title: Postoperative radiation therapy after hip replacement in high-risk patients for development of heterotopic bone formation.
abstract: OBJECTIVE
  To report the results of postoperative radiation therapy in preventing the development of heterotopic bone formation after hip replacement surgery in high-risk patients.
  
  
  METHODS
  Between 1991 and 2007, 44 patients were preventively treated with postoperative RT after total hip replacement. In total, 47 hips were treated. All patients were considered at high risk for developing heterotopic bone formation. Most patients (63.5%) were treated because of a history of severe osteoarthritis or ankylosing spondylitis. All patients were treated with shaped parallel-opposed fields with a single fraction of 7 Gy using 6 or 18 MV photons. Most patients (94%) received radiation therapy within 72 hours postoperative and in only three patients radiation therapy was delivered after 72 hours post-surgery (5-8 days).
  
  
  RESULTS
  Minimum follow-up was 1 year. There were 18 females and 26 males. Median age was 63 years (range: 18-80). Treatments were well tolerated and no acute toxicity was seen post-radiation therapy. Only one of the 47 hips (2%) developed heterotopic bone formation. This patient received postoperative radiation therapy to both hips but only developed heterotopic bone formation in one of them. None of the three patients treated beyond 72 hours failed. To date no late toxicity has been observed.
  
  
  CONCLUSIONS
  The use of postoperative radiation therapy was an effective and safe treatment in the prevention of heterotopic bone formation in a high-risk group of patients undergoing total hip replacement.
authors.affiliation: Department of Radiation Oncology, Montreal General Hospital, McGill University Health Centre, 1650 Cedar Avenue, Montreal, Quebec H3G 1A4, Canada.
authors.forename: R
authors.initials: R
authors.lastname: Hashem
authors.forename: M
authors.initials: M
authors.lastname: Tanzer
authors.forename: N
authors.initials: N
authors.lastname: Rene
authors.forename: M
authors.initials: M
authors.lastname: Evans
authors.forename: L
authors.initials: L
authors.lastname: Souhami
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D001842:Bone and Bones; D002828:Choristoma / Q000209:etiology* / Q000517:prevention & control*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011182:Postoperative Care; D011878:Radiotherapy; D012189:Retrospective Studies; D012307:Risk Factors; D055815:Young Adult