Review Question - QID 107191

This patient is most likely suffering from knee osteoarthritis. Often, the diagnosis of osteoarthritis can be made solely on the clinical history and physical exam findings, without any additional laboratory or radiographic evaluations; however, radiographs may be useful in a preliminary work-up.

Osteoarthritis is most commonly seen in patients over 40 years of age, with an increasing prevalence with advancing age. The most common sites of involvement include the hip, knee, vertebrae, and hands. It presents with joint pain, crepitus, and no systemic manifestations. In contrast to a diagnosis of rheumatoid arthritis, symptoms are worsened by continued activity and improved with periods of rest, with minimal morning stiffness lasting less than 30 minutes. Laboratory values, including joint aspiration, are normal; radiographs may show osteophyte formation, joint-space loss, subchondral cysts/sclerosis, or loose bodies in the joint.

Hauk reviews the management of knee osteoarthritis. Conservative treatment should include self-management, strengthening exercises, low-impact aerobic exercise, neuromuscular education, and weight loss for patients with BMI > 25. Oral or topical nonsteroidal anti-inflammatory medications or tramadol can be beneficial. Corticosteroid joint injections and surgical intervention are other options if these more conservative measures do not sufficiently alleviate the patient's symptoms.

Strand et al. discuss the safety and efficacy of viscosupplementation in the treatment of knee osteoarthritis. A randomized, placebo-controlled trial of almost 5,000 patients showed statistically significant improvements in knee pain and function for patients receiving viscosupplementation over a saline control. There were no differences in safety or adverse effects between the treatment and control groups through 26 weeks.

Illustration A summarizes the findings in knee osteoarthritis. Illustration B shows a knee radiograph of a patient with osteoarthritis; note the narrowed joint space, varus deformity, and osteophyte formation. Illustration C is a chart contrasting osteoarthritis with rheumatoid arthritis; note that the wrist, MCP, and PIP joints are more commonly involved in RA versus the PIP and DIP joints in OA.

Incorrect Answers:
Answer 1: A complete blood count should be normal in a patient with osteoarthritis and would not contribute to making or confirming the diagnosis.
Answer 2: ESR is an inflammatory marker that would not be expected to be elevated in cases of osteoarthritis.
Answer 3: Rheumatoid factor is elevated in patients with rheumatoid arthritis, which has a differing presentation from that seen in the patient in this vignette.
Answer 4: A knee radiograph would be an appropriate test to order to confirm the diagnosis of osteoarthritis; an MRI is rarely ever the first imaging test that should be ordered.