title: Computer-assisted navigation increases precision of component placement in total knee arthroplasty.
abstract: In our clinical study, 200 total knee arthroplasties were evaluated to compare the use of the OrthoPilot system with conventional mechanical instrumentation. Long-term outcome of total knee replacement depends mainly on the accuracy of implant positioning and restoration of the mechanical leg axis. Our experience was that navigation could achieve a greater degree of accuracy concerning the aforementioned aspects. Among 513 primary-inserted total knee replacements, 100 navigated knees were compared with 100 conventionally implanted knees after matching the two groups of patients by gender, body mass index, age, preoperative deformities, radiographic findings, and operating time. Three weeks after surgery, the radiographic results were significantly better in the computer-assisted group compared with the results in the conventional group when we assessed component positioning in four axes. Only the sagittal tibial component angle was not significantly different. Total knee arthroplasty using the OrthoPilot system led to increased precision of tibial and femoral component positioning in comparison with hand-guided replacement surgery. An additional 10 minutes of operating time was acceptable. Navigation-specific complications were not seen, and the number of outliers decreased. Because computer navigation in orthopaedics is a new technology, data regarding long-term outcomes are not available.
  
  
  METHODS
  Diagnostic study, Level II-1 (retrospective study). See the Guidelines for Authors for a complete description of levels of evidence.
authors.affiliation: Department of Orthopaedic Surgery, St. Vincenz-Hospital, Danziger Strasse 17, D-33034 Brakel, Germany. rolf.haaker@gmx.de
authors.forename: Rolf G
authors.initials: RG
authors.lastname: Haaker
authors.forename: Martin
authors.initials: M
authors.lastname: Stockheim
authors.forename: Michael
authors.initials: M
authors.lastname: Kamp
authors.forename: Gunnar
authors.initials: G
authors.lastname: Proff
authors.forename: Johannes
authors.initials: J
authors.lastname: Breitenfelder
authors.forename: Andreas
authors.initials: A
authors.lastname: Ottersbach
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D011336:Probability; D011446:Prospective Studies; D011474:Prosthesis Design; D011475:Prosthesis Failure; D017755:Prosthesis Fitting; D016059:Range of Motion, Articular / Q000502:physiology; D020127:Recovery of Function; D018570:Risk Assessment; D018709:Statistics, Nonparametric; D025321:Surgery, Computer-Assisted / Q000379:methods*; D016896:Treatment Outcome