title: Do Surrogates of Injury Severity Influence the Occurrence of Heterotopic Ossification in Fractures of the Acetabulum?
abstract: OBJECTIVE
  To determine the relationship between injury severity surrogates and other patient factors with the development and severity of heterotopic ossification (HO) following open reduction internal fixation of acetabular fractures treated with a posterior approach.
  
  
  METHODS
  Retrospective review.
  
  
  METHODS
  Academic level 1 trauma center.
  
  
  METHODS
  Two hundred forty-one patients who were treated through a posterior approach with a minimum of 6-month radiographic follow-up were identified from an acetabular fracture database.
  
  
  METHODS
  None.
  
  
  METHODS
  The occurrence and severity (Brooker Grade III/IV) of HO 6 months postsurgery.
  
  
  RESULTS
  Length of stay (LOS) in the intensive care unit (ICU), non-ICU LOS >10 days, and HO prophylaxis with external radiation beam therapy (XRT) were significantly associated with the development of HO in a multivariate model [ICU LOS: 1-2 days, odds ratio (OR) = 4.33, 95% confidence interval (CI): 1.03-18.25; 3-6 days, OR = 4.1, 95% CI, 1.27-13.27; >6 days, OR = 11.7, 95% CI, 3.24-42.22; non-ICU LOS >10 days (vs. 0-6 days): OR = 7.6, 95% CI, 2.6-22.25; XRT HO prophylaxis: OR = 0.29, 95% CI, 0.10-0.85]. Other variables evaluated in multivariate modeling not significantly associated with development and severity of HO included age, gender, mechanism of injury, injury severity score, presence of neurologic injury, Letournel fracture type, occurrence of hip dislocation, interval from injury to surgery, operative time, and estimated blood loss.
  
  
  CONCLUSIONS
  Surrogates of injury severity, including days in the ICU and non-ICU hospital LOS >10 days, were associated with the development of HO in our cohort of acetabular fracture patients. Prophylaxis with XRT was significantly protective against the development of HO, and the ability to provide prophylaxis is very likely related to the severity of injury.
  
  
  METHODS
  Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.
authors.affiliation: Division of Orthopaedic Trauma, Department of Orthopaedic Surgery, University of Cincinnati, Cincinnati, OH.
authors.forename: Albert
authors.initials: A
authors.lastname: dʼHeurle
authors.forename: Michael T
authors.initials: MT
authors.lastname: Archdeacon
authors.forename: Shannon
authors.initials: S
authors.lastname: Hiratzka
authors.forename: Christopher
authors.initials: C
authors.lastname: Casstevens
authors.forename: Ryan
authors.initials: R
authors.lastname: Finnan
authors.forename: Brett
authors.initials: B
authors.lastname: McCoy
mesh_terms: D000077:Acetabulum / Q000293:injuries* / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015984:Causality; D015897:Comorbidity; D005260:Female; D005593:Fracture Fixation, Internal / Q000706:statistics & numerical data; D050723:Fractures, Bone / Q000175:diagnosis / Q000453:epidemiology* / Q000601:surgery*; D006801:Humans; D015994:Incidence; D007902:Length of Stay / Q000706:statistics & numerical data; D008875:Middle Aged; D009820:Ohio / Q000453:epidemiology; D000070799:Open Fracture Reduction / Q000706:statistics & numerical data; D009999:Ossification, Heterotopic / Q000175:diagnosis* / Q000453:epidemiology*; D011379:Prognosis; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012307:Risk Factors; D012680:Sensitivity and Specificity; D015599:Trauma Severity Indices