title: Three-dimensional analysis of image-free navigation system for total knee arthroplasty.
abstract: Malalignment causes abnormal forces that may lead to loosening after knee replacement. Whether a computer-assisted technique can improve the precision of implant positioning guaranteeing good long-term results in total knee arthroplasty, this is a matter of discussion. The authors evaluate the alignment accuracy of 20 primary total knee arthroplasties, performed using an image-free computer navigation systems, with standardized CT protocol and three-dimensional digital model reconstruction. The results of this study demonstrate that the image-free navigation system is able to improve accuracy in axial limb alignment and positioning of the components in the majority of cases; moreover, the difference between the mean mechanical axis value of the navigation system (179.7° ± 1.7°) and the median mean value obtained during the post-operative evaluation (180.3° ± 1.9°) is not statistically significant (P = 0.28).
authors.affiliation: VII Department of Orthopaedic Surgery, Rizzoli Orthopaedic Institute, University of Bologna, Via Pupilli 1, 40136 Bologna, Italy.
authors.forename: D
authors.initials: D
authors.lastname: Tigani
authors.forename: E
authors.initials: E
authors.lastname: Rimondi
authors.forename: P
authors.initials: P
authors.lastname: Trentani
authors.forename: M
authors.initials: M
authors.lastname: Ansaloni
authors.forename: L
authors.initials: L
authors.lastname: Amendola
authors.forename: D
authors.initials: D
authors.lastname: Testi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001172:Arthritis, Rheumatoid / Q000601:surgery; D019645:Arthroplasty, Replacement, Knee / Q000379:methods; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000209:etiology / Q000601:surgery*; D012189:Retrospective Studies; D025321:Surgery, Computer-Assisted / Q000379:methods; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome