title: Precision of computer-assisted core decompression drilling of the knee.
abstract: BACKGROUND
  Core decompression by exact drilling into the ischemic areas is the treatment of choice in early stages of osteonecrosis of the femoral condyle. Computer-aided surgery might enhance the precision of the drilling and lower the radiation exposure time of both staff and patients. The aim of this study was to evaluate the precision of the fluoroscopically based VectorVision-navigation system in an in vitro model.
  
  
  METHODS
  Thirty sawbones were prepared with a defect filled up with a radiopaque gypsum sphere mimicking the osteonecrosis. 20 sawbones were drilled by guidance of an intraoperative navigation system VectorVision (BrainLAB, Munich, Germany). Ten sawbones were drilled by fluoroscopic control only.
  
  
  RESULTS
  A statistically significant difference with a mean distance of 0.58 mm in the navigated group and 0.98 mm in the control group regarding the distance to the desired mid-point of the lesion could be stated. Significant difference was further found in the number of drilling corrections as well as radiation time needed.
  
  
  CONCLUSIONS
  The fluoroscopic-based VectorVision-navigation system shows a high feasibility and precision of computer-guided drilling with simultaneously reduction of radiation time and therefore could be integrated into clinical routine.
authors.affiliation: Department for Orthopedic Surgery and Surgery of the Extremities, Bürgerspital Solothurn, Schöngrünstrasse 42, CH-4500 Solothurn, Switzerland. j.beckmann@asklepios.com
authors.forename: J
authors.initials: J
authors.lastname: Beckmann
authors.forename: J
authors.initials: J
authors.lastname: Goetz
authors.forename: H
authors.initials: H
authors.lastname: Bäthis
authors.forename: T
authors.initials: T
authors.lastname: Kalteis
authors.forename: J
authors.initials: J
authors.lastname: Grifka
authors.forename: L
authors.initials: L
authors.lastname: Perlick
mesh_terms: D019299:Decompression, Surgical / Q000295:instrumentation* / Q000379:methods*; D005269:Femur / Q000000981:diagnostic imaging / Q000601:surgery; D005471:Fluoroscopy; D006801:Humans; D007717:Knee / Q000000981:diagnostic imaging / Q000601:surgery*; D010020:Osteonecrosis / Q000000981:diagnostic imaging / Q000601:surgery; D011829:Radiation Dosage; D025321:Surgery, Computer-Assisted / Q000295:instrumentation / Q000379:methods*; D016896:Treatment Outcome