title: Long-term stress distribution patterns of the ankle joint in varus knee alignment assessed by computed tomography osteoabsorptiometry.
abstract: OBJECTIVE
  The stress distribution of an ankle under various physiological conditions is important for long-term survival of total ankle arthroplasty. The aim of this study was to measure subchondral bone density across the distal tibial joint surface in patients with malalignment/instability of the lower limb.
  
  
  METHODS
  We evaluated subchondral bone density across the distal tibial joint in patients with malalignment/instability of the knee by computed tomography (CT) osteoabsorptiometry from ten ankles as controls and from 27 ankles with varus deformity/instability of the knee. The quantitative analysis focused on the location of the high-density area at the articular surface, to determine the resultant long-term stress on the ankle joint.
  
  
  RESULTS
  The area of maximum density of subchondral bone was located in the medial part in all subjects. The pattern of maximum density in the anterolateral area showed stepwise increases with the development of varus deformity/instability of the knee.
  
  
  CONCLUSIONS
  Our results should prove helpful for designing new prostheses and determining clinical indications for total ankle arthroplasty.
authors: Department of Orthopaedic Surgery, Hokkaido University Graduate School of Medicine, North 15 West 7, Kita-ku, Sapporo 060-8638, Japan. tomozou@med.hokudai.ac.jp
authors: Tomohiro
authors: T
authors: Onodera
authors: Tokifumi
authors: T
authors: Majima
authors: Norimasa
authors: N
authors: Iwasaki
authors: Tamotsu
authors: T
authors: Kamishima
authors: Yasuhiko
authors: Y
authors: Kasahara
authors: Akio
authors: A
authors: Minami
mesh_terms: D015502:Absorptiometry, Photon / Q000379:methods*; D000328:Adult; D000368:Aged; D000843:Ankle Joint / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000503:physiopathology; D001178:Arthroplasty / Q000379:methods; D015519:Bone Density / Q000502:physiology; D017760:Bone Malalignment / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000503:physiopathology; D060905:Coxa Vara / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000503:physiopathology; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000000981:diagnostic imaging / Q000378:metabolism / Q000503:physiopathology; D007719:Knee Joint / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000503:physiopathology; D011474:Prosthesis Design; D013314:Stress, Mechanical; D013977:Tibia / Q000000981:diagnostic imaging / Q000378:metabolism; D014057:Tomography, X-Ray Computed / Q000379:methods*; D016474:Weight-Bearing