Patella dislocation: Difference between revisions

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**Knee immobilizer, NSAIDs, partial weight-bearing
**Knee immobilizer, NSAIDs, partial weight-bearing
**Orthopedic follow-up within 1-2wks
**Orthopedic follow-up within 1-2wks
*Unable to Reduce or Loose bodies/fracture on post-reduction imaging
*Unable to reduce or loose bodies/fracture on post-reduction imaging
*Obtain immediate ortho consult
**Obtain immediate ortho consult


==References==
==References==

Revision as of 18:19, 18 April 2017

Background

  • Occurs with trauma to an extended knee with externally rotated foot and twisting motion[1]
  • Acute: in traumatic injury, occurs equally in men/women [2]
  • Chronic: women/teenage girls[2]
  • Commonly lateral displacement and unable to extend knee
patella dislocates laterally
Relocation with lateral pressure on dislocated patella

Clinical Features

  • Patella is usually displaced laterally; knee is held in flexion
  • Acute: often with large hemarthrosis
  • Chronic: little to no swelling

Differential Diagnosis

Knee diagnoses

Acute knee injury

Nontraumatic/Subacute

Evaluation

  • Xray if traumatic mechanism to rule out fracture
  • Do not need xay prior to reduction if chronic
  • Post-reduction x-ray: confirm reduction, eval for fractures and loose bodies (avulsions, misalignment, etc)[3]
  • Common associated fractures
    • Medial patella facet
    • Lateral femoral condyle

Management

  • Reduce; do not need x-rays prior to reduction
    • Mild flexion of hip (20-30 degrees) to relax quadriceps
    • Extend and slightly hyperextend the knee and slide patella back into place
    • Knee immobilizer, NSAIDs, partial weight-bearing
    • Orthopedic follow-up within 1-2wks
  • Unable to reduce or loose bodies/fracture on post-reduction imaging
    • Obtain immediate ortho consult

References

  1. Review of Orthopaedics, 6th Edition, Mark D. Miller MD, Stephen R. Thompson MBBS MEd FRCSC, Jennifer Hart MPAS PA-C ATC, an imprint of Elsevier, Philadelphia, Copyright 2012
  2. 2.0 2.1 Fithian DC, Paxton EW, Stone ML, Silva P, Davis DK, Elias DA, White LM. Epidemiology and natural history of acute patellar dislocation. AJSM 2004;32:1114-1121
  3. Krause E A. et al. Pediatric lateral patellar dislocation: is there a role for plain radiography in the emergency department? J Emerg Med. 2013 Jun;44(6):1126-31

See Also

Knee (Main)