title: Subchondral insufficiency fracture of the femoral head may be associated with hip dysplasia: a pilot study.
abstract: BACKGROUND
  Subchondral insufficiency fracture of the femoral head occurs mainly in elderly patients with osteoporosis. Spontaneous resolution is observed after nonoperative treatment in some patients whereas other show progressive joint destruction requiring THA. Several studies report the occurrence of subchondral insufficiency fracture of the femoral head in dysplastic hips.
  
  
  OBJECTIVE
  We asked whether the extent of hip dysplasia or osteoporosis was greater in patients with subchondral insufficiency fracture of the femoral head than in normal control subjects.
  
  
  METHODS
  We compared the clinical and imaging findings of 13 patients with subchondral insufficiency fractures of the femoral head and 12 patients scheduled for TKA with asymptomatic hips. Age, gender, and body mass index were comparable in the two groups.
  
  
  RESULTS
  Higher mean Sharp angles, lower acetabular head indices, lower center-edge angles, and higher acetabular roof angles in patients with subchondral insufficiency fracture of the femoral head than in those with asymptomatic hips suggested a greater degree of hip dysplasia. Bone mineral density and serum levels of Type I collagen cross-linked N-telopeptide and bone alkaline phosphatase were similar in the two groups.
  
  
  CONCLUSIONS
  We speculate an excessive amount of stress on the acetabular edge from dysplasia may be associated with the occurrence of subchondral insufficiency fracture of the femoral head.
authors.affiliation: Department of Orthopaedic Surgery, Kyushu Rosai Hospital, 1-3-1 Kuzuharatakamatsu, Kokuraminami-ku, Kitakyushu 800-0296, Japan.
authors.forename: Kohei
authors.initials: K
authors.lastname: Ishihara
authors.forename: Keita
authors.initials: K
authors.lastname: Miyanishi
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Ihara
authors.forename: Seiya
authors.initials: S
authors.lastname: Jingushi
authors.forename: Takehiko
authors.initials: T
authors.lastname: Torisu
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000469:Alkaline Phosphatase / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism; D015992:Body Mass Index; D015519:Bone Density; D024042:Collagen Type I / Q000097:blood; D003937:Diagnosis, Differential; D005260:Female; D005265:Femoral Neck Fractures / Q000175:diagnosis / Q000209:etiology* / Q000378:metabolism; D005270:Femur Head / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology; D005500:Follow-Up Studies; D015775:Fractures, Stress / Q000175:diagnosis / Q000209:etiology* / Q000378:metabolism; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010009:Osteochondrodysplasias / Q000150:complications* / Q000175:diagnosis / Q000378:metabolism; D010024:Osteoporosis / Q000150:complications* / Q000175:diagnosis / Q000378:metabolism; D010455:Peptides / Q000097:blood; D010865:Pilot Projects; D011859:Radiography; D012189:Retrospective Studies
chemical_list: D015415:Biomarkers; D024042:Collagen Type I; D010455:Peptides; C052929:collagen type I trimeric cross-linked peptide; D000469:Alkaline Phosphatase