title: The impact of class III (morbid) obesity on heterotopic ossification outcomes.
abstract: OBJECTIVE
  Obesity is associated with a chronic low inflammatory process that may act as common soil for the pathogenesis of obesity-related comorbidities including heterotopic ossification (HO). The purpose of this study is to compare the incidence of HO between patients with body mass index (BMI) <40 versus ≥40 after operative treatment of displaced acetabular fractures followed by radiation therapy (RT) ± indomethacin.
  
  
  METHODS
  This is a single institution retrospective chart review of 419 patients. All patients with well-documented BMI underwent operative treatment followed by RT ± indomethacin. All patients received 700 cGy to the soft tissues around the proximal femur and acetabulum without bone shielding. All RT were given postoperatively within 72 hours. The patients were divided into 2 groups: Group (A) BMI < 40 and Group (B) BMI ≥40. HO was assessed with X-ray. BMI was used as a surrogate measure to test the risk of HO despite prophylaxis.
  
  
  RESULTS
  The incidence of HO among all patients is 21% (89 of 419), while among those in group A (BMI <40), 68 of 374 patients developed HO (18%); in the morbidly obese group (BMI ≥40) 21of 45 patients developed HO (47%). The difference between the rates of HO in the 2 groups was 29%; the χ(2) test showed a significant difference between the 2 BMI groups (P < .001 at α = 0.05).
  
  
  CONCLUSIONS
  There is a higher incidence of HO among the morbidly obese patients despite RT ± indomethacin. RT doses for HO prophylaxis in morbidly obese patients need to be reassessed; also, understanding the signaling pathways in target tissues in obese patients at which adipokines control metabolism may reveal novel therapies. Higher radiation doses ± indomethacin may need to be considered and optimally evaluated in the context of a prospective, randomized clinical trial.
authors.affiliation: Department of Radiation Oncology, University of Mississippi Medical Center, Jackson, Mississippi; Department of Radiation Oncology, Beth Israel Medical Center, New York, New York; Department of Radiation Oncology, Albert Einstein College of Medicine of Yeshiva University, Bronx, New York. Electronic address: Waleed246@gmail.com.
authors.forename: Waleed Fouad
authors.initials: WF
authors.lastname: Mourad
authors.affiliation: Department of Radiation Oncology, University of Mississippi Medical Center, Jackson, Mississippi.
authors.forename: Satya
authors.initials: S
authors.lastname: Packianathan
authors.affiliation: Department of Epidemiology and Biostatistics, Jackson State University, Jackson, Mississippi.
authors.forename: Rania A
authors.initials: RA
authors.lastname: Shourbaji
authors.affiliation: Department of Orthopedic Surgery, University of Mississippi Medical Center, Jackson, Mississippi.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Department of Radiology, University of Mississippi Medical Center, Jackson, Mississippi.
authors.forename: Majid A
authors.initials: MA
authors.lastname: Khan
authors.affiliation: Department of Orthopedic Surgery, University of Mississippi Medical Center, Jackson, Mississippi.
authors.forename: Matthew
authors.initials: M
authors.lastname: Graves
authors.affiliation: Department of Radiation Oncology, University of Mississippi Medical Center, Jackson, Mississippi.
authors.forename: Michael C
authors.initials: MC
authors.lastname: Baird
authors.affiliation: Department of Orthopedic Surgery, University of Mississippi Medical Center, Jackson, Mississippi.
authors.forename: George
authors.initials: G
authors.lastname: Russell
authors.affiliation: Department of Radiation Oncology, University of Mississippi Medical Center, Jackson, Mississippi.
authors.forename: Srinivasan
authors.initials: S
authors.lastname: Vijayakumar