title: [Periprosthetic femoral bone reaction after total hip arthroplasty with preservation of the collum femoris : CT-assisted osteodensitometry 1 and 3 years postoperatively].
abstract: BACKGROUND
  Short-stemmed cementless femoral components in total hip arthroplasty have been designed to preserve the proximal femoral bone stock by load transfer to the femoral metaphysis. An in vivo method of computed tomography-assisted (CT) osteodensitometry after total hip arthroplasty is presented which differentiates between cortical and cancellous bone density (BD) changes around uncemented femoral components.
  
  
  METHODS
  Cortical and cancellous periprosthetic femoral BD (mg Ca HA/ml) was determined prospectively in 31 patients at day 10, 1 year and 3 years after total hip arthroplasty with preservation of the collum femoris (C.F.P.-stem, Link, Hamburg, Germany) using computed tomography-assisted osteodensitometry. Clinical results (Harris hip score) and plain x-rays were assessed in all cases.
  
  
  RESULTS
  Progressive proximal cortical BD loss was observed between the 1 year (Ø -8%) and 3 year (Ø -22%) postoperative measurements. Distal to the trochanter minor no significant cortical BD changes were observed. Proximal cancellous BD decreased progressively between the 1 year (Ø -33%) and 3 year (Ø -45%) analyses. The Harris hip score improved from 45 points pre-operatively to 93 points at the 3 year follow-up. All x-rays showed signs of stable ingrowth.
  
  
  CONCLUSIONS
  Periprosthetic CT osteodensitometry has the technical ability to discriminate between cortical and cancellous bone structures with respect to strain-adapted remodeling. Progressive proximal cortical and cancellous BD loss indicates that metaphyseal fixation cannot be achieved with the analyzed C.F.P. stem design. The lack of cortical BD loss below the trochanter minor suggests diaphyseal fixation of the implanted stem.
authors: Orthopädische Universitätsklinik im Waldkrankenhaus St. Marien gGmbH, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Deutschland.
authors: R
authors: R
authors: Schmidt
authors: S
authors: S
authors: Gollwitzer
authors: T E
authors: TE
authors: Nowak
authors: M
authors: M
authors: Nowak
authors: L
authors: L
authors: Häberle
authors: A
authors: A
authors: Kress
authors: R
authors: R
authors: Forst
authors: L A
authors: LA
authors: Müller
mesh_terms: D015502:Absorptiometry, Photon; D000077:Acetabulum / Q000601:surgery; D000328:Adult; D000368:Aged; D001696:Biomechanical Phenomena; D015519:Bone Density / Q000502:physiology; D005260:Female; D005500:Follow-Up Studies; D006618:Hip Dislocation, Congenital / Q000601:surgery; D006622:Hip Prosthesis; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D016348:Osseointegration / Q000502:physiology*; D015207:Osteoarthritis, Hip / Q000601:surgery; D010024:Osteoporosis / Q000150:complications*; D011446:Prospective Studies; D011474:Prosthesis Design; D011475:Prosthesis Failure; D014057:Tomography, X-Ray Computed