Test your medicine knowledge with the MKSAP challenge, in partnership with the American College of Physicians.

A 76-year-old woman is evaluated for a 3-month history of left knee pain of moderate intensity that worsens with ambulation. She reports minimal pain at rest and no nocturnal pain. There are no clicking or locking symptoms. She has tried naproxen and ibuprofen but developed dyspepsia; acetaminophen provides mild to moderate relief. The patient has hypertension, hypercholesterolemia, and chronic stable angina. Medications are lisinopril, metoprolol, simvastatin, low-dose aspirin, and nitroglycerin as needed.

On physical examination, vital signs are normal. BMI is 32. Range of motion of the left knee elicits crepitus. There is a small effusion without redness or warmth and tenderness to palpation along the medial joint line. Testing for meniscal or ligamentous injury is negative.

Laboratory studies, including complete blood count and erythrocyte sedimentation rate, are normal.

Radiographs of the knee reveal medial tibiofemoral compartment joint-space narrowing and sclerosis; small medial osteophytes are present.

Which of the following is the next best step in management?

A: Add celecoxib
B: Add glucosamine sulfate
C: MRI of the knee
D: Weight loss and exercise

MKSAP Answer and Critique

The correct answer is D: Weight loss and exercise.

Weight loss and exercise are indicated for this patient with knee osteoarthritis. Her knee pain, which is worse with weight bearing, is suggestive of tibiofemoral knee osteoarthritis, a diagnosis supported by the presence of medial joint line tenderness and radiographic findings of medial tibiofemoral compartment joint-space narrowing. The strongest risk factors for osteoarthritis are advancing age, obesity, female gender, joint injury (caused by occupation, repetitive use, or actual trauma), and genetic factors. Obesity, in particular, is the most important modifiable risk factor for knee osteoarthritis. Several trials have demonstrated that weight loss and/or exercise programs can offer relief of pain and improved function comparable to the benefits of NSAID use. In long-term studies, sustained weight loss of approximately 6.8 kg (15 lb) has resulted in symptomatic relief.

Celecoxib carries an increased myocardial risk and is therefore not appropriate for this patient who has coronary artery disease. Although celecoxib has a lower risk of gastrointestinal ulcers than other NSAIDs, it can still cause dyspepsia, which occurred in this patient after taking naproxen and ibuprofen.

There have been several contradictory studies regarding glucosamine sulfate in the management of osteoarthritis. After several favorable smaller studies, a trial sponsored by the National Institutes of Health showed no effectiveness in reducing pain. A recently conducted meta-analysis also found negative results for the use of glucosamine sulfate.

MRI of the knee would be indicated to evaluate for meniscal or other ligamentous injuries, none of which is suggested by this patient’s history (the knee locking or giving way) or examination findings (negative examination for tendinous or ligamentous injury).

Key Point

• Obesity is the most important modifiable risk factor for knee osteoarthritis, and weight loss and exercise are recommended to reduce pain and improve function.

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