title: Osteodensitometry measurements of periprosthetic bone using dual energy X-ray absorptiometry following total knee arthroplasty.
abstract: BACKGROUND
  The present study investigates the reaction of bone density as well as the possible factors influencing this reaction following a cement-free total knee arthroplasty (TKA).
  
  
  METHODS
  Osteodensitometry scan data from 50 prospective patients with TKA was evaluated. The patients were split into two groups according to the number of follow-up investigations undertaken. No patient included in the study had received medication to increase bone density. To identify the changes in periprosthetic bone density, dual energy X-ray absorptiometry (DXA) bone density measurements in defined regions of interest (ROI) were performed over a period of 24 months postoperative. The test parameters included gender, severity of arthrosis, as well as the metric parameters T-score, body mass index, cortical bone marrow index, and the varus alignment for the respective patient.
  
  
  RESULTS
  The most significant changes in bone density were recorded within the first 3 months postoperative, in particular, the highest bone density loss was found in the region of the proximal medial tibia. Moreover, significant gender-specific associations regarding changes in bone density were established.
  
  
  CONCLUSIONS
  Finally, results achieved in the present study demonstrate that the fundamental classification in defined ROI proved to be functional and effective.
authors.affiliation: Department of Orthopaedic and Trauma Surgery, Friedrich-Schiller-University Jena at Rudolf-Elle-Hospital Eisenberg, Klosterlausnitzer Str. 81, Eisenberg, Germany. c.b.windisch@t-online.de
authors.forename: C
authors.initials: C
authors.lastname: Windisch
authors.forename: B
authors.initials: B
authors.lastname: Windisch
authors.forename: W
authors.initials: W
authors.lastname: Kolb
authors.forename: K
authors.initials: K
authors.lastname: Kolb
authors.forename: P
authors.initials: P
authors.lastname: Grützner
authors.forename: A
authors.initials: A
authors.lastname: Roth
mesh_terms: D015502:Absorptiometry, Photon; D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee; D001696:Biomechanical Phenomena; D015519:Bone Density; D005260:Female; D005269:Femur / Q000503:physiopathology*; D005360:Fibula / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000601:surgery*; D011184:Postoperative Period; D011446:Prospective Studies; D013977:Tibia / Q000503:physiopathology*