title: Periprosthetic proximal bone loss after uncemented hip arthroplasty is related to stem size: DXA measurements in 138 patients followed for 2-7 years.
abstract: BACKGROUND
  Periprosthetic bone loss occurs around uncemented femoral stems and may be influenced by the stem size.
  
  
  METHODS
  We studied 138 consecutive patients, 3 (2-7) years on average after a total hip arthroplasty operation (THA) for unilateral osteoarthritis with the Bi-Metric uncemented femoral stem. We analyzed Harris hip score and bone mineral density.
  
  
  RESULTS
  The mean Harris hip score was 97 at follow-up. Bone mineral density decreased proximally by 19% in both Gruen zones 1 and 7. Bone loss in zones 1, 2, 6, and 7 was significantly associated with stem size. Distally, a small gain in bone mass was found in zones 3 and 5 for medium femoral sizes.
  
  
  CONCLUSIONS
  We found a marked proximal BMD loss, especially for the larger stems, which may be specific for this particular implant. Long-term studies should reveal whether this proximal bone loss will affect the longevity of the THA.
authors.affiliation: Division of Orthopaedics, Karolinska Institutet at Danderyd Hospital. Stockholm. Sweden. olof.skodenberg@ds.se
authors.forename: Olof G
authors.initials: OG
authors.lastname: Sköldenberg
authors.forename: Henrik S G
authors.initials: HS
authors.lastname: Bodén
authors.forename: Mats O F
authors.initials: MO
authors.lastname: Salemyr
authors.forename: Torbjörn E
authors.initials: TE
authors.lastname: Ahl
authors.forename: Per Y
authors.initials: PY
authors.lastname: Adolphson
mesh_terms: D015502:Absorptiometry, Photon; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D015519:Bone Density; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging / Q000473:pathology*; D005500:Follow-Up Studies; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000473:pathology / Q000601:surgery; D011474:Prosthesis Design; D013997:Time Factors