Patellar Tap Test | Knee Exam - MedSchool
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Knee Exam
 
 
Knee Exam
The patellar tap test assesses for an effusion of the knee joint; in a patient with a significant effusion there will be fluid behind the patella, and tapping the knee will result in a satisfying clunk as the patella makes contact with the femur posteriorly.
 

Patellar Tap Test

 
 

Overview

  • The patellar tap test assesses for an effusion of the knee joint; in a patient with a significant effusion there will be fluid behind the patella, and tapping the knee will result in a satisfying clunk as the patella makes contact with the femur posteriorly.
    • How to Perform

    • Using 2-3 fingers, sharply tap onto the patient's patella.
    • Abnormal If

    • A palpable ‘clunk' occurs, when the patella makes contact with the trochlea.
    • Causes of Knee Effusion

    • Trauma - ligament tear, menisceal tear, fracture, patellar dislocation
    • Arthritis - osteoarthritis, psoriatic arthritis, reactive arthritis, IBD-related arthritis, gout, pseudogout
    • Infection - septic arthritis, tuberculosis, Lyme disease, syphilis
    • Blood - haemarthrosis
    • Malignancy - osteosarcoma
Last updated on November 25th, 2019
 
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Read More...

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