title: Analysis of bone demineralization due to the use of exoprosthesis by comparing Young's modulus of the femur in unilateral transfemoral amputees.
abstract: BACKGROUND
  There is a relation between Hounsfield units obtained from computed tomography (CT) scans and bone density. The density of the bones can be used to establish its mechanical properties and therefore to assess the bone mechanical condition using CT images.
  
  
  OBJECTIVE
  To identify the effect of the transfemoral amputation and the use of external lower limb prosthesis in the bone properties, by comparing Young's modulus.
  
  
  METHODS
  Young's modulus comparison.
  
  
  METHODS
  Comparison of bone density between the healthy femur and the amputated bone of 20 unilateral transfemoral amputees was done by generating three histograms of the Hounsfield units at different parts of the femur. The histograms were created based on images obtained by CT and the Hounsfield units were translated to Young's modulus to establish the comparison.
  
  
  RESULTS
  The results show a significant difference (p-value <0.05) between the mean value of Young's modulus of healthy and amputated bone.
  
  
  CONCLUSIONS
  There is clearly a direct association between the use of external prosthesis and the bone demineralization due the stress shielding phenomenon. The Young's modulus comparison using information from CT images can be a suitable tool to analyze the bone demineralization due to the use of exoprosthesis.
authors: National University of Colombia, Medellín, Colombia. jframirp@unal.edu.co
authors: Juan Fernando
authors: JF
authors: Ramírez
authors: Jésica Andrea
authors: JA
authors: Isaza
authors: Isabela
authors: I
authors: Mariaka
authors: Jaime Andrés
authors: JA
authors: Vélez
mesh_terms: D000328:Adult; D000368:Aged; D000674:Amputees; D001186:Artificial Limbs / Q000009:adverse effects*; D001696:Biomechanical Phenomena; D018488:Bone Demineralization, Pathologic / Q000209:etiology* / Q000503:physiopathology; D015519:Bone Density / Q000502:physiology*; D055119:Elastic Modulus / Q000502:physiology*; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging / Q000502:physiology* / Q000601:surgery*; D020342:Finite Element Analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D013314:Stress, Mechanical; D014057:Tomography, X-Ray Computed; D016474:Weight-Bearing