title: Effectiveness of Treatment for Distal Tibial Nonunions With Associated Complex Deformities Using a Hexapod External Fixator.
abstract: OBJECTIVE
  To determine the efficacy of a hexapod external fixator (TSF) and its ability to perform 6-axis correction in restoring deformities associated with distal tibial nonunions.
  
  
  METHODS
  Consecutive retrospective case review.
  
  
  METHODS
  St. Louis University Hospital. Level 1 Trauma Center.
  
  
  METHODS
  Thirty-seven patients with distal tibial nonunion with greater than 5 degrees of deformity in any plane. Patients were excluded who were less than 18 years of age, had tibial deformities less than 5 degrees, had proximal or middle tibial deformities, or had less than 1 year of follow-up.
  
  
  METHODS
  Patients with distal tibial nonunions with combined deformities were treated by the senior author with a hexapod device. Preoperative mechanical axis deviation and union status were assessed. Postoperative parameters evaluated included anatomic and mechanical axis determination and adequacy of union. Metrics include long alignment films with routine clinical follow-up.
  
  
  METHODS
  Assessment of deformity correction in 6 axes, restoration to union, and mechanical axis correction.
  
  
  RESULTS
  Average combined preoperative deformity was greater than 17.7 degrees. Average mechanical axis was restored within 5 degrees of the desired goal in all categories except in patients with severe preoperative valgus deformities. The complex nonunion group had a 94% union rate. Average time in the hexapod was 106.7 days. Average follow-up time was 2 years.
  
  
  CONCLUSIONS
  Hexapod external fixators can be used as an accurate modality to heal complex distal tibia nonunions with multifocal deformities and significant mechanical axis deviation. These difficult reconstructions are accomplished with minimum complications using these devices.
  
  
  METHODS
  Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.
authors.affiliation: Department of Orthopaedic Surgery, Saint Louis University, St. Louis, MO.
authors.forename: John E
authors.initials: JE
authors.lastname: Arvesen
authors.forename: J
authors.initials: J
authors.lastname: Tracy Watson
authors.forename: Heidi
authors.initials: H
authors.lastname: Israel
mesh_terms: D064386:Ankle Fractures / Q000000981:diagnostic imaging / Q000601:surgery*; D019544:Equipment Failure Analysis; D016267:External Fixators; D005260:Female; D005592:Fracture Fixation / Q000295:instrumentation* / Q000379:methods; D017102:Fracture Healing; D005599:Fractures, Ununited / Q000000981:diagnostic imaging / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011474:Prosthesis Design; D020127:Recovery of Function; D013977:Tibia / Q000002:abnormalities* / Q000000981:diagnostic imaging / Q000601:surgery*; D013978:Tibial Fractures / Q000000981:diagnostic imaging / Q000601:surgery*; D016896:Treatment Outcome