I. Indication

  1. Evaluation for large Knee Joint effusion

II. Technique

  1. Patient lies supine on table
  2. Examiner forces fluid from suprapatellar pouch
    1. Firmly grasp just above Patella with one hand
    2. Forces Joint Fluid between Patella and femur
  3. Examiner pushes Patella downward into femur with 2-3 fingers
    1. Use a quick sharp motion in pushing the Patella down
    2. Assess for palpable click on Patella striking femur

III. Interpretation: Positive test suggests large effusion

  1. Large Knee Joint effusion: Palpable click present as Patella strikes the trochlea
  2. No joint effusion (normal): no click palpated

IV. References

  1. Bates (1991) Physical Exam, Lippincott
  2. Kastelein (2009) Arch Phys Med Rehabil 90(1): 82-86 [PubMed] (or open in [QxMD Read])

Images: Related links to external sites (from Google)

Ontology: Patellar tap (C0231756)

Concepts Sign or Symptom (T184)
SnomedCT 56020001
Dutch zwevende patella
French Rotule flottante
German tanzende Patella
Italian Rotula fluttuante
Portuguese Rótula flutuante
Spanish Rótula flotante, percusión rotuliana, percusión rotuliana (hallazgo), rótula flotante, clic rotuliano, peloteo rotuliano (hallazgo), peloteo rotuliano, chasquido rotuliano
Japanese 膝蓋跳動, シツガイチョウドウ
English knee patella ballottement, patellar ballottement (physical finding), patellar ballottement, floating patella, patellar tapping, patellar tap, Floating patella, Patellar ballottement, Patellar tap, Patellar click, Patellar tap (finding)
Czech Plovoucí čéška
Hungarian Mobilis patella