title: Regional migratory osteoporosis in the knee: MRI findings in 22 patients and review of the literature.
abstract: OBJECTIVE
  Acute non-traumatic bone marrow edema (BME) in the knee is a common clinical problem. The aim of the present study is to present the MR imaging findings of the uncommon transient migratory pattern of this syndrome.
  
  
  METHODS
  Twenty-two patients (21 men, 1 woman, age range 35-73 years, mean 49.4+/-7.6) who presented with pain in the knee joint (ranging from 2 weeks to 6 months) and BME in the MR imaging examination, were included in the study. In all cases, the knee joint BME was either preceded or followed by another site of BME in the same or another joint. All patients were studied with plain X-rays and MR imaging at presentation and with MR imaging after resolution of symptoms.
  
  
  RESULTS
  The eight patients with initial involvement in the knee showed migration either intra-articularly (5), or/and in the contralateral knee (2) and only 1 case showed migration to the ipsilateral hip joint. In two patients the BME shifted from the hip first to the foot and then to the knee. The median migration period was 4 months for the second involvement in all patients and 3 months for the third involvement (10 patients).
  
  
  CONCLUSIONS
  The present study reports the largest series of patients with regional migratory osteoporosis involving the knee. In most of the cases, shifting of BME remains in the joint or moves to the contralateral knee. In only one case the BME shifted from the knee elsewhere. All lesions were transient.
authors: Department of Radiology, University of Crete, Heraklion 711 10, Greece. apolsen@yahoo.com
authors: Apostolos H
authors: AH
authors: Karantanas
authors: Ioannis
authors: I
authors: Nikolakopoulos
authors: Anastasios V
authors: AV
authors: Korompilias
authors: Eleni
authors: E
authors: Apostolaki
authors: Nicolaos
authors: N
authors: Skoulikaris
authors: Eleni
authors: E
authors: Eracleous
mesh_terms: D000328:Adult; D000368:Aged; D001855:Bone Marrow Diseases / Q000175:diagnosis*; D004487:Edema / Q000175:diagnosis*; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis / Q000175:diagnosis*; D013577:Syndrome