title: Radiographic features of multifocal endosteal thickening of the femur in patients on long-term bisphosphonate therapy.
abstract: OBJECTIVE
  To describe the characteristics of multifocal endosteal thickening in patients on bisphosphonate therapy.
  
  
  METHODS
  A retrospective study of 68 patients with atypical femoral fractures (as defined by ASBMR) whilst on bisphosphonate therapy was performed. Femoral radiographs were assessed for: focal endosteal thickening, number of lesions, lesion location, femoral bowing, periosteal beak and black line. Medical records were reviewed to obtain relevant clinical data.
  
  
  RESULTS
  Forty-eight lesions with multifocal endosteal thickening were detected in seven patients (2 unilateral, 5 bilateral), affecting 11.8 % of femora. Location was mainly diaphyseal (95.8 %), upper (10.4 %), middle (58.3 %) and lower femur (31.3 %), involving the lateral (85.4 %), anterior (6.3 %), anterolateral (2.1 %) and posterior cortices (6.3 %). Femoral bowing was present in 85.7 %. Associated findings of a periosteal beak and/or a black line, seen in 14.6 %, were associated with increased fracture risk (100.0 % sensitivity, 93.2 % specificity).
  
  
  CONCLUSIONS
  Multifocal endosteal thickening is a new finding seen in patients with low bone mineral density on bisphosphonate therapy. They are rare, frequently bilateral, predominantly diaphyseal in location involving the lateral cortex and often associated with bowing. Caution is advised when seen in association with periosteal beak and/or black line because of a high rate of progression to complete fracture.
authors: Department of Diagnostic Radiology, Singapore General Hospital, Outram Road, Singapore, 169608, Singapore. chandra.mohan@sgh.com.sg
authors: P Chandra
authors: PC
authors: Mohan
authors: Tet Sen
authors: TS
authors: Howe
authors: Joyce S B
authors: JS
authors: Koh
authors: Meng Ai
authors: MA
authors: Png
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D015519:Bone Density / Q000187:drug effects; D050071:Bone Density Conservation Agents / Q000009:adverse effects*; D001851:Bone Diseases, Metabolic / Q000188:drug therapy*; D015897:Comorbidity; D004164:Diphosphonates / Q000009:adverse effects*; D005260:Female; D005264:Femoral Fractures / Q000139:chemically induced* / Q000000981:diagnostic imaging*; D006801:Humans; D008875:Middle Aged; D010024:Osteoporosis / Q000188:drug therapy*; D011859:Radiography; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
chemical_list: D015415:Biomarkers; D050071:Bone Density Conservation Agents; D004164:Diphosphonates