title: A clinicopathologic study of transient osteoporosis of the hip.
abstract: OBJECTIVE
  It has been proposed that transient osteoporosis of the hip (TOH) may represent the early reversible phase of osteonecrosis of the femoral head (ON). The purpose of this study was to investigate the clinicopathologic characteristics of three cases of TOH.
  
  
  METHODS
  A bone biopsy was performed on three patients who had been diagnosed as having TOH based on the clinical course, radiograph, bone scintigram, and MR images. The biopsy specimens were studied histopathologically by light and electron microscopy.
  
  
  RESULTS
  The most characteristic feature of TOH was focal areas of thin and disconnected bone trabeculae covered by osteoid seams and active osteoblasts. The surrounding bone marrow tissue showed edematous changes and mild fibrosis, frequently associated with vascular congestion and/or interstitial hemorrhage. No osteonecrotic region was observed in either the bone trabeculae or the bone marrow tissue. All patients have improved clinically and in the 3.5-9 years of follow-up have shown no evidence of ON.
  
  
  CONCLUSIONS
  This study supports the concept that transient osteoporosis of the hip is a distinct entity.
authors.affiliation: Department of Orthopaedic Surgery, Faculty of Medicine, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Yamamoto
authors.forename: T
authors.initials: T
authors.lastname: Kubo
authors.forename: Y
authors.initials: Y
authors.lastname: Hirasawa
authors.forename: Y
authors.initials: Y
authors.lastname: Noguchi
authors.forename: Y
authors.initials: Y
authors.lastname: Iwamoto
authors.forename: K
authors.initials: K
authors.lastname: Sueishi
mesh_terms: D000328:Adult; D001175:Arthrography; D001706:Biopsy; D001853:Bone Marrow / Q000000981:diagnostic imaging / Q000473:pathology; D001842:Bone and Bones / Q000000981:diagnostic imaging / Q000648:ultrastructure; D003937:Diagnosis, Differential; D005260:Female; D005271:Femur Head Necrosis / Q000175:diagnosis; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000473:pathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D010024:Osteoporosis / Q000175:diagnosis*; D011877:Radionuclide Imaging