title: Intraoperative positioning of the hindfoot with the hindfoot alignment guide: a pilot study.
abstract: BACKGROUND
  In a previous study, intraoperative positioning of the hindfoot by visual means resulted in the wrong varus/valgus position by 8 degrees and a relatively large standard deviation of 8 degrees. Thus, new intraoperative means are needed to improve the precision of hindfoot surgery. We therefore sought a hindfoot alignment guide that would be as simple as the alignment guides used in total knee arthroplasty.
  
  
  METHODS
  A novel hindfoot alignment guide (HA guide) has been developed that projects the mechanical axis from the tibia down to the heel. The HA guide enables the positioning of the hindfoot in the desired varus/valgus position and in plantigrade position in the lateral plane. The HA guide was used intraoperatively from May through November 2011 in 11 complex patients with simultaneous correction of the supramalleolar, tibiotalar, and inframalleolar alignment. Pre- and postoperative Saltzman views were taken and the position was measured.
  
  
  RESULTS
  The HA guide significantly improved the intraoperative positioning compared with visual means: The accuracy with the HA guide was 4.5 ± 5.1 degrees (mean ± standard deviation) and without the HA guide 9.4 ± 5.5 degrees (P < .05). In 7 of 11 patients, the preoperative plan was changed because of the HA guide (2 avoided osteotomies, 5 additional osteotomies).
  
  
  CONCLUSIONS
  The HA guide helped to position the hindfoot intraoperatively with greater precision than visual means. The HA guide was especially useful for multilevel corrections in which the need for and the amount of a simultaneous osteotomy had to be evaluated intraoperatively.
  
  
  METHODS
  Level IV, case series.
authors.affiliation: Department of Orthopaedic Surgery, University Hospital Basel, Basel, Switzerland.
authors.forename: Arno
authors.initials: A
authors.lastname: Frigg
authors.forename: Lukas
authors.initials: L
authors.lastname: Jud
authors.forename: Victor
authors.initials: V
authors.lastname: Valderrabano
mesh_terms: D000843:Ankle Joint / Q000503:physiopathology; D058737:Arthroplasty, Replacement, Ankle / Q000295:instrumentation* / Q000592:standards; D004867:Equipment Design; D006801:Humans; D007432:Intraoperative Period; D010027:Osteotomy; D010865:Pilot Projects; D011859:Radiography; D013628:Talus / Q000000981:diagnostic imaging / Q000601:surgery; D013977:Tibia / Q000000981:diagnostic imaging / Q000601:surgery; D016474:Weight-Bearing
keywords: alignment; ankle; arthrodesis; arthroplasty; hindfoot; position