Patella dislocation: Difference between revisions

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==Background==
==Background==
*extended knee with externally rotated foot and twisting motion
*Occurs with trauma to an extended knee with externally rotated foot and twisting motion<ref>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</ref>
*acute: in traumatic injury, equal genders
*Acute: in traumatic injury, equal gender<ref name="epi">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</ref>
*chronic: women/teenage girls
*Chronic: women/teenage girls<ref name="epi></ref>
*commonly lateral displacement and unable to extend knee
*Commonly lateral displacement and unable to extend knee
[[File:Patellar dislocation.jpg|thumb|patella dislocates laterally]]
[[File:Patellar dislocation.jpg|thumb|patella dislocates laterally]]
[[File:Patellar Dislocation Relocation.jpg|thumb|Relocation with lateral pressure on dislocated patella]]
[[File:Patellar Dislocation Relocation.jpg|thumb|Relocation with lateral pressure on dislocated patella]]
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==Diagnosis==
==Diagnosis==
*Patella is usually displaced laterally; knee is held in flexion
*Patella is usually displaced laterally; knee is held in flexion
*acute: often with large hemarthrosis
*Acute: often with large hemarthrosis
*chronic: little to no swelling
*Chronic: little to no swelling


==Work-Up==
==Work-Up==
*xray if traumatic mechanism to r/o fracture
*Xray if traumatic mechanism to rule out fracture
*do not need xay prior to reduction if chronic
*Do not need xay prior to reduction if chronic


*Post-reduction x-ray: confirm reduction, eval for fractures and loose bodies (avulsions, misalignment, etc)<ref>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</ref>
*Post-reduction x-ray: confirm reduction, eval for fractures and loose bodies (avulsions, misalignment, etc)<ref>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</ref>
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==Source==
==Source==
*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
<references/>
*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
 
*AAOS Comprehensive Orthopaedic Review, Jay R. Leiberman. Published by American Academy of Orthopaedic Surgeons, Rosemont IL. Copyright 2009


==See Also==
==See Also==

Revision as of 16:03, 29 December 2014

Background

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

Diagnosis

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

Work-Up

  • 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

Treatment

  • Reduce; do not need x-rays prior to reduction
    • Extend knee and slide patella back into place
    • Knee immobilizer, NSAIDs, partial weight-bearing
    • Orthopedic followup within 1-2wks
  • Unable to Reduce or Loose bodies/fracture on post-reduction imaging
  • Obtain immediate ortho consult

Source

  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)