title: Comparative study of subtalar arthrodesis after calcaneal frature malunion with autologous bone graft or freeze-dried xenograft.
abstract: BACKGROUND
  Calcaneal fracture malunion may evolve into arthrosis and severe foot deformities. The aim of this study was to identify differences in bony union following corrective subtalar arthrodesis with interposition of autologous tricortical bone graft or freeze-dried bovine xenograft.
  
  
  METHODS
  We prospectively evaluated 12 patients who underwent subtalar arthrodesis, six patients received autografts and 6 received freeze-dried bovine xenografts. After a mean followup of 58 weeks, the patients were clinical assessed using AOFAS scale and the visual analog scale (VAS) for pain and for final radiographic parameters measurement. Two blind raters evaluated the length of time required for solid union of the arthrodesis and graft integration by retrospective radiographic examination.
  
  
  RESULTS
  In the autograft group, AOFAS score improved from a preoperative average of 37 to 64 points postoperatively (p = 0.02) and mean VAS score improved from 4.7 to 1.9 (p = 0.028). In the xenograft group, AOFAS score improved from 38 to 74 points (p = 0.02) and VAS from 5.5 to 2.7 (p = 0.046). Solid union was achieved in all cases in the autograft group at an average of 5.3 weeks and in five cases in the xenograft group at 8.8 weeks (p = 0.077). Graft integration occurred after an average of 10.7 weeks in the autograft group and 28.8 weeks in the xenograft group (p = 0.016).
  
  
  CONCLUSIONS
  With the numbers available, no significant difference could be detected in the length of time required for solid union of subtalar arthrodesis between groups, although time to integration of freeze-dried bovine xenografts was statistically higher. Clinical and functional improvement was observed in both groups.
authors.affiliation: Department of Orthopaedics, Hospital de Clínicas de Porto Alegre, Medicine School, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2350, Zip Code 90035-003 Porto Alegre, Rio Grande do Sul, Brazil. henning.carlo@gmail.com.
authors.forename: Carlo
authors.initials: C
authors.lastname: Henning
authors.affiliation: Department of Orthopaedics, Hospital de Clínicas de Porto Alegre, Medicine School, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2350, Zip Code 90035-003 Porto Alegre, Rio Grande do Sul, Brazil. gabrielpoglia@gmail.com.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Poglia
authors.affiliation: Department of Orthopaedics, Hospital de Clínicas de Porto Alegre, Medicine School, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2350, Zip Code 90035-003 Porto Alegre, Rio Grande do Sul, Brazil. muriloleie@hotmail.com.
authors.forename: Murilo Anderson
authors.initials: MA
authors.lastname: Leie
authors.affiliation: Department of Orthopaedics, Hospital de Clínicas de Porto Alegre, Medicine School, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2350, Zip Code 90035-003 Porto Alegre, Rio Grande do Sul, Brazil. cgalia@hcpa.ufrgs.br.
authors.forename: Carlos Roberto
authors.initials: CR
authors.lastname: Galia
keywords: Arthrodesis; Bone graft; Calcaneus; Freeze-dried; Malunion; Xenograft