough exam of her hips, knees, ankles, and feet. I ask her to stroll down the hallway to check her gait. Afterward, I motion her to retire to the chair.
“There's no sign of an inflammatory process like arthritis,” I say, directing my comment to the mother. “She has full range of motion of all of the joints in her lower extremities. All of the internal ligaments appear to be intact. There's no sign of any fluid in the joints either.”
“So what do you think is causing the pain?”
“Something we see quite frequently in adolescent girls who do sports, particularly sports that involve jumping or running. It's called patellofemoral syndrome.”
Immediately, the mother engages her smartphone and taps the screen. “How do you spell that?” she asks.
I write down the diagnostic phrase and hand it to her.
“It has to do with the way the kneecap glides across the surface of the knee joint when we run, jump, and pivot,” I say. I launch into a detailed explanation of the anatomy of the knee joint, the Q-angle, the forces that come into play during flexion and extension.
The mother scrolls her smartphone, eyes glued to the screen. “So what can she do about the pain?” she asks.
“Ah, well, there are a number of exercises she can do to strengthen the big thigh muscles, along with daily stretching. She could wear knee sleeves during play, take some ibuprofen, and ice the knees to control the discomfort.”
“And if things don't improve?” the mother asks with the stone face of Queen Victoria's “We-are-not-amused” expression.
“Then we could consider an orthopedic referral or physical therapy,” I say.
“Well, you certainly seem to have covered it all,” the mother says, tapping the screen of her smartphone one last time.
I offer one last smile—the smile of the cat that ate the canary. It always behooves one to crack the books before the final examination, regardless of what sort of examination one might be facing.