A 38-year-old woman comes to the office due to left knee swelling for the past 3 weeks. The patient has type 2 diabetes mellitus and recently started an exercise program consisting of aerobics and running to lose weight and improve glycemic control. She reports no falls or trauma. BMI is 35 kg/m². On examination, the knees are not red or warm and demonstrate full range of motion. There is a 4-cm area of swelling in the anteromedial knee region 3 cm below the joint line. The swollen area is mildly tender on palpation. There is no joint line tenderness. A left knee x-ray reveals no abnormalities. Which of the following is the most appropriate next step in management of this patient's condition?

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11ec25c8_d2eb_fa6d_bc81_31a664772b57_MD0003_00 This patient has pes anserine bursitis (PAB) related to overuse. The anserine bursa is located over the medial tibial condyle distal to the joint line and deep to the pes anserinus tendon complex. Repetitive friction, exacerbated by mechanical derangements of the knees (eg, medial meniscus protrusion, medial collateral ligament displacement) and obesity, is thought to cause bursal swelling. PAB is part of a broader syndrome, pes anserinus pain syndrome, that also includes nonbursal causes of upper medial tibial pain. Initial management includes rest and nonsteroidal anti-inflammatory drugs. To enhance overall fitness and address underlying mechanical derangements, patients should also perform exercises that increase strength and flexibility of the quadriceps and hamstring muscles, which stabilize the knees. Weakness and tightness in these muscles increase the stress on the articular (eg, bone, ligament, cartilage) and periarticular (eg, bursa, tendon) tissues. An imbalance between these opposing muscles (eg, quadriceps stronger than hamstring muscles) can lead to injury to the weaker muscle (and tendon) when the stronger muscle contracts. (Choice A) When redness, warmth, and severe tenderness accompany bursal swelling, an aspiration should be done to rule out septic bursitis. This patient does not have these acute inflammatory changes. (Choice B) Rigid knee immobilizers are indicated for short-term management of patella fracture or rupture of the quadriceps/patellar ligament complex. Immobilization of the knee is not indicated in PAB because it may promote muscular atrophy and increase the risk of additional injury. (Choice C) MRI is useful in diagnosing ligament or meniscus tears, which typically present with significant knee pain and effusion following trauma. Stress fractures can be missed by x-ray and can be diagnosed with MRI, especially in early stages (ie, first 1-2 weeks). However, this patient has had symptoms for 3 weeks; stress fracture significant enough to cause localized swelling would have been identified on the x-ray. (Choice E) Serum inflammatory markers can be useful when rheumatologic disease (eg, gout) or infection is suspected to be the cause of the bursal swelling. Redness, warmth, and significant pain typically accompany bursal swelling. Educational objective: Pes anserine bursitis presents as a swelling over the upper medial tibial region. It is typically caused by overuse and poor knee mechanics. Treatment includes quadriceps and hamstring strengthening exercises to optimize strength, flexibility, and stability of the knees. References: Pes anserine bursitis. (http://www.ncbi.nlm.nih.gov/pubmed/30422536)

A 38-Year-Old Woman Comes to the Office Due to Left