title: MRI diagnosis of occult hip fractures.
abstract: BACKGROUND
  Most fractures of the proximal femur are easily diagnosed by conventional radiography. When the images are judged to be negative or equivocal and a clinical suspicion of fracture persists, another approach is to use magnetic resonance imaging (MRI) to help reach a diagnosis.
  
  
  METHODS
  In a prospective study running from November 1998 to December 2001, we registered all patients being examined by MRI who had had a negative or equivocal radiograph and where there was continued clinical suspicion of hip fracture.
  
  
  RESULTS
  100 consecutive patients (67 women) were included, with an average age of 80 (37-100) years. The MRI examinations corresponded to 4% of the 2,350 patients admitted with hip trauma during the study period. 46 patients had a femoral neck or intertrochanteric fracture on MRI. 27 patients had other fractures. 18 had other findings on MRI, and 10 were interpreted as being negative, although one of these was a false negative. In a separate interobserver analysis, two experienced radiologists agreed on the diagnoses in 19/23 cases (kappa value 0.78). They agreed with a less experienced radiologist in 17/23 and 19/23 cases, respectively (kappa values 0.66 and 0.76).
  
  
  CONCLUSIONS
  MRI is a useful tool for demonstration of occult hip fractures. In the absence of a hip fracture, another explanation for the patient's pain and disability will often be given.
authors.affiliation: Orthopedic Center, Musculoskeletal Division, Ullevål University Hospital, Oslo, Norway. frede.frihagen@uus.no
authors.forename: Frede
authors.initials: F
authors.lastname: Frihagen
authors.forename: Lars
authors.initials: L
authors.lastname: Nordsletten
authors.forename: Rana
authors.initials: R
authors.lastname: Tariq
authors.forename: Jan Erik
authors.initials: JE
authors.lastname: Madsen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005265:Femoral Neck Fractures / Q000175:diagnosis* / Q000000981:diagnostic imaging; D006620:Hip Fractures / Q000175:diagnosis* / Q000000981:diagnostic imaging; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011446:Prospective Studies; D011859:Radiography; D012680:Sensitivity and Specificity