title: Femoral remodeling around Charnley total hip arthroplasty is unpredictable.
abstract: BACKGROUND
  There are two unusual remodeling patterns of the proximal femur around well-fixed Charnley total hip arthroplasties: cortical thinning leading to endosteal widening around the femoral component and hypertrophy of the distal femoral cortex. Previous studies have shown remodeling patterns are affected by stem design and occur early postoperatively. It is unclear if these changes are related to patient demographics or if they progress throughout the lifetime of the implant.
  
  
  OBJECTIVE
  We determined if patient demographic variables influence remodeling patterns after cemented Charnley total hip arthroplasty and if the observed remodeling changes persist long-term.
  
  
  METHODS
  We retrospectively reviewed the radiographs of 106 well-fixed Charnley femoral components. Using a novel digital edge detection program, we determined the femoral remodeling pattern and time-related changes in femoral dimensions. The minimum followup was 20 years (mean, 25.3 years; range, 19.5-37 years).
  
  
  RESULTS
  We found no association between remodeling type and age at surgery, sex, preoperative diagnosis, body mass index, or postoperative activity level. There was also no association between initial implant alignment and remodeling type. Cortical thickening in the distal hypertrophy group was an early phenomenon occurring primarily within the first 2 years, whereas cortical thinning begins later and is a more progressive process.
  
  
  CONCLUSIONS
  These data show remodeling after cemented Charnley total hip arthroplasty is not related to patient demographic variables; however, distal cortical hypertrophy can be predicted in the early postoperative period.
authors: Department of Orthopaedic Surgery, University of Iowa, UIHC, 200 Hawkins Drive, 01029 JPP, Iowa City, IA, 52242, USA.
authors: Matthew J
authors: MJ
authors: Teusink
authors: Katharine A
authors: KA
authors: Callaghan
authors: Noelle F
authors: NF
authors: Klocke
authors: Devon D
authors: DD
authors: Goetz
authors: John J
authors: JJ
authors: Callaghan
mesh_terms: D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging* / Q000601:surgery; D005500:Follow-Up Studies; D006621:Hip Joint / Q000000981:diagnostic imaging* / Q000601:surgery; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D011859:Radiography