title: Spontaneous osteonecrosis of the lateral femoral condyle of the knee: a report of 11 cases.
abstract: BACKGROUND
  Spontaneous osteonecrosis (SON) of the lateral femoral condyle of the knee joint is very rare and there have been only a few articles about this condition.
  
  
  METHODS
  We reviewed data for 11 patients (7 men, 4 women) with unusual SON of the lateral femoral condyle of the knee. The average age of patients at onset was 61.9 years (range 47-76 years). No patient had underlying disease or had undergone steroid therapy, although one underwent lateral meniscectomy.
  
  
  RESULTS
  According to Aglietti's radiographic classification, three patients had stage 1 disease, two had stage 2 disease, three had stage 3 disease, one had stage 4 disease, and two had stage 5 at first examination. The average alignment of affected limbs on standing was 5.9 degrees valgus (range 0 degrees -11 degrees ). Although the osteonecrotic lesion was seen on the lateral side, the mechanical axis passed the medial compartment in three patients. Six patients were treated conservatively and the remaining five required surgery, which consisted of lateral unicompartmental knee arthroplasties.
  
  
  CONCLUSIONS
  The pathology of the necrosis of the lateral femoral condyle was considered to be different from that of the medial femoral condyle regarding clinical features, limb alignment, and radiographic findings.
authors.affiliation: Fukuoka Orthopaedic Hospital, 2-10-50, Yanagouchi Minami-ku, Fukuoka 815-0063, Japan. ohdera@jcom.home.ne.jp
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Ohdera
authors.forename: Satoshi
authors.initials: S
authors.lastname: Miyagi
authors.forename: Masami
authors.initials: M
authors.lastname: Tokunaga
authors.forename: Eiji
authors.initials: E
authors.lastname: Yoshimoto
authors.forename: Shusaku
authors.initials: S
authors.lastname: Matsuda
authors.forename: Hiroya
authors.initials: H
authors.lastname: Ikari
mesh_terms: D000368:Aged; D005260:Female; D005269:Femur / Q000473:pathology*; D006801:Humans; D007717:Knee / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010020:Osteonecrosis / Q000145:classification / Q000000981:diagnostic imaging / Q000473:pathology*; D011859:Radiography; D012189:Retrospective Studies