title: Subsidence of a cementless femoral component influenced by body weight and body mass index.
abstract: OBJECTIVE
  This trial was designed to evaluate the impact of physical characteristics such as body mass index, body weight and height on distal stem migration of a cementless femoral component, as the influence of obesity on the outcome of THA is still debated in literature and conflicting results have been found.
  
  
  METHODS
  In this retrospective cohort study, migration patterns for 102 implants were analysed using the Einzel-Bild-Roentgen-Analyse (EBRA-FCA, femoral component analysis). In all cases the Vision 2000 stem was implanted and combined with the Duraloc acetabular component (DePuy, Warsaw, Indiana).
  
  
  RESULTS
  The mean follow-up was 93 months. EBRA-FCA evaluations revealed a mean subsidence of 1.38 mm after two years, 2.06 mm after five and 2.24 mm after seven years. Five stems loosened aseptically. Correlation between increased migration over the whole period and aseptic loosening was highly significant (p < 0.001). Surgical technique had a significant influence on migration and stem stability (p = 0.002) but physical patient characteristics such as body weight over 75 kg and height over 165 cm also significantly influenced stem subsidence towards progressive migration (p = 0.001, p < 0.001). However, a high BMI did not trigger progressive stem migration (p = 0.87). Being of the male gender raised the odds for increased migration (p = 0.03).
  
  
  CONCLUSIONS
  Physical characteristics such as body weight and height showed significant influence on migration patterns of this cementless femoral component. The operating surgeon should be aware that body weight above 75 kg and height over 165 cm may trigger increased stem migration and the surgeon should aim to fit these prostheses as tightly as possible. However this study demonstrates that a high BMI does not trigger progressive stem migration. Further investigations are needed to confirm our findings.
authors: University Clinic of Orthopaedic Surgery, Medical University of Graz, 8036, Graz, Austria.
authors: Christoph
authors: C
authors: Stihsen
authors: Roman
authors: R
authors: Radl
authors: Armin
authors: A
authors: Keshmiri
authors: Peter
authors: P
authors: Rehak
authors: Reinhard
authors: R
authors: Windhager
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip; D001827:Body Height; D015992:Body Mass Index; D001835:Body Weight; D002484:Cementation; D005260:Female; D005500:Follow-Up Studies; D006621:Hip Joint / Q000601:surgery*; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications; D011475:Prosthesis Failure; D012189:Retrospective Studies; D016896:Treatment Outcome