title: Comparison of rates of union and hardware removal between large and small cannulated screws for calcaneal osteotomy.
abstract: BACKGROUND
  The calcaneal osteotomy is a common procedure to correct hindfoot malalignment. Reported union rates are high, utilizing fixation methods including staples, plates, and most commonly cannulated screws. We began our practice using 6.5 mm and 7.3 mm cannulated screws, but complaints of postoperative posterior heel pain led to hardware removal in many patients. A switch to smaller 4.5 mm cannulated screws resulted in fewer symptoms, thus we hypothesized that using a smaller screw would decrease screw removal while maintaining an equally high union rate.
  
  
  METHODS
  The records of patients who underwent a calcaneal osteotomy by 2 surgeons between January 1996 and April 2012 were retrospectively reviewed. The rates of hardware removal and union were compared between osteotomies held with two 7.3 mm, 6.5 mm, and 4.5 mm cannulated screws.
  
  
  RESULTS
  There were 272 feet that met the inclusion criteria. The hardware removal rate for 130 osteotomies held with two 7.3 mm screws was 29.2% and the removal rate for 115 osteotomies held with 4.5 mm screws was 13.0%, which was significantly different (P < .05). The removal rate for 27 osteotomies with 6.5 mm screws was 33.3%. The union rate for all groups was 100%.
  
  
  CONCLUSIONS
  Fixation of calcaneal osteotomies with two 4.5 mm screws is advantageous over larger screws with respect to future hardware removal. There was no loss of position from the smaller screws and we feel that the 4.5mm cannulated screw provides sufficient compression and achieves a high rate of union equal to that of the larger screws.
  
  
  METHODS
  Level IV, retrospective case series.
authors.affiliation: Hospital for Special Surgery, New York, NY, USA scsayres@gmail.com.
authors.forename: Stephanie C
authors.initials: SC
authors.lastname: Sayres
authors.affiliation: Georgetown School of Medicine, Washington DC, USA.
authors.forename: Yang
authors.initials: Y
authors.lastname: Gu
authors.affiliation: Hospital for Special Surgery, New York, NY, USA.
authors.forename: Samuel
authors.initials: S
authors.lastname: Kiernan
authors.affiliation: Hospital for Special Surgery, New York, NY, USA.
authors.forename: Bridget Ann
authors.initials: BA
authors.lastname: DeSandis
authors.affiliation: Hospital for Special Surgery, New York, NY, USA.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Elliott
authors.affiliation: Hospital for Special Surgery, New York, NY, USA.
authors.forename: Martin J
authors.initials: MJ
authors.lastname: O'Malley
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001863:Bone Screws; D002111:Calcaneus / Q000601:surgery*; D020878:Device Removal / Q000706:statistics & numerical data*; D004867:Equipment Design; D005260:Female; D006801:Humans; D016268:Internal Fixators; D008297:Male; D008875:Middle Aged; D010027:Osteotomy / Q000379:methods*; D012189:Retrospective Studies; D016896:Treatment Outcome; D055815:Young Adult
keywords: outcome studies; statistical analysis