Best Practice Case Studies-Case 138 Asset 2 Knee Pain

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This article outlines the initial primary care evaluation of undifferentiated knee pain in adults and adolescents. Knee pain is common and increasing, so clinicians should first rule out urgent conditions and decide when referral is needed. Key history elements include age, pain location, onset, duration, quality, swelling, trauma mechanism, mechanical symptoms, systemic symptoms, and prior medical or surgical history.<br /><br />Urgent referral is recommended for severe pain with immediate swelling and inability to bear weight after acute trauma, suggesting fracture, dislocation, or ligament/tendon rupture. Fever, erythema, swelling, and limited range of motion raise concern for joint infection.<br /><br />Pain location helps narrow the diagnosis:<br />- Anterior pain suggests patellar, patellar tendon, or extensor mechanism problems such as patellofemoral pain syndrome, tendinopathy, Osgood-Schlatter disease, or prepatellar bursitis.<br />- Medial or lateral pain may indicate meniscal injury, collateral ligament injury, pes anserine bursitis, or slipped capital femoral epiphysis in adolescents.<br />- Posterior pain may reflect a Baker cyst, PCL injury, meniscal injury, or hamstring tendinopathy.<br />- Diffuse chronic pain in older adults often suggests osteoarthritis; acute atraumatic diffuse pain may indicate infection, gout, or rheumatoid arthritis.<br /><br />Mechanical symptoms like locking, catching, or buckling suggest internal derangement, especially meniscal or ligament injury. Rapid swelling after injury points to ligament rupture, fracture, or patellar dislocation; swelling developing over hours to days suggests meniscal tear.<br /><br />Physical examination should include inspection, palpation, range of motion, strength, neurovascular assessment, and provocative tests. Useful maneuvers include Lachman, anterior drawer, pivot shift, posterior drawer, Thessaly, McMurray, valgus/varus stress, and patellar apprehension tests.<br /><br />Radiography should be reserved for chronic pain or acute trauma meeting evidence-based criteria such as the Ottawa or Pittsburgh Knee Rules. Ultrasound can assess effusions, Baker cysts, and superficial structures. MRI is generally reserved for suspected surgical problems or persistent symptoms after conservative treatment. Laboratory tests and arthrocentesis help confirm infection, crystal disease, or inflammatory arthritis when indicated.

Meta Tag

Edition 4th Edition

Related Case 4th Edition, Case 138

Topic Knee

Keywords

knee pain

primary care evaluation

urgent referral

mechanical symptoms

meniscal injury

ligament injury

osteoarthritis

joint infection

physical examination

imaging criteria

4th Edition

4th Edition, Case 138

Knee