Knee Pain/Swelling
Primary care physicians, rheumatologists, and orthopedists frequently encounter complaints about the knee. Because the range of illnesses affecting the knee varies greatly, a thorough history and physical exam are essential. Once a differential diagnosis is compiled, plain films of the joint are usually indicated.
Differential Diagnosis
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Degenerative joint disease (osteoarthritis)
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Ligamentous injury
–ACL: Positive Lachman (more sensitive) and anterior drawer test
–PCL: Positive thumb sign (more sensitive) and posterior drawer test
–MCL: Pain and/or increased laxity with valgus stress
–LCL: Pain and/or increased laxity with varus stress -
Meniscus tear
–Patient may complain of pain and locking; positive McMurray circumduction test
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Patellofemoral syndrome
- Iliotibial band syndrome
–Pain along the lateral aspect of the knee accompanied by a palpable or audible snapping
–Occurs almost exclusively in runners
- Pes anserine bursitis
–Patients complain of pain along the medial aspect of the knee (at pes anserinus insertion)
–Caused by repetitive movement that creates an inflammatory response
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Joint effusion
–May be secondary to osteoarthritis, inflammatory arthritis, ligament injury, gout, pseudogout, or infection -
Joint infection (septic joint)
–Staphylococcus aureus is most common
–Neisseria gonorrhoeae is common in
adolescents and young adults
–Salmonella is common in sickle cell patients
–Haemophilus influenzae is common in children -
Osteochondritis dissecans (OCD)
–Osteonecrosis of subchondral bone
–Most commonly seen in the knee
–Patient reports a gradual onset of pain
–Exam reveals tenderness of the affected
area with manipulation
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In the pediatric population, consider Osgood-Schlatter disease, physeal injury, and discoid meniscus
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Hip or foot/ankle disease with referred pain to the knee
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Malignancy
-
Osteomyelitis
Workup and Diagnosis
- History and physical examination are often diagnostic
–Inspect the patient's gait for limitations of motion or other abnormalities
–Visually assess symmetry between the knees: Note
swelling, deformity, erythema, and muscle atrophy
–Palpate: Note tenderness, warmth, and crepitus
–“Milk the joint” to elicit an effusion
–Test for range of motion (active and passive)
–Perform McMurray circumduction test and ligament
testing (e.g., Lachman test, anterior/posterior drawer tests, thumb sign, varus/valgus stress tests)
-
X-rays are often indicated
–AP, lateral, and merchant or sunrise films of both knees
–When possible, also obtain weight-bearing A/P films
–Merchant and sunrise X-rays of the patella are used to
evaluate alignment and injury to the patella
–On occasion, tunnel views of the knee are useful (e.g., for OCD)
-
Joint aspiration should be performed in patients with joint effusions; fluid analysis includes cell count with differential, crystals, Gram stain, and culture
-
MRI may not be necessary during initial evaluation, but may help with confirmation of specific injuries and surgical planning (e.g., PCL tear, meniscus tear, OCD)
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Bone scan may be used to evaluate malignancy or infection
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In some cases, blood work may include CBC, ESR, C-reactive protein, alkaline phosphatase, and uric acid
Treatment
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Conservative therapy is usually sufficient
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OA: Lifestyle modification (e.g., weight loss, exercise); anti-inflammatory medications (e.g., NSAIDs, COX-2 inhibitors); joint injections may benefit some people (e.g. corticosteroids, hyaluronic acid); surgery may be necessary for those who fail conservative treatment
-
Ligamentous injuries: ACL injuries may require definitive treatment via reconstructive surgery; PCL injuries are usually not repaired
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Meniscal tears may require repair or excision; however, most meniscus injuries are asymptomatic or mild and require no treatment
-
Patellofemoral syndrome often responds to physical therapy and exercise
-
Joint infection (e.g., septic arthritis) is a surgical emergency; irrigation, debridement, and antibiotic administration should be considered
Book Source Details
- Book Title: In a Page: Signs and Symptoms
- Author(s): Scott Kahan, Ellen G. Smith
- Year of Publication: 2004
- Copyright Details: In a Page: Signs and Symptoms, Copyright © 2004 Lippincott Williams & Wilkins.
Other Book Chapters Related to Knee swelling
Read excerpts from these other book chapters related to Knee swelling:
Medical Books Excerpts
- KNEE PAIN
- "Algorithmic Diagnosis of Symptoms and Signs" (2003)
- [ read ]
- Knee Pain
- "In A Page: Pediatric Signs and Symptoms" (2007)
- [ read ]
- Knee Pain
- "The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter" (2000)
- [ read ]
Copyright Details: In a Page: Signs and Symptoms, Copyright © 2008 Williams & Wilkins.
More About Causes of Knee swelling
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More About This Book:
Title: In a Page: Signs and Symptoms
Authors: Scott Kahan, Ellen G. Smith
Publisher: Lippincott Williams & Wilkins
Copyright: 2004
ISBN: 1-4051-0368-X
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» Next page: Knee Pain (In A Page: Pediatric Signs and Symptoms)
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