title: Functional implications of femoral offset following hemiarthroplasty for displaced femoral neck fracture.
abstract: Inadequate reconstruction of femoral offset after total hip arthroplasty (THA) is associated with unfavourable outcomes, but its importance following hemiarthroplasty for displaced femoral neck fracture is unknown.
  
  
  
  Our study examined the correlation between reconstructed femoral offset and functional outcome 12 months after post traumatic hemiarthroplasty in 126 prospectively enrolled elderly patients. Rotation-corrected femoral offset (FORC), relative femoral offset (FORL) and contralateral femoral offset (FOC) were measured on anteroposterior radiographs. The Harris Hip Score (HHS) was the primary outcome measure; the timed up and go (TUG) test and Lawton instrumental activities of daily living (IADL) score were secondary outcomes. Correlations were sought using the Spearman correlation coefficient (r). Sample size was calculated using an Altman nomogram, with the power set at 80 %, the significance level of 0.05 and a standardised difference of 0.75.
  
  
  
  The mean reconstructed FORC was 41 mm (17-67 mm) and showed a linear relationship and excellent correlation with the FOC. At 12 months, we found a significant positive correlation between FORC and HHS (r = 0.303, p = 0.025) and IADL (r = 0.325, p = 0.013), but not TUG (r = -0.026, p = 0.863). These findings were confirmed by bivariate and multivariate correlation between FORL and functional outcome parameters.
  
  
  
  We found a clinically relevant relationship between femoral offset and functional outcome after hemiarthroplasty in elderly patients, comparable with that of THA, for treating osteoarthritis.
authors.affiliation: Department of Trauma, Hand and Reconstructive Surgery, University of Marburg, Marburg, Germany.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Buecking
authors.affiliation: Department of Orthopaedic and Trauma Surgery, University Hospital of Cologne, Cologne, Germany.
authors.forename: Christoph Kolja
authors.initials: CK
authors.lastname: Boese
authors.affiliation: Department of Trauma, Hand and Reconstructive Surgery, University of Marburg, Marburg, Germany.
authors.forename: Verena Anna
authors.initials: VA
authors.lastname: Bergmeister
authors.affiliation: Department of Trauma, Hand and Reconstructive Surgery, University of Marburg, Marburg, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Frink
authors.affiliation: Department of Trauma, Hand and Reconstructive Surgery, University of Marburg, Marburg, Germany.
authors.forename: Steffen
authors.initials: S
authors.lastname: Ruchholtz
authors.affiliation: Department of Trauma, Hand and Reconstructive Surgery, University of Marburg, Marburg, Germany. lechler@med.uni-marburg.de.
authors.forename: Philipp
authors.initials: P
authors.lastname: Lechler
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005265:Femoral Neck Fractures / Q000150:complications / Q000601:surgery*; D005269:Femur / Q000601:surgery*; D062785:Hemiarthroplasty / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications; D011446:Prospective Studies; D016896:Treatment Outcome
keywords: Elderly patients; Femoral neck fracture; Femoral offset; Geriatric trauma; Hemiarthroplasty; Hip fracture