Exam

Knee Effusion

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Knee Effusion, Knee Swelling

  • See Also
  1. Knee Exam
  2. Knee Effusion Causes
  3. Acute Monoarthritis
  4. Synovial Fluid
  • Causes
  1. Intraarticular Swelling
    1. See Knee Effusion Causes
  2. Extrarticular Swelling
    1. Anterior: Prepatellar or infrapatellar Bursitis
    2. Posterior: Popliteal Cyst
    3. Medial: Pes Anserine Bursitis
    4. Lateral: Iliotibial Band Syndrome
  • Signs
  1. Swollen knee assumes 15-25 degree resting position
  2. Landmarks of anterior knee obscured by fluid
  3. Knee Bulge Sign
  4. Ballottable Patella Sign
  1. See Monoarthritis or Polyarthritis
  2. See Synovial Fluid
  3. Indications
    1. Arthrocentesis is key to exclude Septic Joint in Acute Monoarthritis
    2. Large, painful Knee Effusion of unclear etiology
  4. Simple clear transudative fluid
    1. Knee sprain
    2. Chronic meniscal tear
  5. Hemarthrosis (Bloody effusion)
    1. Anterior Cruciate Ligament Tear
    2. Osteochondral Fracture (Tibial Plateau Fracture)
    3. Acute meniscal tear
  6. Pustular Drainage
    1. Septic Joint
  • References
  1. Johnson (2000) Am Fam Physician 61(8): 2391-400 [PubMed]
  2. Pendergraph (2026) Am Fam Physician 114(1): 49-62 [PubMed]