title: Subchondral impaction fractures of the non-weight-bearing portion of the lateral femoral condyle.
abstract: OBJECTIVE
  To document the first report of intra-articular, non-weight-bearing, impaction fractures of the lateral femoral condyle.
  
  
  METHODS
  Institutional Review Board and Regional Ethics Committee approval for this study was obtained and patient informed consent deemed unnecessary. We prospectively documented all potential cases of non-weight-bearing posterior subchondral impaction fractures of the femoral condyles diagnosed on magnetic resonance imaging (MRI) of the knee performed at our institution between January 2006 and December 2011. The cases were reviewed and discussed by three experienced musculoskeletal radiologists and only cases satisfying pre-defined MRI criteria were included.
  
  
  RESULTS
  Sixteen cases of intra-articular impaction fractures in a posterior, non-weight-bearing area of the lateral femoral condyle were diagnosed in patients with a mean age of 40. Eight were associated with recreational sports activities and 4 with repeated kneeling. There were no fractures documented in the non-weight-bearing aspect of the medial femoral condyles. Proposed underlying mechanisms for development of this type of fracture are presented.
  
  
  CONCLUSIONS
  Awareness, along with a high level of suspicion, that non-specific knee pain, especially in patients involved in athletic activities, could be due to intra-articular impaction fractures of the non-weight-bearing posterior aspect of the lateral femoral condyle is essential and MRI is the mainstay of diagnosis.
authors.affiliation: Radiology Department, Robert Jones and Agnes Hunt Orthopaedic and District Hospitals NHS Trust, Gobowen, Oswestry, Shropshire, SY10 7AG, UK.
authors.forename: Ruben
authors.initials: R
authors.lastname: Depasquale
authors.forename: Anastasia
authors.initials: A
authors.lastname: Fotiadou
authors.forename: Dalavaye Suresh
authors.initials: DS
authors.lastname: Kumar
authors.forename: Radhesh
authors.initials: R
authors.lastname: Lalam
authors.forename: Bernhard
authors.initials: B
authors.lastname: Tins
authors.forename: Prudencia N M
authors.initials: PN
authors.lastname: Tyrrell
authors.forename: Jaspreet
authors.initials: J
authors.lastname: Singh
authors.forename: Victor N
authors.initials: VN
authors.lastname: Cassar-Pullicino
mesh_terms: D000328:Adult; D005260:Female; D005264:Femoral Fractures / Q000175:diagnosis* / Q000453:epidemiology*; D050815:Fractures, Compression / Q000175:diagnosis* / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D006113:United Kingdom / Q000453:epidemiology; D016474:Weight-Bearing