Patella dislocation

Revision as of 16:03, 29 December 2014 by Ostermayer (talk | contribs)

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)