title: Computer Assisted Surgery (CAS) guided arthrodesis of the foot and ankle: an analysis of accuracy in 100 cases.
abstract: BACKGROUND
  Computer Assisted Surgery (CAS) has shown the potential to increase the accuracy of surgical procedures in different fields of orthopedic surgery. The clinical experiences of 100 cases with CAS guided arthrodeses were evaluated.
  
  
  METHODS
  Two navigation systems were used (VectorVision/Navivision, Brainlab). Patients with unilateral foot and/or ankle correction arthrodesis from January 1st, 2005 to March 31st, 2008 were included. The correction was planned on the basis of clinical findings, radiographs and computer tomography. Time spent, accuracy, and problems that occurred with CAS guidance were analyzed. The accuracy was assessed by intraoperative three-dimensional imaging with ISO-C 3D or ARCADIS-3D (Siemens). The deviation from the achieved correction in comparison with the planned correction was analyzed.
  
  
  RESULTS
  One hundred patients were included (ankle, n = 19; subtalar, n = 23; ankle and subtalar, n = 12; midfoot/tarsometatarsal (TMT), n = 28, others, n = 18). The average time needed for preparation was 356 seconds (5 minutes, 56 seconds) (range, 4 to 30 minutes), the correction took an average of 28 (range, 12 to 140) seconds. The CAS system encountered malfunctions in 3 procedures (3%). In the remaining cases, all the achieved corrections were within a maximum deviation of 2 degrees/mm when compared to the planned correction (p < 0.05).
  
  
  CONCLUSIONS
  With CAS guidance for the correction of deformities of the foot and ankle, a surgeon can achieve a high degree of accuracy with a rapid correction. The high accuracy may lead to improved clinical outcomes.
authors.affiliation: Klinik für Unfallchirurgie, Orthopädie und Fusschirurgie, Klinikum Coburg, Ketschendorfer Str. 33, 96450 Coburg, Germany. info@foot-trauma.org
authors.forename: Martinus
authors.initials: M
authors.lastname: Richter
authors.forename: Stefan
authors.initials: S
authors.lastname: Zech
mesh_terms: D000842:Ankle / Q000601:surgery*; D001174:Arthrodesis / Q000379:methods* / Q000592:standards; D005528:Foot / Q000601:surgery*; D006801:Humans; D012189:Retrospective Studies; D025321:Surgery, Computer-Assisted / Q000592:standards*; D013997:Time Factors