title: Computed tomography osteoabsorptiometry alterations in stress distribution patterns through the wrist after radial shortening osteotomy for Kienböck disease.
abstract: OBJECTIVE
  The distribution pattern of subchondral bone density is considered to closely reflect the stress distribution across a joint under physiological loading conditions. Our purpose was to determine alterations in the distribution pattern of subchondral bone density across the distal articular surfaces of the radius and the ulna in patients with Kienböck disease after radial shortening.
  
  
  METHODS
  We collected preoperative and postoperative computed tomography (CT) image data from 7 wrists of 7 patients who had undergone radial shortening for Kienböck disease. We measured the distribution of subchondral bone density through the distal articular surface of the radius and the ulna using a CT osteoabsorptiometry method. The obtained data were quantitatively assessed by calculating the high-density area ratio of the entire radiocarpal joint surface, scaphoid fossa, lunate fossa, and distal ulnar surface.
  
  
  RESULTS
  At the mean postoperative period of 27 months, the mean high-density area ratio in the entire distal articular surface of the radius significantly decreased from 0.413 preoperatively to 0.141 postoperatively. The postoperative value in each fossa demonstrated a significant reduction from 0.253 to 0.096 in the scaphoid fossa and from 0.160 to 0.045 in the lunate fossa. No significant alteration in the value was found in the distal ulna at follow-up.
  
  
  CONCLUSIONS
  Our CT osteoabsorptiometry analysis suggests that the distribution of subchondral bone density in both scaphoid and lunate fossae notably decreases after radial shortening. This indicates that radial shortening unloads the lunate by reducing the actual stress across the distal articular surface of the radius in subjects with Kienböck disease.
  
  
  METHODS
  Therapeutic IV.
authors.affiliation: Department of Orthopaedic Surgery and Radiology, Hokkaido University School of Medicine, Sapporo, Japan.
authors.forename: Hikaru
authors.initials: H
authors.lastname: Makabe
authors.forename: Norimasa
authors.initials: N
authors.lastname: Iwasaki
authors.forename: Tamotsu
authors.initials: T
authors.lastname: Kamishima
authors.forename: Naomi
authors.initials: N
authors.lastname: Oizumi
authors.forename: Shigeru
authors.initials: S
authors.lastname: Tadano
authors.forename: Akio
authors.initials: A
authors.lastname: Minami
mesh_terms: D015502:Absorptiometry, Photon / Q000379:methods; D000293:Adolescent; D000328:Adult; D005260:Female; D005500:Follow-Up Studies; D018737:Hand Strength / Q000502:physiology; D006801:Humans; D008297:Male; D010020:Osteonecrosis / Q000000981:diagnostic imaging* / Q000601:surgery*; D010027:Osteotomy / Q000379:methods*; D011182:Postoperative Care / Q000379:methods; D011300:Preoperative Care / Q000379:methods; D011884:Radius / Q000000981:diagnostic imaging / Q000601:surgery*; D016059:Range of Motion, Articular / Q000502:physiology*; D012494:Sampling Studies; D012720:Severity of Illness Index; D013314:Stress, Mechanical; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods; D016896:Treatment Outcome; D014955:Wrist Joint / Q000000981:diagnostic imaging / Q000601:surgery; D055815:Young Adult