title: Clinical outcome of edema-like bone marrow abnormalities of the foot.
abstract: OBJECTIVE
  To evaluate the clinical outcome of edema-like bone marrow abnormalities seen on magnetic resonance (MR) images of the foot when their cause is unknown.
  
  
  METHODS
  The clinical outcome of 31 patients (15 female patients, 16 male patients; mean age, 51; range, 10-79 years) with edema-like bone marrow abnormalities on MR images of the foot was determined. The relevance of three different edema patterns was compared: (a) exclusively ill-defined edema-like zones, (b) edema-like zones plus well-defined necrosis-like zones, and (c) edema-like zones plus linear structures indicating possible fractures. The different edema patterns were compared with persistence of pain.
  
  
  RESULTS
  Fifty-four percent of all patients had pain persisting after 1 year, as calculated with the Kaplan-Meier method. The duration of pain in the various subgroups varied significantly (P =.049, log-rank test). The subgroup of patients with a well-defined necrosis-like zone had substantially longer-lasting pain than those with edema-like abnormalities only (n = 16) (P =.065). Only one of seven patients with a well-defined necrosis-like zone (n = 7) was pain free after 1 year. Conversely, patients with possible stress fracture (n = 8) had shorter pain compared with those with edema-like abnormalities only (P =.036); six of eight patients were pain free after 1 year.
  
  
  CONCLUSIONS
  Edema-like bone marrow abnormalities of the foot predict long-lasting pain. Analysis of the image patterns of such abnormalities allows prediction of the clinical outcome to a certain degree.
authors.affiliation: Department of Radiology, Orthopedic University Hospital Balgrist, Forchstrasse 340, CH-8008 Zurich, Switzerland. marco.zanetti@balgrist.ch
authors.forename: Marco
authors.initials: M
authors.lastname: Zanetti
authors.forename: Christian Luzius
authors.initials: CL
authors.lastname: Steiner
authors.forename: Burkhardt
authors.initials: B
authors.lastname: Seifert
authors.forename: Juerg
authors.initials: J
authors.lastname: Hodler
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001853:Bone Marrow / Q000473:pathology*; D001855:Bone Marrow Diseases / Q000150:complications / Q000175:diagnosis* / Q000473:pathology; D002648:Child; D004487:Edema / Q000209:etiology / Q000473:pathology*; D005260:Female; D005528:Foot / Q000473:pathology*; D015775:Fractures, Stress / Q000150:complications / Q000175:diagnosis; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009336:Necrosis; D010146:Pain / Q000209:etiology; D016016:Proportional Hazards Models; D018709:Statistics, Nonparametric